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Physical Activity; Weight Control
Physical Activity Intensity and Weight Control Status Among U.S. Adults With Diabetes Paul D. Loprinzi, PhD; Gina Pariser, PT, PhD
Abstract Purpose. We have a limited understanding of the objectively determined physical activity levels by weight control status (i.e., trying to lose weight, trying to maintain weight, and neither trying to lose or m aintain weight) among U.S. adults with diabetes. Therefore, this study assessed the association between physical activity and weight control status among U.S. adults with diabetes. Design. Cross-sectional survey. Setting. The 2 0 0 3-2006 National Health and Nutrition Examination Survey (NHANES) was used, which is representative o f the U.S. population. Subjects. Subjects were 733 adults (> 20 years) with diabetes. Measures. Participants wore an accelerometer to assess physical activity, and questionnaires were used to assess weight control status and covariates. Analysis. Multivariate negative binomial regressions were used. Results. After adjustments, and compared to those not trying to lose or m aintain their weight, women trying to lose weight engaged in 74% more physical activity (rate ratio = 1.74; 95% confidence interval [Cl]: 1.14 to 2.65). Although findings were not significant fo r men, men were more likely than women to meet physical activity recommendations. Conclusion. Diabetic women trying to lose weight engaged in more physical activity than did their female counterparts not trying to lose or m aintain their weight. Although men were more active than women, no differences in activity estimates occurred across weight control status for men. (Am f Health Promot 2014;29[l]:17-22.) Key Words: Accelerometry, Diabetes, Epidemiology, NHANES, Physical Activity, Weight Control, Prevention Research. Manuscript format: quantitative research; Research purpose: modeling/relationship testing, descriptive; Study design: crosssectional; Outcome measure: behavioral; Setting: national; Health focus: physical activity, weight control; Strategy: education; Target population age: adults; Target population circumstances: education, race/ethnicity
Paul D. Loprinzi, PhD, and Gina Pariser, PT, PhD, are with the Donna and Allan Lansing School o f Nursing and Health Sciences, Bellarmine University, Louisville, Kentucky. Send re p rin t requests to Paul L oprinzi, PhD , D e p artm en t o f Exercise Science, D onna a n d Allan L ansing School o f N ursing a n d H ealth Sciences, B ellarm ine University, Louisville, KY 40205; plo p rin zi@ b ellarm in e.ed u . This m anuscript was submitted February 27 , 2013; revisions were requested A pril 2 and M ay 15, 2013; the m anuscript was accepted fo r publication July 5, 2013. Copyright © 2 0 1 4 by American Journal o f Health Promotion, Inc. 0 890-11 7 1 /1 4 /S 5 .00 -h 0 DOI: 1 0 .4 2 78/ajhp. 13 0 2 2 7-QUAN-83
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PURPOSE Adults who are overweight or obese are at an increased risk for developing diabetes.1 Although not fully under stood, the underlying mechanisms explaining this relationship may be through increased inflammation and/ or obesity-induced elevated free fatty acids, which stimulate gluconeogenesis in the liver, elevate blood levels of insulin, and ultimately increase insulin resistance and decrease insulin sensi tivity.2 Reducing adiposity, along with changes in other health behaviors, may help to reduce the prevalence and ameliorate the consequences of diabetes. Given the evidence that regular participation in physical activity may help reduce adiposity, treat diabetes, and prevent consequences associated with physical inactivity,4 increasing physical activity levels among adults with diabetes is a Healthy People 2020 objective, a public health priority. To effectively achieve this objective, it is important to understand the objec tively determined activity patterns of adults with diabetes who are trying to lose or manage their weight; particular attention should be focused on objec tive assessment of activity patterns because self-report methodology is prone to considerable measurement error, including recall and social de sirability bias.5 Currently, about half (46%) of adults in the general popu lation are trying to lose weight, 7 with about 32% of such individuals engag ing in regular leisure-time self-reported physical activity/ However, to our knowledge, no studies to date have reported objectively determined activi ty levels of adults with diabetes who are trying to lose or maintain their weight.
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Such an investigation may help inform and improve instructions by health care professionals provided to people with diabetes regarding behavior change. As an example, if adults with diabetes who are trying to lose or maintain their weight are indeed insufficiendy active, this may help prompt the development and imple mentation of behavior change strate gies, such as objective monitoring of padent physical activity behavior to help further facilitate activity among those trying to lose weight. Therefore, the primary objective of this study was to describe accelerome ter-assessed physical activity levels by weight control status (i.e., trying to lose weight, trying to maintain weight, and neither trying to lose or maintain weight) among a nationally represen tative sample of adults with evidence of diabetes. A secondary objective of this study was to compare objectively mea sured physical activity levels across weight control status between those with and without diabetes.
diabetes, (2) if they are now taking insulin, and (3) if they are now taking diabetic pills to lower blood sugar. In the present study, participants who answered yes to any of these three questions were considered to have evidence of diabetes. A subsample (one-half randomly selected) of the NHANES participants was examined in a morning fasting session. Fasting glucose was measured from a blood sample, and participants with a fasting glucose level of 126 mg/dL or higher was considered to have evidence of diabetes.9 Last, participants with an A1C level of 6.5% or greater were considered to have diabetes.10 Assessment of Weight Control Status.
Sample After excluding participations who had insufficient accelerometry data, were pregnant, had missing data on the covariates, and had missing weight control status data, 733 adults (396 males; 337 females) >20 years of age demonstrated evidence of diabetes, with 4572 not having diabetes.
Participants were asked questions re lated to their weight control status. For the present study, three mutually ex clusive categories were created, which included trying to lose weight, trying to maintain weight, and neither trying to lose or maintain weight. First, participants were asked to self-report their current weight and weight from 1 year ago. Then, for participants who self-report ed a weight loss of 10 or more pounds, they were asked to indicate if their weight loss was intentional. All partic ipants, with the exception of those whose weight loss was intentional, were then asked if they are currently trying to lose weight. Participants were then asked, “During the past 12 months, have you done anything to keep from gaining weight” Participants who self-reported an intentional weight loss of at least 10 pounds or who were currently trying to lose weight were classified as trying to lose weight. Those who indicated that they had been doing something to keep from gaining weight but were not classified as trying to lose weight were classified as trying to maintain their weight. Last, those who reported not tiying to lose or maintain their weight were classified as neither trying to lose or maintain weight.
Measures
Assessment of Physical Activity. Partici
METHODS Design Data from the present study were obtained from the 2003-2006 National Health and Nutrition Examination Survey (NHANES), which is a crosssectional survey. NHANES uses a rep resentative sample of noninstitutionalized U.S. civilians selected by a complex, multistage probability de sign. Further details about NHANES can be found elsewhere.8
Assessment of Diabetes Status. Partici-
pants were asked several questions related to diabetes. Participants were asked (1) if they ever had been told by a doctor or health professional that they had or have diabetes or sugar
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pants who were not prevented by impairments of walking or wearing an accelerometer were issued an ActiGraph 7164 accelerometer. Partici pants were asked to wear the accelerometer on the right hip for 7 days following their examination. The
accelerometer was affixed to an elastic belt worn around the waist. The output of an accelerometer is in activity counts, which are proportional to an individual’s acceleration. Detailed in formation on the ActiGraph acceler ometer can be found elsewhere.11 For the present study, accelerometry data was collected in 1-minute epoch inter vals, with data presented as 1-minute bouts. Participants were classified as meeting physical activity guidelines if they engaged in 150 minutes of mod erate-intensity or 75-minutes of vigor ous-intensity physical activity per week, or some combination of the two.12 To account for a combination of moder ate and vigorous intensity physical activity (MVPA), minutes of vigorous intensity per week were multiplied by 2 before being added to time spent at moderate intensity per week.18 Activity counts/min > 2020 and < 5999 were considered moderate intensity, and activity counts/min > 5999 were con sidered to be vigorous-intensity activi ty.14 For the analyses described here, and to represent habitual activity pat terns, only those participants with at least 4 days with 10 or more hours per day of monitoring data were included in the analyses.14 Nonwear was defined by a period of a minimum of 60 consecutive minutes of zero activity counts, with the allowance of 1 to 2 minutes of activity counts between 0 and 100.14 Assessment of Covariates. Information
about age, gender, race-ethnicity, and poverty-to-income ratio (PIR) were obtained from a questionnaire. As a measure of socioeconomic status, a PIR value below 1 is considered to be below the poverty threshold. Additionally, a comorbidity index variable1'’ 11’ was created to classify number of comor bidities each participant had. Partici pants were classified as having 0, 1,2, or 3+ comorbidities based on selfreport of the following chronic diseas es and/or events: arthritis, coronaiy heart disease, stroke, congestive heart failure, cancer, heart attack, emphyse ma, and chronic bronchitis. Hyperten sion was also included as a comorbidity, although the presence of hypertension was not based on self-report but rather a measured systolic blood pressure > 140 mm Hg, a measured diastolic
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Table 1 Demographic Characteristics of the Analyzed Sample by Gender and Diabetes Status (Weighted Mean/Proportion [Standard Error]), NHANES 2003-2006* Without Diabetes
With Diabetes Variable
Men (n = 396)
Women (n = 337)
Men (n = 2364)
Women (n = 2208)
Age (y) Race-ethnicity % Non-Hispanic White Poverty-to-income (PIR) score Body mass index (BMI; kg/m2) % Normal weight (BMI < 25) % Overweight (BMI = 25-29.9) % Obese (BMI > 30) Comorbidity index % 0 Comorbidities % 1 Comorbidity % 2 Comorbidities % 3+ Comorbidities Weight control behaviors % Trying to lose weight % Trying to maintain weight % Not trying to lose or maintain weight Physical activity Moderate-to-vigorous intensity (min/d) % Meeting physical activity guidelines
57.9 (1.0)
61.1 (0.9)
46.0 (0.5)
48.1 (0.5)
67.8 3.0 30.9 15.0 31.9 52.9
(3.8) (0.1) (0.4) (2.8) (3.4) (3.2)
63.4 2.5 32.1 15.4 30.4 54.1
(4.0) (0.1) (0.5) (2.6) (2.6) (3.5)
75.9 3.2 27.9 29.0 42.3 28.6
(2.0) (0.1) (0.1) (1.4) (1.2) (1.5)
75.3 3.1 27.7 40.2 29.3 30.3
(2.2) (0.1) (0.2) (1.7) (1.3) (1.3)
23.8 33.8 21.9 20.3
(2.7) (2.9) (2.3) (2.7)
15.5 23.1 34.8 26.4
(2.5) (3.2) (3.8) (4.3)
56.5 25.6 10.5 7.3
(1.5) (1.0) (0.7) (0.7)
48.7 28.1 15.6 7.5
(1.3) (1.2) (0.8) (0.5)
49.5 (3.0) 10.4 (2.1) 40.0 (3.0)
59.5 (4.1) 9.7 (1.7) 30.6 (3.9)
35.6 (1.2) 12.3 (1.0) 52.0 (1.4)
55.1 (1.2) 10.4 (0.9) 34.4 (1.0)
15.8 (1.3) 25.7 (3.9)
8.6 (0.6) 10.7 (1.9)
31.9 (0.7) 59.3 (1.3)
18.3 (0.5) 34.0 (1.6)
* NHANES indicates National Health and Nutrition Examination Survey.
blood pressure > 90 mm Hg, or rep o rted use of blood pressure-lowering m edication. Body mass index (BMI) was calculated from m easured weight and height (weight in kilograms divided by the square of height in m eters). Norm al weight was defined as a BMI < 25; overweight 25 to 29.9; and obese > 30.17 Analysis All statistical analyses were per form ed using procedures from sample survey data using STATA (version 12.0, College Station, Texas) to account for the com plex survey design used in NHANES. To account for oversam pling, nonresponse, and noncoverage, and to provide nationally representa tive estimates, all analyses included the use of appropriate survey sample weights, clustering, and prim ary sam pling units. New sample weights were created for the com bined NHANES cycles following analytical guidelines for the continuous NHANES.18 W hen an analysis resulted in a stratum with a single cluster, the variance contribu tion from such a stratum was centered at the overall cluster mean.
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Because women tend to report trying to lose weight m ore frequently than do m en, results for the present study are reported separately for m en and women. Means and standard errors were calculated for continuous variables, and proportions were calculated for categorical variables. T he m edian MVPA estimates o f the weight control status groups were fit as a continuous variable to estimate the tren d across weight control status groups in a linear regression model. Beyond probability testing, the magni tude of associations was estim ated using T|2 . Adjusted Wald tests were used to test for differences in activity levels across diabetes status. Multivariate assessment of the asso ciation between MVPA and weight control status was exam ined using a negative binom ial regression because MVPA (outcom e variable expressed in integral m inutes) failed tests of nor mality. Rate ratios from the negative binom ial regression reflect the rate of events for each variable in the model while holding the o ther variables in the m odel constant. For the negative bi-
nomial regression m odel, not trying to lose or maintain weight served as the referent group. Models were adjusted for age, BMI, race-ethnicity, PIR, and comorbidity index with models computed separately for gender and diabetes status. Statistical significance was established as p < .05. RESULTS Results of the participant character istics of the study variables are shown in Table 1 for both women and men across diabetes status. Weighted physi cal activity estimates across weight control status and diabetes status are shown in Table 2. W omen with diabetes who were trying to lose weight engaged in m ore MVPA than their female counterparts trying to m aintain their weight or n o t trying to lose o r m aintain their weight. Results were similar for women w ithout diabetes in that those n o t trying to lose or m aintain their weight engaged in less MVPA than did their counterparts. Results were n o t significant for m en with or without diabetes. A lthough findings were not
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Table 2 Weighted Physical Activity Estimates Across Weight Control and Diabetes Status Among Men and Women, NHANES 2003-2006f
Physical Activity Intensity
Weight Control Behaviors; Mean (95% Cl)
Weight Control Behaviors; Mean (95% Cl)
Trying to Lose Weight
Trying to Lose Weight
Trying to Maintain Weight
Not Trying to Lose or Maintain Weight
p**
i|2
With Diabetes
Trying to Maintain Weight
Not Trying to Lose or Maintain Weight
p*
n2
Without Diabetes
Men MVPA (min/d) Women MVPA (min/d)
16.0 (12.5-19.5) 12.6 (7.7-17.5) 10.3(8.4-12.1)
16.4(12.5-20.2) 0.61
7.5(2.9-12.1)
5.7 (3.5-7.9)
0.01 30.6(28.4-32.9) 31.9 (26.9-36.9) 32.7 (31.1-34.3) 0.99 0.01
0.003 0.26 19.1(17.8-20.3) 19.3(16.6-22.1)
16.9 (14.8-19.0) 0.04 0.13
t NHANES indicates National Health and Nutrition Examination Survey; and MVPA, moderate-to-vigorous physical activity. * The median MVPA physical activity estimates of the weight control status groups were fit as continuous variables to estimate the trend across weight control status groups in a linear regression model.
significant for men, men engaged in more physical activity than did women. Regardless of gender, few participants with diabetes who were trying to lose weight were sufficiently active (i.e., met physical activity guidelines); only 12.5% and 36.7%, respectively, of women and men met current physical activity guidelines. Table 3 shows the multivariate asso ciation between weight control status and physical activity across gender and diabetes status. After adjusting for age, race-ethnicity, PIR, BMI, and comor bidity index, and compared to those not trying to lose or maintain their
weight, women with diabetes trying to lose weight engaged in 74% (rate ratio = 1.74; 95% Cl: 1.14 to 2.65) more MVPA. Although not the main focus on the study, significant covariates included age, BMI, PIR and comorbidity index. In general, and while holding all variables constant, those who were older, those who had a higher BMI, and those with more comorbidities tended to engage in less physical activity, whereas those who had a higher PIR score (indicating greater socioeconomic status) tended to en gage in more physical activity.
The secondary objective of this study was to compare objectively measured physical activity levels across weight control status between those with and without diabetes. For both men and women, those with diabetes engaged in less physical activity than did those without diabetes for each weight con trol behavior (p < .05; Table 2). DISCUSSION The primary aim of this study was to describe accelerometer-assessed activity patterns of a population-based sample
Table 3 Negative Binomial Regression Results for Moderate-to-Vigorous Physical Activity (Outcome Variable) and Weight Control Behavior (Independent Variable) for Adult Men and Women With and Without Diabetes, NHANES 2003-2006f Rate Ratio (95% Cl)* Men Variable Not trying to lose or maintain weight Trying to lose weight Training to maintain weight Covariates Age, 1 year older Non-White vs. White PIR, 1 unit higher BMI, 1 kg/m2 higher 1 Comorbidity vs. 0 comorbidities 2 Comorbidity vs. 0 comorbidities 3 + Comorbidity vs. 0 comorbidities
Rate Ratio (95% Cl)* Women
Rate Ratio (95% Cl)* Men
With Diabetes
Rate Ratio (95% Cl)* Women
Without Diabetes
Referent 1.09 (0.79-1.51) 0.77 (0.52-1.14)
Referent 1.74 (1.14-2.65) 1.80 (0.76-4.24)
Referent 1.04 (0.95-1.13) 1.00 (0.86-1.17)
Referent 1.10 (0.96-1.26) 1.14 (0.96-1.36)
0.97 1.36 1.05 0.96 1.01 0.67 0.67
0.96 0.83 0.95 0.95 1.66 0.98 0.84
0.97 1.13 1.07 0.97 0.95 0.74 0.55
0.98 1.08 1.08 0.97 1.02 0.81 0.48
(0.96-0.98) (1.04-1.79) (0.96-1.15) (0.94-0.98) (0.66-1.54) (0.41-1.10) (0.36-1.26)
(0.94-0.97) (0.65-1.06) (0.88-1.02) (0.93-0.97) (1.17-2.36) (0.65-1.47) (0.53-1.33)
(0.97-0.98) (1.04-1.23) (1.04—1.10) (0.96-0.98) (0.86-1.05) (0.66-0.84) (0.43-0.70)
(0.97-0.98) (0.95-1.24) (1.05-1.11) (0.96-0.98) (0.92—1.13) (0.67-0.97) (0.37-0.64)
t NHANES indicates National Health and Nutrition Examination Survey; Cl, confidence interval; PIR, poverty-to-income ratio; and BMI, body mass index. * Bold indicates statistical significance (p < 0.05).
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of adults with diabetes by weight control status. The main findings of this study were fourfold: (1) physical activity estimates did not differ across weight control status for men with diabetes; (2) women with diabetes trying to lose weight or maintain their weight engaged in more physical ac tivity than their female counterparts not trying to lose or maintain their weight; (B) for both men and women, those with diabetes engaged in less physical activity than did those without diabetes for each weight control be havior; and (4) both men and women with diabetes trying to lose weight, in particular, engaged in insufficient lev els of physical activity. The gender-discrepant findings in the present study are difficult to explain. It is possible that men who were trying to lose weight or maintain their weight were employing other weight loss strategies, such as reducing caloric intake,19 which might help to explain the null findings for this gender. We recognize that there are numerous psychosocial factors influ encing behavioral intention and phys ical activity behavior, which can be explained by several theoretical frame works, such as the social cognitive model, the transtheoretical model, and the theory of planned behavior, to name a few. It is also possible that women, compared to men, had greater use of key cognitive and behavioral physical activity-related strategies. This, of course, cannot be confirmed in the present study. However, there is some recent evidence to support this specu lation. Men and women aged 50 to 65 years who were at an increased risk for diabetes participated in the Good Ageing in Lahti Region Lifestyle Im plementation Trial.-0 After the inter vention, women had increased their exercise plans more than men, sug gesting that increased action planning, which may be considered theoretically similar to behavior intention, may in part explain the gender-discrepant findings. Additionally, the findings in the present study may also be ex plained by the fact that women, com pared to men, are more likely to try and change risk behaviors-1 and are more concerned with weight loss.2-’ Along these lines, Davis and Cowles23 showed that women, compared to
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men, were more dissatisfied with their bodies and were more likely to exercise to try and lose weight. An important finding of the present study was that both men and women with diabetes who were trying to lose or maintain their weight did not engage in the recommended levels of physical activity. This has major implications for informing and improving the practice of health care professionals. Specifi cally, this finding suggests that clini cians should not exclusively rely on their patients’ behavioral intention to lose weight. Indeed, and in support of the present study, recent evidence demonstrates that behavioral intention is not a strong predictor of actual selfreported physical activity behavior among adults with diabetes.24 There fore, clinicians should not assume that their patients’ intentions to lose weight is indicative of their actual physical activity behavior. As a result, health care professionals are encouraged to increase patients’ knowledge of their actual physical activity behavior and awareness of the minimum level of physical activity needed to improve health and sustain weight loss. To promote weight loss, the American College of Sports Medi cine25 recommends 150 to 250 minutes per week of moderate-intensity physi cal activity, with greater amounts (>250 minutes) providing greater weight loss. To sustain weight loss in adulthood, the Dietary Guidelines for Americans20 suggest 60 to 90 minutes of daily moderate-intensity physical activity. Health care professionals are well suited to provide physical activityrelated guidance and direction.27 Spe cific awareness and attention to the minimum recommended dose of physical activity (i.e., 150 min/wk of at least moderate-intensity activity) should be emphasized, with the provi sion of directions and support on achieving this level of physical activity in a progressive manner. To help their patients achieve the desired dose of physical activity, clinicians should identify their patients’ physical activityrelated barriers and provide strategies to overcome these barriers. Common barriers reported among adults with diabetes include various medical-relat ed conditions, such as peripheral neuropathy and degenerative joint
disease.28 Adults with diabetes who have more barriers tend to place less importance on physical activity for controlling their diabetes.28 Conse quently, it is crucial that clinicians help these individuals overcome their barri ers and become more active by, for example, teaching them proper exer cises that strengthen muscles and increase mobility of arthritic joints as well as identifying exercises that are tolerable for those with certain medial conditions, such as peripheral neu ropathy. Lastly, to increase their pa tients’ awareness of their actual physical activity behavior, clinicians should consider using objective mea sures of physical activity to assess their actual physical activity behavior and teach them how to use such devices (e.g., pedometers) to promote physical activity monitoring. Limitations to the present study include the cross-sectional study de sign, which does not allow changes in physical activity across weight control status to be observed. Additionally, weight control status was subjectively determined, and questions asked par ticipants to report whether they were, for example, trying to lose weight over the last 12 months; therefore, it is possible that the time frame in which the physical activity was assessed did not necessarily match the time frame in which they engaged in the respective weight control behavior. However, de spite these limitations, major strengths of this study include employing an objective measure of physical activity, describing activity estimates across weight control status in a nationally representative sample of adults with diabetes, and making comparisons to those without diabetes. We encourage future research, particularly among those with diabetes, to examine whether physical activity estimates across weight control status are modi fied by race-ethnicity, adiposity, and socioeconomic status. Examining pos sible effect modifications was not pos sible in die present study because the percentage of participants with diabe tes in these groups across the weight control status categories were too low to render meaningful estimates. In summary, women with diabetes trying to lose weight engaged in more physical activity than did their female
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counterparts not trying to lose or maintain their weight; although men were more active than women, no differences in activity estimates oc curred across weight control status for men. Also, adults with diabetes en gaged in less physical activity than did their counterparts across each weight control behavior. Additionally, on av erage, both men and women with diabetes who were trying to lose or maintain their weight did not engage in the recommended levels of physical activity.
SO WHAT? Implications for Health Promotion Practitioners and Researchers What is already known on this topic?
Regular engagement in physical activity is effective in reducing adi posity and preventing and treating diabetes. However, we have a limited understanding of the activity patterns of adults with diabetes who are trying to lose or maintain their weight. What does this article add?
This study demonstrates that adults with diabetes who are trying to lose weight are not engaging in sufficient levels of physical activity. Additional ly, men with diabetes who are trying to lose weight are not engaging in more physical activity than their counterparts who are not trying to lose or maintain their weight. What are the implications for health promotion practice or research?
Health care professionals are en couraged to increase their patients’ (particularly those with diabetes) awareness of the minimum level of physical activity needed to lose weight and treat diabetes as well as help them achieve this dose of physical activity.
R e fe re n c e s
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3. Fabricatore AN, Wadden TA. Treatment of obesity: an overview. Clini Diabetes. 2003;21: 67-72. 4. Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: Joint Position Statement. Diabetes Care. 2010;33: el47-el67. 5. Shephard RJ. Limits to the measurement o f habitual physical activity by questionnaires. Br J Sports Med. 2003;37: 197-206; discussion, 206. 6. Bish CL, Blanck HM, Serdula MK, et al. Diet and physical activity behaviors among Americans trying to lose weight: 2000 Behavioral Risk Factor Surveillance System. Obes Res. 2005;13:596-607. 7. Kruger J, Yore MM, Kohl HW III. Leisure time physical activity patterns by weight control status: 1999-2002 NHANES. Med Sci Sports Exerc. 2007;39:788-795. 8. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey. Available at: h ttp :// www.cdc.gov/ nch s/n h an es/ about_nhanes.htm. Accessed )uly 14, 2013. 9. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2010;33(suppl 1):S62-S69. 10. American Diabetes Association. Executive summary: standards of medical care in diabetes—2012. Diabetes Care 2012; 35 (suppl 1):S4-S10. 11. Chen KY, Bassett DR Jr. The technology of accelerometry-based activity monitors: current and future. Med Sci Sports Exerc. 2005;37:S490-S500. 12. US Departm ent of Health and Human Services. Physical activity guidelines for Americans. Available at: http://www. healtli.gov/paguidelines/. Accessed July 12, 2013. 13. Tucker JM, Welk GJ, Beyler NK. Physical activity in US: adults compliance with the Physical Activity Guidelines for Americans. Am JPrev Med. 2011;40:454-461. 14. Troiano RP, Berrigan D, Dodd KW, et al. Physical activity in the United States measured by accelerometer. Med Sci Sports Exerc. 2008;40:181-188. 15. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40:373-383. 16. Quan H, Li B, Courts CM, et al. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 2011;173: 676-682.
17. World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation. WHO Technical Report Series 894. Geneva, Switzerland: World Health Organization; 2000. 18. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey. Specifying weight parameters. Available at: h ttp :// www.cdc.gov/nchs/tutorials/NHANES/ SurveyDesign/Weighting/Task2.htm. Accessed July 15, 2013. 19. McGuire MT, Wing RR, Klem ML, et al. Long-term maintenance of weight loss: do people who lose weight through various weight loss methods use different behaviors to maintain their weight? Int J Obes Relat Metab Disord. 1998;22:572-577. 20. Hankonen N, Absetz P, Ghisletta P, et al. Gender differences in social cognitive determinants o f exercise adoption. Psychol Health. 2010;25:55-69. 21. Assaf AR, Parker D, Lapane KL, et al. Does the Y chromosome make a difference? Gender differences in attempts to change cardiovascular disease risk factors. J Womens Health (Larchmt). 2003;12:321-330. 22. Lee C. Women’s Health: Psychological and Social Perspectives. Thousand Oakes, Calif: Sage; 1998. 23. Davis C, Cowles M. Body image and exercise: a study of relationships and comparisons between physically active men and women. Sex Rales. 1991;25:33-44. 24. Hardeman W, Kinmonth AL, Michie S, Sutton S. Theory of planned behaviour cognitions do not predict self-reported or objective physical activity levels or change in the ProActive trial. Br J Health Psychol 2011;16:135-150. 25. Donnelly JE, Blair SN, Jakicic JM, et al. American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc. 2009;41:459471. 26. US Department of Health and Human Services, US Department of Agriculture. Dietary guidelines for Americans. Available at: http://www.fda.gov/ohrms/ dockets/dockets/06q0458/ 06q-0458-sup000T02.pdf. Accessed July 15, 2013. 27. American Association of Diabetes Educators. AADE positon statement: diabetes and physical activity. Diabetes Educ. 2012;38:129-132. 28. Dutton GR, Johnson J, Whitehead D, et al. Barriers to physical activity among predominantly low-income AfricanAmerican patients with type 2 diabetes. Diabetes Care. 2005;28:1209-1210.
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Physical Activity; Weight Control
Physical Activity Intensity and Weight Control Status Among U.S. Adults With Diabetes Paul D. Loprinzi, PhD; Gina Pariser, PT, PhD
Abstract Purpose. We have a limited understanding of the objectively determined physical activity levels by weight control status (i.e., trying to lose weight, trying to maintain weight, and neither trying to lose or m aintain weight) among U.S. adults with diabetes. Therefore, this study assessed the association between physical activity and weight control status among U.S. adults with diabetes. Design. Cross-sectional survey. Setting. The 2 0 0 3-2006 National Health and Nutrition Examination Survey (NHANES) was used, which is representative o f the U.S. population. Subjects. Subjects were 733 adults (> 20 years) with diabetes. Measures. Participants wore an accelerometer to assess physical activity, and questionnaires were used to assess weight control status and covariates. Analysis. Multivariate negative binomial regressions were used. Results. After adjustments, and compared to those not trying to lose or m aintain their weight, women trying to lose weight engaged in 74% more physical activity (rate ratio = 1.74; 95% confidence interval [Cl]: 1.14 to 2.65). Although findings were not significant fo r men, men were more likely than women to meet physical activity recommendations. Conclusion. Diabetic women trying to lose weight engaged in more physical activity than did their female counterparts not trying to lose or m aintain their weight. Although men were more active than women, no differences in activity estimates occurred across weight control status for men. (Am f Health Promot 2014;29[l]:17-22.) Key Words: Accelerometry, Diabetes, Epidemiology, NHANES, Physical Activity, Weight Control, Prevention Research. Manuscript format: quantitative research; Research purpose: modeling/relationship testing, descriptive; Study design: crosssectional; Outcome measure: behavioral; Setting: national; Health focus: physical activity, weight control; Strategy: education; Target population age: adults; Target population circumstances: education, race/ethnicity
Paul D. Loprinzi, PhD, and Gina Pariser, PT, PhD, are with the Donna and Allan Lansing School o f Nursing and Health Sciences, Bellarmine University, Louisville, Kentucky. Send re p rin t requests to Paul L oprinzi, PhD , D e p artm en t o f Exercise Science, D onna a n d Allan L ansing School o f N ursing a n d H ealth Sciences, B ellarm ine University, Louisville, KY 40205; plo p rin zi@ b ellarm in e.ed u . This m anuscript was submitted February 27 , 2013; revisions were requested A pril 2 and M ay 15, 2013; the m anuscript was accepted fo r publication July 5, 2013. Copyright © 2 0 1 4 by American Journal o f Health Promotion, Inc. 0 890-11 7 1 /1 4 /S 5 .00 -h 0 DOI: 1 0 .4 2 78/ajhp. 13 0 2 2 7-QUAN-83
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PURPOSE Adults who are overweight or obese are at an increased risk for developing diabetes.1 Although not fully under stood, the underlying mechanisms explaining this relationship may be through increased inflammation and/ or obesity-induced elevated free fatty acids, which stimulate gluconeogenesis in the liver, elevate blood levels of insulin, and ultimately increase insulin resistance and decrease insulin sensi tivity.2 Reducing adiposity, along with changes in other health behaviors, may help to reduce the prevalence and ameliorate the consequences of diabetes. Given the evidence that regular participation in physical activity may help reduce adiposity, treat diabetes, and prevent consequences associated with physical inactivity,4 increasing physical activity levels among adults with diabetes is a Healthy People 2020 objective, a public health priority. To effectively achieve this objective, it is important to understand the objec tively determined activity patterns of adults with diabetes who are trying to lose or manage their weight; particular attention should be focused on objec tive assessment of activity patterns because self-report methodology is prone to considerable measurement error, including recall and social de sirability bias.5 Currently, about half (46%) of adults in the general popu lation are trying to lose weight, 7 with about 32% of such individuals engag ing in regular leisure-time self-reported physical activity/ However, to our knowledge, no studies to date have reported objectively determined activi ty levels of adults with diabetes who are trying to lose or maintain their weight.
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Such an investigation may help inform and improve instructions by health care professionals provided to people with diabetes regarding behavior change. As an example, if adults with diabetes who are trying to lose or maintain their weight are indeed insufficiendy active, this may help prompt the development and imple mentation of behavior change strate gies, such as objective monitoring of padent physical activity behavior to help further facilitate activity among those trying to lose weight. Therefore, the primary objective of this study was to describe accelerome ter-assessed physical activity levels by weight control status (i.e., trying to lose weight, trying to maintain weight, and neither trying to lose or maintain weight) among a nationally represen tative sample of adults with evidence of diabetes. A secondary objective of this study was to compare objectively mea sured physical activity levels across weight control status between those with and without diabetes.
diabetes, (2) if they are now taking insulin, and (3) if they are now taking diabetic pills to lower blood sugar. In the present study, participants who answered yes to any of these three questions were considered to have evidence of diabetes. A subsample (one-half randomly selected) of the NHANES participants was examined in a morning fasting session. Fasting glucose was measured from a blood sample, and participants with a fasting glucose level of 126 mg/dL or higher was considered to have evidence of diabetes.9 Last, participants with an A1C level of 6.5% or greater were considered to have diabetes.10 Assessment of Weight Control Status.
Sample After excluding participations who had insufficient accelerometry data, were pregnant, had missing data on the covariates, and had missing weight control status data, 733 adults (396 males; 337 females) >20 years of age demonstrated evidence of diabetes, with 4572 not having diabetes.
Participants were asked questions re lated to their weight control status. For the present study, three mutually ex clusive categories were created, which included trying to lose weight, trying to maintain weight, and neither trying to lose or maintain weight. First, participants were asked to self-report their current weight and weight from 1 year ago. Then, for participants who self-report ed a weight loss of 10 or more pounds, they were asked to indicate if their weight loss was intentional. All partic ipants, with the exception of those whose weight loss was intentional, were then asked if they are currently trying to lose weight. Participants were then asked, “During the past 12 months, have you done anything to keep from gaining weight” Participants who self-reported an intentional weight loss of at least 10 pounds or who were currently trying to lose weight were classified as trying to lose weight. Those who indicated that they had been doing something to keep from gaining weight but were not classified as trying to lose weight were classified as trying to maintain their weight. Last, those who reported not tiying to lose or maintain their weight were classified as neither trying to lose or maintain weight.
Measures
Assessment of Physical Activity. Partici
METHODS Design Data from the present study were obtained from the 2003-2006 National Health and Nutrition Examination Survey (NHANES), which is a crosssectional survey. NHANES uses a rep resentative sample of noninstitutionalized U.S. civilians selected by a complex, multistage probability de sign. Further details about NHANES can be found elsewhere.8
Assessment of Diabetes Status. Partici-
pants were asked several questions related to diabetes. Participants were asked (1) if they ever had been told by a doctor or health professional that they had or have diabetes or sugar
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pants who were not prevented by impairments of walking or wearing an accelerometer were issued an ActiGraph 7164 accelerometer. Partici pants were asked to wear the accelerometer on the right hip for 7 days following their examination. The
accelerometer was affixed to an elastic belt worn around the waist. The output of an accelerometer is in activity counts, which are proportional to an individual’s acceleration. Detailed in formation on the ActiGraph acceler ometer can be found elsewhere.11 For the present study, accelerometry data was collected in 1-minute epoch inter vals, with data presented as 1-minute bouts. Participants were classified as meeting physical activity guidelines if they engaged in 150 minutes of mod erate-intensity or 75-minutes of vigor ous-intensity physical activity per week, or some combination of the two.12 To account for a combination of moder ate and vigorous intensity physical activity (MVPA), minutes of vigorous intensity per week were multiplied by 2 before being added to time spent at moderate intensity per week.18 Activity counts/min > 2020 and < 5999 were considered moderate intensity, and activity counts/min > 5999 were con sidered to be vigorous-intensity activi ty.14 For the analyses described here, and to represent habitual activity pat terns, only those participants with at least 4 days with 10 or more hours per day of monitoring data were included in the analyses.14 Nonwear was defined by a period of a minimum of 60 consecutive minutes of zero activity counts, with the allowance of 1 to 2 minutes of activity counts between 0 and 100.14 Assessment of Covariates. Information
about age, gender, race-ethnicity, and poverty-to-income ratio (PIR) were obtained from a questionnaire. As a measure of socioeconomic status, a PIR value below 1 is considered to be below the poverty threshold. Additionally, a comorbidity index variable1'’ 11’ was created to classify number of comor bidities each participant had. Partici pants were classified as having 0, 1,2, or 3+ comorbidities based on selfreport of the following chronic diseas es and/or events: arthritis, coronaiy heart disease, stroke, congestive heart failure, cancer, heart attack, emphyse ma, and chronic bronchitis. Hyperten sion was also included as a comorbidity, although the presence of hypertension was not based on self-report but rather a measured systolic blood pressure > 140 mm Hg, a measured diastolic
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Table 1 Demographic Characteristics of the Analyzed Sample by Gender and Diabetes Status (Weighted Mean/Proportion [Standard Error]), NHANES 2003-2006* Without Diabetes
With Diabetes Variable
Men (n = 396)
Women (n = 337)
Men (n = 2364)
Women (n = 2208)
Age (y) Race-ethnicity % Non-Hispanic White Poverty-to-income (PIR) score Body mass index (BMI; kg/m2) % Normal weight (BMI < 25) % Overweight (BMI = 25-29.9) % Obese (BMI > 30) Comorbidity index % 0 Comorbidities % 1 Comorbidity % 2 Comorbidities % 3+ Comorbidities Weight control behaviors % Trying to lose weight % Trying to maintain weight % Not trying to lose or maintain weight Physical activity Moderate-to-vigorous intensity (min/d) % Meeting physical activity guidelines
57.9 (1.0)
61.1 (0.9)
46.0 (0.5)
48.1 (0.5)
67.8 3.0 30.9 15.0 31.9 52.9
(3.8) (0.1) (0.4) (2.8) (3.4) (3.2)
63.4 2.5 32.1 15.4 30.4 54.1
(4.0) (0.1) (0.5) (2.6) (2.6) (3.5)
75.9 3.2 27.9 29.0 42.3 28.6
(2.0) (0.1) (0.1) (1.4) (1.2) (1.5)
75.3 3.1 27.7 40.2 29.3 30.3
(2.2) (0.1) (0.2) (1.7) (1.3) (1.3)
23.8 33.8 21.9 20.3
(2.7) (2.9) (2.3) (2.7)
15.5 23.1 34.8 26.4
(2.5) (3.2) (3.8) (4.3)
56.5 25.6 10.5 7.3
(1.5) (1.0) (0.7) (0.7)
48.7 28.1 15.6 7.5
(1.3) (1.2) (0.8) (0.5)
49.5 (3.0) 10.4 (2.1) 40.0 (3.0)
59.5 (4.1) 9.7 (1.7) 30.6 (3.9)
35.6 (1.2) 12.3 (1.0) 52.0 (1.4)
55.1 (1.2) 10.4 (0.9) 34.4 (1.0)
15.8 (1.3) 25.7 (3.9)
8.6 (0.6) 10.7 (1.9)
31.9 (0.7) 59.3 (1.3)
18.3 (0.5) 34.0 (1.6)
* NHANES indicates National Health and Nutrition Examination Survey.
blood pressure > 90 mm Hg, or rep o rted use of blood pressure-lowering m edication. Body mass index (BMI) was calculated from m easured weight and height (weight in kilograms divided by the square of height in m eters). Norm al weight was defined as a BMI < 25; overweight 25 to 29.9; and obese > 30.17 Analysis All statistical analyses were per form ed using procedures from sample survey data using STATA (version 12.0, College Station, Texas) to account for the com plex survey design used in NHANES. To account for oversam pling, nonresponse, and noncoverage, and to provide nationally representa tive estimates, all analyses included the use of appropriate survey sample weights, clustering, and prim ary sam pling units. New sample weights were created for the com bined NHANES cycles following analytical guidelines for the continuous NHANES.18 W hen an analysis resulted in a stratum with a single cluster, the variance contribu tion from such a stratum was centered at the overall cluster mean.
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Because women tend to report trying to lose weight m ore frequently than do m en, results for the present study are reported separately for m en and women. Means and standard errors were calculated for continuous variables, and proportions were calculated for categorical variables. T he m edian MVPA estimates o f the weight control status groups were fit as a continuous variable to estimate the tren d across weight control status groups in a linear regression model. Beyond probability testing, the magni tude of associations was estim ated using T|2 . Adjusted Wald tests were used to test for differences in activity levels across diabetes status. Multivariate assessment of the asso ciation between MVPA and weight control status was exam ined using a negative binom ial regression because MVPA (outcom e variable expressed in integral m inutes) failed tests of nor mality. Rate ratios from the negative binom ial regression reflect the rate of events for each variable in the model while holding the o ther variables in the m odel constant. For the negative bi-
nomial regression m odel, not trying to lose or maintain weight served as the referent group. Models were adjusted for age, BMI, race-ethnicity, PIR, and comorbidity index with models computed separately for gender and diabetes status. Statistical significance was established as p < .05. RESULTS Results of the participant character istics of the study variables are shown in Table 1 for both women and men across diabetes status. Weighted physi cal activity estimates across weight control status and diabetes status are shown in Table 2. W omen with diabetes who were trying to lose weight engaged in m ore MVPA than their female counterparts trying to m aintain their weight or n o t trying to lose o r m aintain their weight. Results were similar for women w ithout diabetes in that those n o t trying to lose or m aintain their weight engaged in less MVPA than did their counterparts. Results were n o t significant for m en with or without diabetes. A lthough findings were not
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Table 2 Weighted Physical Activity Estimates Across Weight Control and Diabetes Status Among Men and Women, NHANES 2003-2006f
Physical Activity Intensity
Weight Control Behaviors; Mean (95% Cl)
Weight Control Behaviors; Mean (95% Cl)
Trying to Lose Weight
Trying to Lose Weight
Trying to Maintain Weight
Not Trying to Lose or Maintain Weight
p**
i|2
With Diabetes
Trying to Maintain Weight
Not Trying to Lose or Maintain Weight
p*
n2
Without Diabetes
Men MVPA (min/d) Women MVPA (min/d)
16.0 (12.5-19.5) 12.6 (7.7-17.5) 10.3(8.4-12.1)
16.4(12.5-20.2) 0.61
7.5(2.9-12.1)
5.7 (3.5-7.9)
0.01 30.6(28.4-32.9) 31.9 (26.9-36.9) 32.7 (31.1-34.3) 0.99 0.01
0.003 0.26 19.1(17.8-20.3) 19.3(16.6-22.1)
16.9 (14.8-19.0) 0.04 0.13
t NHANES indicates National Health and Nutrition Examination Survey; and MVPA, moderate-to-vigorous physical activity. * The median MVPA physical activity estimates of the weight control status groups were fit as continuous variables to estimate the trend across weight control status groups in a linear regression model.
significant for men, men engaged in more physical activity than did women. Regardless of gender, few participants with diabetes who were trying to lose weight were sufficiently active (i.e., met physical activity guidelines); only 12.5% and 36.7%, respectively, of women and men met current physical activity guidelines. Table 3 shows the multivariate asso ciation between weight control status and physical activity across gender and diabetes status. After adjusting for age, race-ethnicity, PIR, BMI, and comor bidity index, and compared to those not trying to lose or maintain their
weight, women with diabetes trying to lose weight engaged in 74% (rate ratio = 1.74; 95% Cl: 1.14 to 2.65) more MVPA. Although not the main focus on the study, significant covariates included age, BMI, PIR and comorbidity index. In general, and while holding all variables constant, those who were older, those who had a higher BMI, and those with more comorbidities tended to engage in less physical activity, whereas those who had a higher PIR score (indicating greater socioeconomic status) tended to en gage in more physical activity.
The secondary objective of this study was to compare objectively measured physical activity levels across weight control status between those with and without diabetes. For both men and women, those with diabetes engaged in less physical activity than did those without diabetes for each weight con trol behavior (p < .05; Table 2). DISCUSSION The primary aim of this study was to describe accelerometer-assessed activity patterns of a population-based sample
Table 3 Negative Binomial Regression Results for Moderate-to-Vigorous Physical Activity (Outcome Variable) and Weight Control Behavior (Independent Variable) for Adult Men and Women With and Without Diabetes, NHANES 2003-2006f Rate Ratio (95% Cl)* Men Variable Not trying to lose or maintain weight Trying to lose weight Training to maintain weight Covariates Age, 1 year older Non-White vs. White PIR, 1 unit higher BMI, 1 kg/m2 higher 1 Comorbidity vs. 0 comorbidities 2 Comorbidity vs. 0 comorbidities 3 + Comorbidity vs. 0 comorbidities
Rate Ratio (95% Cl)* Women
Rate Ratio (95% Cl)* Men
With Diabetes
Rate Ratio (95% Cl)* Women
Without Diabetes
Referent 1.09 (0.79-1.51) 0.77 (0.52-1.14)
Referent 1.74 (1.14-2.65) 1.80 (0.76-4.24)
Referent 1.04 (0.95-1.13) 1.00 (0.86-1.17)
Referent 1.10 (0.96-1.26) 1.14 (0.96-1.36)
0.97 1.36 1.05 0.96 1.01 0.67 0.67
0.96 0.83 0.95 0.95 1.66 0.98 0.84
0.97 1.13 1.07 0.97 0.95 0.74 0.55
0.98 1.08 1.08 0.97 1.02 0.81 0.48
(0.96-0.98) (1.04-1.79) (0.96-1.15) (0.94-0.98) (0.66-1.54) (0.41-1.10) (0.36-1.26)
(0.94-0.97) (0.65-1.06) (0.88-1.02) (0.93-0.97) (1.17-2.36) (0.65-1.47) (0.53-1.33)
(0.97-0.98) (1.04-1.23) (1.04—1.10) (0.96-0.98) (0.86-1.05) (0.66-0.84) (0.43-0.70)
(0.97-0.98) (0.95-1.24) (1.05-1.11) (0.96-0.98) (0.92—1.13) (0.67-0.97) (0.37-0.64)
t NHANES indicates National Health and Nutrition Examination Survey; Cl, confidence interval; PIR, poverty-to-income ratio; and BMI, body mass index. * Bold indicates statistical significance (p < 0.05).
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of adults with diabetes by weight control status. The main findings of this study were fourfold: (1) physical activity estimates did not differ across weight control status for men with diabetes; (2) women with diabetes trying to lose weight or maintain their weight engaged in more physical ac tivity than their female counterparts not trying to lose or maintain their weight; (B) for both men and women, those with diabetes engaged in less physical activity than did those without diabetes for each weight control be havior; and (4) both men and women with diabetes trying to lose weight, in particular, engaged in insufficient lev els of physical activity. The gender-discrepant findings in the present study are difficult to explain. It is possible that men who were trying to lose weight or maintain their weight were employing other weight loss strategies, such as reducing caloric intake,19 which might help to explain the null findings for this gender. We recognize that there are numerous psychosocial factors influ encing behavioral intention and phys ical activity behavior, which can be explained by several theoretical frame works, such as the social cognitive model, the transtheoretical model, and the theory of planned behavior, to name a few. It is also possible that women, compared to men, had greater use of key cognitive and behavioral physical activity-related strategies. This, of course, cannot be confirmed in the present study. However, there is some recent evidence to support this specu lation. Men and women aged 50 to 65 years who were at an increased risk for diabetes participated in the Good Ageing in Lahti Region Lifestyle Im plementation Trial.-0 After the inter vention, women had increased their exercise plans more than men, sug gesting that increased action planning, which may be considered theoretically similar to behavior intention, may in part explain the gender-discrepant findings. Additionally, the findings in the present study may also be ex plained by the fact that women, com pared to men, are more likely to try and change risk behaviors-1 and are more concerned with weight loss.2-’ Along these lines, Davis and Cowles23 showed that women, compared to
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men, were more dissatisfied with their bodies and were more likely to exercise to try and lose weight. An important finding of the present study was that both men and women with diabetes who were trying to lose or maintain their weight did not engage in the recommended levels of physical activity. This has major implications for informing and improving the practice of health care professionals. Specifi cally, this finding suggests that clini cians should not exclusively rely on their patients’ behavioral intention to lose weight. Indeed, and in support of the present study, recent evidence demonstrates that behavioral intention is not a strong predictor of actual selfreported physical activity behavior among adults with diabetes.24 There fore, clinicians should not assume that their patients’ intentions to lose weight is indicative of their actual physical activity behavior. As a result, health care professionals are encouraged to increase patients’ knowledge of their actual physical activity behavior and awareness of the minimum level of physical activity needed to improve health and sustain weight loss. To promote weight loss, the American College of Sports Medi cine25 recommends 150 to 250 minutes per week of moderate-intensity physi cal activity, with greater amounts (>250 minutes) providing greater weight loss. To sustain weight loss in adulthood, the Dietary Guidelines for Americans20 suggest 60 to 90 minutes of daily moderate-intensity physical activity. Health care professionals are well suited to provide physical activityrelated guidance and direction.27 Spe cific awareness and attention to the minimum recommended dose of physical activity (i.e., 150 min/wk of at least moderate-intensity activity) should be emphasized, with the provi sion of directions and support on achieving this level of physical activity in a progressive manner. To help their patients achieve the desired dose of physical activity, clinicians should identify their patients’ physical activityrelated barriers and provide strategies to overcome these barriers. Common barriers reported among adults with diabetes include various medical-relat ed conditions, such as peripheral neuropathy and degenerative joint
disease.28 Adults with diabetes who have more barriers tend to place less importance on physical activity for controlling their diabetes.28 Conse quently, it is crucial that clinicians help these individuals overcome their barri ers and become more active by, for example, teaching them proper exer cises that strengthen muscles and increase mobility of arthritic joints as well as identifying exercises that are tolerable for those with certain medial conditions, such as peripheral neu ropathy. Lastly, to increase their pa tients’ awareness of their actual physical activity behavior, clinicians should consider using objective mea sures of physical activity to assess their actual physical activity behavior and teach them how to use such devices (e.g., pedometers) to promote physical activity monitoring. Limitations to the present study include the cross-sectional study de sign, which does not allow changes in physical activity across weight control status to be observed. Additionally, weight control status was subjectively determined, and questions asked par ticipants to report whether they were, for example, trying to lose weight over the last 12 months; therefore, it is possible that the time frame in which the physical activity was assessed did not necessarily match the time frame in which they engaged in the respective weight control behavior. However, de spite these limitations, major strengths of this study include employing an objective measure of physical activity, describing activity estimates across weight control status in a nationally representative sample of adults with diabetes, and making comparisons to those without diabetes. We encourage future research, particularly among those with diabetes, to examine whether physical activity estimates across weight control status are modi fied by race-ethnicity, adiposity, and socioeconomic status. Examining pos sible effect modifications was not pos sible in die present study because the percentage of participants with diabe tes in these groups across the weight control status categories were too low to render meaningful estimates. In summary, women with diabetes trying to lose weight engaged in more physical activity than did their female
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counterparts not trying to lose or maintain their weight; although men were more active than women, no differences in activity estimates oc curred across weight control status for men. Also, adults with diabetes en gaged in less physical activity than did their counterparts across each weight control behavior. Additionally, on av erage, both men and women with diabetes who were trying to lose or maintain their weight did not engage in the recommended levels of physical activity.
SO WHAT? Implications for Health Promotion Practitioners and Researchers What is already known on this topic?
Regular engagement in physical activity is effective in reducing adi posity and preventing and treating diabetes. However, we have a limited understanding of the activity patterns of adults with diabetes who are trying to lose or maintain their weight. What does this article add?
This study demonstrates that adults with diabetes who are trying to lose weight are not engaging in sufficient levels of physical activity. Additional ly, men with diabetes who are trying to lose weight are not engaging in more physical activity than their counterparts who are not trying to lose or maintain their weight. What are the implications for health promotion practice or research?
Health care professionals are en couraged to increase their patients’ (particularly those with diabetes) awareness of the minimum level of physical activity needed to lose weight and treat diabetes as well as help them achieve this dose of physical activity.
R e fe re n c e s
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3. Fabricatore AN, Wadden TA. Treatment of obesity: an overview. Clini Diabetes. 2003;21: 67-72. 4. Colberg SR, Sigal RJ, Fernhall B, et al. Exercise and type 2 diabetes: the American College of Sports Medicine and the American Diabetes Association: Joint Position Statement. Diabetes Care. 2010;33: el47-el67. 5. Shephard RJ. Limits to the measurement o f habitual physical activity by questionnaires. Br J Sports Med. 2003;37: 197-206; discussion, 206. 6. Bish CL, Blanck HM, Serdula MK, et al. Diet and physical activity behaviors among Americans trying to lose weight: 2000 Behavioral Risk Factor Surveillance System. Obes Res. 2005;13:596-607. 7. Kruger J, Yore MM, Kohl HW III. Leisure time physical activity patterns by weight control status: 1999-2002 NHANES. Med Sci Sports Exerc. 2007;39:788-795. 8. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey. Available at: h ttp :// www.cdc.gov/ nch s/n h an es/ about_nhanes.htm. Accessed )uly 14, 2013. 9. American Diabetes Association. Diagnosis and classification of diabetes mellitus. Diabetes Care. 2010;33(suppl 1):S62-S69. 10. American Diabetes Association. Executive summary: standards of medical care in diabetes—2012. Diabetes Care 2012; 35 (suppl 1):S4-S10. 11. Chen KY, Bassett DR Jr. The technology of accelerometry-based activity monitors: current and future. Med Sci Sports Exerc. 2005;37:S490-S500. 12. US Departm ent of Health and Human Services. Physical activity guidelines for Americans. Available at: http://www. healtli.gov/paguidelines/. Accessed July 12, 2013. 13. Tucker JM, Welk GJ, Beyler NK. Physical activity in US: adults compliance with the Physical Activity Guidelines for Americans. Am JPrev Med. 2011;40:454-461. 14. Troiano RP, Berrigan D, Dodd KW, et al. Physical activity in the United States measured by accelerometer. Med Sci Sports Exerc. 2008;40:181-188. 15. Charlson ME, Pompei P, Ales KL, MacKenzie CR. A new method of classifying prognostic comorbidity in longitudinal studies: development and validation. J Chronic Dis 1987;40:373-383. 16. Quan H, Li B, Courts CM, et al. Updating and validating the Charlson comorbidity index and score for risk adjustment in hospital discharge abstracts using data from 6 countries. Am J Epidemiol 2011;173: 676-682.
17. World Health Organization. Obesity: Preventing and Managing the Global Epidemic. Report of a WHO Consultation. WHO Technical Report Series 894. Geneva, Switzerland: World Health Organization; 2000. 18. Centers for Disease Control and Prevention. National Health and Nutrition Examination Survey. Specifying weight parameters. Available at: h ttp :// www.cdc.gov/nchs/tutorials/NHANES/ SurveyDesign/Weighting/Task2.htm. Accessed July 15, 2013. 19. McGuire MT, Wing RR, Klem ML, et al. Long-term maintenance of weight loss: do people who lose weight through various weight loss methods use different behaviors to maintain their weight? Int J Obes Relat Metab Disord. 1998;22:572-577. 20. Hankonen N, Absetz P, Ghisletta P, et al. Gender differences in social cognitive determinants o f exercise adoption. Psychol Health. 2010;25:55-69. 21. Assaf AR, Parker D, Lapane KL, et al. Does the Y chromosome make a difference? Gender differences in attempts to change cardiovascular disease risk factors. J Womens Health (Larchmt). 2003;12:321-330. 22. Lee C. Women’s Health: Psychological and Social Perspectives. Thousand Oakes, Calif: Sage; 1998. 23. Davis C, Cowles M. Body image and exercise: a study of relationships and comparisons between physically active men and women. Sex Rales. 1991;25:33-44. 24. Hardeman W, Kinmonth AL, Michie S, Sutton S. Theory of planned behaviour cognitions do not predict self-reported or objective physical activity levels or change in the ProActive trial. Br J Health Psychol 2011;16:135-150. 25. Donnelly JE, Blair SN, Jakicic JM, et al. American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc. 2009;41:459471. 26. US Department of Health and Human Services, US Department of Agriculture. Dietary guidelines for Americans. Available at: http://www.fda.gov/ohrms/ dockets/dockets/06q0458/ 06q-0458-sup000T02.pdf. Accessed July 15, 2013. 27. American Association of Diabetes Educators. AADE positon statement: diabetes and physical activity. Diabetes Educ. 2012;38:129-132. 28. Dutton GR, Johnson J, Whitehead D, et al. Barriers to physical activity among predominantly low-income AfricanAmerican patients with type 2 diabetes. Diabetes Care. 2005;28:1209-1210.
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