This article was downloaded by: [Michigan State University] On: 28 February 2015, At: 12:10 Publisher: Routledge Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37-41 Mortimer Street, London W1T 3JH, UK
Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Statin use and self-reported swimming performance in US masters swimmers a
a
a
Kyle Terpak , Sally Guthrie & Steven Erickson a
College of Pharmacy, University of Michigan, Ann Arbor, United States Published online: 05 Aug 2014.
Click for updates To cite this article: Kyle Terpak, Sally Guthrie & Steven Erickson (2015) Statin use and self-reported swimming performance in US masters swimmers, Journal of Sports Sciences, 33:3, 286-292, DOI: 10.1080/02640414.2014.942688 To link to this article: http://dx.doi.org/10.1080/02640414.2014.942688
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Sports Sciences, 2015 Vol. 33, No. 3, 286–292, http://dx.doi.org/10.1080/02640414.2014.942688
Statin use and self-reported swimming performance in US masters swimmers
KYLE TERPAK, SALLY GUTHRIE & STEVEN ERICKSON College of Pharmacy, University of Michigan, Ann Arbor, United States
Downloaded by [Michigan State University] at 12:10 28 February 2015
(Accepted 27 June 2014)
Abstract Exercise and treating hyperlipidaemia with statins are two integral components of the American Heart Association guidelines to reduce cardiovascular risk in adults. Since statins can cause myalgias and myopathies, they could affect the duration or intensity of an exercise regimen. To determine the impact of statin use in adult masters swimmers, a survey was distributed to examine the association between swimming performance and statin usage in adult swimmers (≥35 years). After excluding those with chronic diseases or taking drugs that reduce physical capacity, 749 swimmers (118 taking statins, 73 not taking statins to control elevated cholesterol and 558 controls) were included in a regression model to determine the factors significantly affecting the duration and intensity of swimming workouts. Age and gender were significantly (P ≤ 0.001) associated with the distance swam per 60 min. Younger, male swimmers completed more yards per 60-min workout. Use of statins was not significantly associated with yards swam per 60-min workout. Nor did statin usage affect the number of swim sessions per month or the length of swim session. Evidently, statins do not cause enough fatigue or pain in masters swimmers to require a decrease in the duration or intensity of workouts. Keywords: swimming, statin therapy, swim performance, coenzyme Q10
1. Introduction Heart disease is a major health problem worldwide and is especially prevalent in more affluent countries, such as the United States. To combat this disease, the American Heart Association (AHA) recently released guidelines for the treatment of cholesterol to reduce atherosclerotic cardiovascular risk in adults (Stone et al., 2013). In conjunction with recommendations for treatment of cholesterol, the AHA also released a guideline on lifestyle management to reduce cardiovascular risk that includes the recommendation for three to four 40-min sessions weekly of moderate- to vigorous-intensity physical activity (Eckel et al., 2013). One method of meeting the recommendations for physical activity that is gaining support in America is swimming. Swimming is the fourth most popular sports activity in the United States (US Census Bureau, 2012), while the United States Masters Swimming (USMS) organisation has a current membership of nearly 60,000 swimmers of all ability (United States Masters Swimming, 2013). Although prior studies indicate USMS members regard themselves as generally healthier than age-
matched people in the general US population, even this active group of individuals remain at risk for cardiovascular disease as they age (Guthrie, Erickson, & Lau, 2013). In addition to lifestyle management, one major strategy suggested by the AHA to reduce atherosclerotic cardiovascular risk is the use of the statin class of cholesterol-lowering drugs (Stone et al., 2013). Since 1998, the proportion of those aged 45 and older that use statins has increased dramatically (National Center for Health Statistics, 2011). While statins effectively lower cholesterol and are generally well tolerated, they are not without adverse effects. Reports of skeletal muscle pain (myalgias) and inflammation (myositis) or, rarely, necrosis (rhabdomyolysis) in individuals treated with statins are especially important for those who maintain an active lifestyle (Buettner, Davis, Leveille, Mittleman, & Mukamal, 2008; Krishnan & Thompson, 2010; Staffa, Chang, & Green, 2002; Tomlinson & Mangione, 2005). Additional evidence indicates that statin-induced myalgias are more frequent in older individuals and more physically active individuals (Mancini et al., 2011; Meador & Huey, 2010).
Correspondence: Steven R. Erickson, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor 48109-1065, United States. E-mail: [email protected] © 2014 Taylor & Francis
Statins and performance in masters swimmers To determine the impact of statin use in adult masters swimmers, this study examined the association between the duration, distance and intensity of swimming workouts and statin usage in adult swimmers. This was done using data obtained from those who completed a survey sent to registered USMS members. We hypothesised that there would be an association between statin use and a decrease in distance, duration and intensity of swimming in USMS members even after adjustment for age and the presence of a chronic disease.
287
Table I. Survey questions regarding swimming workouts and medications. 1. Over the past 30 days, how many separate swimming workouts have you done? _______ times 2. If you swam at least once over the past 30 days, what was the average length of time of your workouts? _______ min 3. If you swam at least once over the past 30 days, what was the average distance swam per workout? _________ yards/metres 4. Below are listed common illnesses. Please read this list and check off an illness if a physician has ever diagnosed or told you that you have it: High blood pressure High blood cholesterol Diabetes
2. Methods
Downloaded by [Michigan State University] at 12:10 28 February 2015
2.1. Data collection The data used in this study were obtained from an Internet-based survey distributed to the USMS population in late 2010. The 54,949 swimmers registered with USMS in 2010 who were 21 years of age or older were invited to take part. The Sports Medicine Committee of USMS and the university’s Investigational Review Board gave approval for the study, and informed consent was obtained from all who participated in the survey. Swimmers were notified by a study announcement sent to all registered USMS members in October and November 2010 via an Internet newsletter. The newsletter contained a web link that directed the responder to a detailed overview of the project, including an informed consent. Those agreeing to take part were then directed via web link to the first page of the survey. No incentives were provided for participation in the survey. Individual-identifying data were not collected; all results were anonymous. The data collected included demographic data as well as self-reported characteristics of adult masters swimmers including the number of swim workouts per month, the length of time of each swim workout and average yards swam per workout session. Health-related variables including the presence of chronic diseases were also queried (Table I). Additionally, respondents were asked to document the use of prescription and non-prescription drugs and dietary supplements. Medication or supplement dose and frequency were not reported, nor was the duration of time that respondents had been taking these medications and supplements. Those who were taking the dietary supplement coenzyme Q10 (CoQ10) were identified because of this agent’s potential use as a treatment for statin-induced myalgias (Venero & Thompson, 2009). 2.2. Inclusion and exclusion criteria Although the database contained responses from swimmers aged ≥21 years, only those with ≥35 years of age were included in our analyses. The age threshold of 35 was
Heart failure Irregular heart beat or arrhythmia Coronary artery disease (ischemic heart disease) Cancer Arthritis Lung disease (asthma or other chronic lung disease) Depression Anxiety Migraine/recurrent headaches Allergies (eyes and nose) Stomach or intestinal ulcer (peptic ulcer disease) Osteoporosis Anaemia Stroke Thyroid problem Liver problem Chronic bronchitis 5. There are many other illnesses than those listed above that people can have. Please list below in your own words any other chronic condition that you may have that was diagnosed by a physician. (free text space was provided for as much information as the respondent chose to enter) 6. Please list ALL medications that you are currently taking, including those prescribed by your physician(s), any over-the-counter medications (such as aspirin) and any herbal products, dietary supplements such as creatine, or vitamin/mineral supplements: (free text space was provided for as many medications and supplements as the respondent chose to enter) 7. Of the medicines and supplements listed above, are there any that you think may be impairing your ability to exercise to the fullest extent? Yes
No
If yes, please record which one(s) and a brief description of the effect it is having
chosen due to the increased likelihood of receiving statin therapy, since routine assessment of cardiovascular risk factors, including serum lipid levels, begins at this age. Our analyses also excluded those reporting chronic diseases likely associated with reduced physical capacity, including multiple sclerosis, rheumatoid arthritis, osteoarthritis, lupus, fibromyalgia, spinal pain, chronic pain, gout, HIV, non-skin cancer, cystic fibrosis, Parkinson’s, Lyme disease,
288
K. Terpak et al.
Epstein–Barr and other neuropathies. In addition, those taking beta-blockers were excluded from further analyses, since this class of medications has been associated with decreased physical performance (Asplund, 2010). An adjusted value for distance swam per 60-min workout was used to judge swimming intensity. This was calculated by taking the average yards swam per workout, dividing this value by the average number of min per workout and then multiplying by 60.
deviation) or frequencies (percentage) for all demographic and swimming variables and compared using Student’s t-test for continuous variables and two-sided Fisher’s exact test for categorical variables. Since four ttests were conducted, the Bonferroni test was used to adjust alpha to ≤0.0125 for these comparisons. Multivariate linear regression models for each swimming performance outcome were conducted to determine the association between taking CoQ10 and swimming performance outcome measures, controlling for subject variables.
Downloaded by [Michigan State University] at 12:10 28 February 2015
2.3. Statistical methods 2.3.1. Sample size. Based on the data from the USMS, the average swim workout of USMS swimmers is approximately 2500 yards (Guthrie et al., 2013). Distance swam in workouts reflects overall endurance and is associated with a number of performance indicators for swimming. Therefore, yards swam per workout was selected as the primary measure of swimming performance to determine the sample size calculation. Assuming that a 500-yard difference in yards swam is a significant difference in performance (20% difference), using a standard deviation of 1000 yards, an alpha of 0.05 and power of 0.8, the sample size for each group was 50. 2.3.2. Statistical tests. The study sample was characterised using mean (standard deviation) or frequencies (percentage) for all demographic and swimming variables. Demographics and swimming performance variables were compared among three groups: (group 1) those currently taking statins, (group 2) those who have a history of elevated cholesterol but are not taking statins and (group 3) those not taking statins. Group 3 had no history of elevated cholesterol and is considered the control group. Analyses of variance (ANOVAs) were used for continuous variables and two-sided Chi-square or Fisher’s exact test for categorical variables. A P-value of 0.05 or less was used as a threshold for statistically significant differences. Since the comparison of demographic and swimming performance variables among the three groups required four different ANOVA tests, the alpha value was adjusted using Bonferroni test to ≤0.0125. Multivariate linear regression was used to determine the association between swimming performance outcomes (number of swim sessions per month, length of time of each swim session, average yards swam per workout session and average yards swam per 60 min) and the independent variables of demographics (age, gender, race and education) and statin usage (groups 1, 2 or 3). A secondary analysis of the potential effect of CoQ10 on swimming workout outcomes in those who concomitantly take a statin was conducted on those within the statin group (group 1). The CoQ10 and non-CoQ10 groups were characterised using mean (standard
3. Results The original sample contained 1054 completed surveys. After including only those aged 35 and older and excluding those with chronic diseases that may impair performance or who used beta-blockers, a total of 749 swimmers were included from the online survey data. Of those, 118 patients reported statin use (group 1), an additional 73 reported that they had been diagnosed with high blood cholesterol but they were not taking statins (group 2) and 558 were not taking statins and did not have high blood cholesterol (group 3). Population characteristics of the three groups are listed in Table II. Both age and gender were significantly different among the three groups, with statin users being older and more likely male. Regarding swimming performance outcomes, the post hoc Scheffe’s test identified that the control group (group 3) swam significantly more yards per workout and significantly more yards per 60 min than the statin users (group 1). Multivariate linear regressions were performed to determine the association between the specific swimming outcomes of interest and statin use groups, age, gender, race and education. Results of each model are shown in Table III. The multivariate linear regression indicated that statin use did not exhibit a significant impact on any swimming performance variables. However, age was significantly associated with the length of each workout, the average yards swam per workout and the average yards swam per 60-min workout (P = 0.02, P < 0.001 and P < 0.001, respectively). The average number of yards swam per workout session and the average yards swam per 60-min workout were significantly associated with both gender and age, with younger age and male gender being significantly associated with swimming longer distances per workout. Using this regression model, the statin use groups did not significantly predict any of the swimming performance variables after adjustment for age and gender. We also wanted to determine if the use of CoQ10 supplementation was associated with differences in
Statins and performance in masters swimmers
Table IV. Description of swimmers who took statins alone versus those taking statins and CoQ10.
Table II. Population characteristics. Group 1
Group 2
Group 3
Statin users, Non-statin Controls, mean (s) or users, mean mean (s) or frequency (s) or frequency (%) frequency (%) (%)
Downloaded by [Michigan State University] at 12:10 28 February 2015
Variable Age Gender Male Female Race Caucasian Minority Education Up to high school College/ beyond Yards swam per 60-min workout Number of swim sessions in the past 30 days Average min per workout Average yards per workout
N = 558
N = 73
62.7 (9.6)
54.3 (9.2)*
69 (59%) 48 (41%)
28 (39%) 44 (61%)
199 (36%) 358 (64%)
≤0.001
114 (97%) 3 (3%)
72 (99%) 1 (1%)
542 (98%) 13 (2%)
=0.85
1 (1%)
0 (0%)
4 (1%)
117 (99%)
73 (100%)
552 (99%)
2366.0 (592.8)
2461.4 (648.8)
13.7 (6.8)
13.7 (6.1)
P-value
52.3 (9.8)* ≤0.0001
=0.75
2614.6 =0.0114 (922.3)* 14.3 (6.4)
66.2 (18.1)
65.5 (17.5)
2470 (969) 2702 (1017)
2860 (1357)*
CoQ10 user, mean (s) or frequency (%)
Non-CoQ10 user, mean (s) or frequency (%)
N = 16
N = 102
P-value
63.9 (7.2)
63.3 (9.7)
0.79
11 (68.8) 5 (31.2)
57 (55.9) 44 (43.1)
0.42
15 (93.8) 1 (6.3)
100 (98.0) 2 (2.0)
0.36
0
6 (5.9)
1.00
16 (100)
96 (94.1)
2620.5 (595.9)
2445.5 (700.1)
0.35
13.7 (5.5)
13.9 (7.1)
0.89
69.4 (23.4)
62.3 (19.6)
0.19
3069 (1483)
2508.7 (963)
0.05
Variable
N = 118
62.8 (18.9)
289
=0.49
Age Gender Male Female Race White Non-white Education Up to high school graduate Some college or beyond Yards swam per 60-min workout Number of swim sessions in the past 30 days Average min per workout Average yards per workout
=0.28
=0.0104
Note: *P < 0.05 differing from group 1, post hoc Scheffe’s test.
swimming outcomes for swimmers concurrently taking statins. Our database included the 118 individuals who reported using a statin, and of those, 16 swimmers were also taking CoQ10.
Table IV presents these data. Those taking CoQ10 were not significantly different in age than those who did not take CoQ10. In spite of the small number of those taking CoQ10, using the t-test comparison, CoQ10 showed a trend towards a significant association with an increase in average yards swam per workout, although this was not significant after applying the Bonferroni-adjusted alpha value (P ≤ 0.0125). Additionally, the multivariate linear regression found that both younger age and CoQ10
Table III. Regression models for swim performance outcomes.
Model Model R2 Model P-value Variables Age (Beta, P-value) Gender (Beta, P-value) Race (Beta, P-value) Education (Beta, P-value) Statin use – group 1 current (beta, P-value) Statin use – group 2 currently on some other cholesterollowering drug or has high cholesterol but no drug therapy (beta, P-value)
Number of swim Length of time of workouts in the past each swim month workout 0.008 0.43 0.001, 0.97 −0.04, 0.34 0.02, 0.54 0.06, 0.09 −0.05, 0.22 −0.03, 0.40
0.02 0.06 −0.09, 0.05, 0.04, −0.02, −0.01, 0.02,
0.02 0.22 0.28 0.53 0.73 0.70
Note: Control group 3 was used as the comparator for statin use – group 1 and statin use – group 2.
Average yards swam per workout
Average yards swam/60-min workout
0.04
Journal of Sports Sciences Publication details, including instructions for authors and subscription information: http://www.tandfonline.com/loi/rjsp20
Statin use and self-reported swimming performance in US masters swimmers a
a
a
Kyle Terpak , Sally Guthrie & Steven Erickson a
College of Pharmacy, University of Michigan, Ann Arbor, United States Published online: 05 Aug 2014.
Click for updates To cite this article: Kyle Terpak, Sally Guthrie & Steven Erickson (2015) Statin use and self-reported swimming performance in US masters swimmers, Journal of Sports Sciences, 33:3, 286-292, DOI: 10.1080/02640414.2014.942688 To link to this article: http://dx.doi.org/10.1080/02640414.2014.942688
PLEASE SCROLL DOWN FOR ARTICLE Taylor & Francis makes every effort to ensure the accuracy of all the information (the “Content”) contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Terms & Conditions of access and use can be found at http:// www.tandfonline.com/page/terms-and-conditions
Journal of Sports Sciences, 2015 Vol. 33, No. 3, 286–292, http://dx.doi.org/10.1080/02640414.2014.942688
Statin use and self-reported swimming performance in US masters swimmers
KYLE TERPAK, SALLY GUTHRIE & STEVEN ERICKSON College of Pharmacy, University of Michigan, Ann Arbor, United States
Downloaded by [Michigan State University] at 12:10 28 February 2015
(Accepted 27 June 2014)
Abstract Exercise and treating hyperlipidaemia with statins are two integral components of the American Heart Association guidelines to reduce cardiovascular risk in adults. Since statins can cause myalgias and myopathies, they could affect the duration or intensity of an exercise regimen. To determine the impact of statin use in adult masters swimmers, a survey was distributed to examine the association between swimming performance and statin usage in adult swimmers (≥35 years). After excluding those with chronic diseases or taking drugs that reduce physical capacity, 749 swimmers (118 taking statins, 73 not taking statins to control elevated cholesterol and 558 controls) were included in a regression model to determine the factors significantly affecting the duration and intensity of swimming workouts. Age and gender were significantly (P ≤ 0.001) associated with the distance swam per 60 min. Younger, male swimmers completed more yards per 60-min workout. Use of statins was not significantly associated with yards swam per 60-min workout. Nor did statin usage affect the number of swim sessions per month or the length of swim session. Evidently, statins do not cause enough fatigue or pain in masters swimmers to require a decrease in the duration or intensity of workouts. Keywords: swimming, statin therapy, swim performance, coenzyme Q10
1. Introduction Heart disease is a major health problem worldwide and is especially prevalent in more affluent countries, such as the United States. To combat this disease, the American Heart Association (AHA) recently released guidelines for the treatment of cholesterol to reduce atherosclerotic cardiovascular risk in adults (Stone et al., 2013). In conjunction with recommendations for treatment of cholesterol, the AHA also released a guideline on lifestyle management to reduce cardiovascular risk that includes the recommendation for three to four 40-min sessions weekly of moderate- to vigorous-intensity physical activity (Eckel et al., 2013). One method of meeting the recommendations for physical activity that is gaining support in America is swimming. Swimming is the fourth most popular sports activity in the United States (US Census Bureau, 2012), while the United States Masters Swimming (USMS) organisation has a current membership of nearly 60,000 swimmers of all ability (United States Masters Swimming, 2013). Although prior studies indicate USMS members regard themselves as generally healthier than age-
matched people in the general US population, even this active group of individuals remain at risk for cardiovascular disease as they age (Guthrie, Erickson, & Lau, 2013). In addition to lifestyle management, one major strategy suggested by the AHA to reduce atherosclerotic cardiovascular risk is the use of the statin class of cholesterol-lowering drugs (Stone et al., 2013). Since 1998, the proportion of those aged 45 and older that use statins has increased dramatically (National Center for Health Statistics, 2011). While statins effectively lower cholesterol and are generally well tolerated, they are not without adverse effects. Reports of skeletal muscle pain (myalgias) and inflammation (myositis) or, rarely, necrosis (rhabdomyolysis) in individuals treated with statins are especially important for those who maintain an active lifestyle (Buettner, Davis, Leveille, Mittleman, & Mukamal, 2008; Krishnan & Thompson, 2010; Staffa, Chang, & Green, 2002; Tomlinson & Mangione, 2005). Additional evidence indicates that statin-induced myalgias are more frequent in older individuals and more physically active individuals (Mancini et al., 2011; Meador & Huey, 2010).
Correspondence: Steven R. Erickson, College of Pharmacy, University of Michigan, 428 Church Street, Ann Arbor 48109-1065, United States. E-mail: [email protected] © 2014 Taylor & Francis
Statins and performance in masters swimmers To determine the impact of statin use in adult masters swimmers, this study examined the association between the duration, distance and intensity of swimming workouts and statin usage in adult swimmers. This was done using data obtained from those who completed a survey sent to registered USMS members. We hypothesised that there would be an association between statin use and a decrease in distance, duration and intensity of swimming in USMS members even after adjustment for age and the presence of a chronic disease.
287
Table I. Survey questions regarding swimming workouts and medications. 1. Over the past 30 days, how many separate swimming workouts have you done? _______ times 2. If you swam at least once over the past 30 days, what was the average length of time of your workouts? _______ min 3. If you swam at least once over the past 30 days, what was the average distance swam per workout? _________ yards/metres 4. Below are listed common illnesses. Please read this list and check off an illness if a physician has ever diagnosed or told you that you have it: High blood pressure High blood cholesterol Diabetes
2. Methods
Downloaded by [Michigan State University] at 12:10 28 February 2015
2.1. Data collection The data used in this study were obtained from an Internet-based survey distributed to the USMS population in late 2010. The 54,949 swimmers registered with USMS in 2010 who were 21 years of age or older were invited to take part. The Sports Medicine Committee of USMS and the university’s Investigational Review Board gave approval for the study, and informed consent was obtained from all who participated in the survey. Swimmers were notified by a study announcement sent to all registered USMS members in October and November 2010 via an Internet newsletter. The newsletter contained a web link that directed the responder to a detailed overview of the project, including an informed consent. Those agreeing to take part were then directed via web link to the first page of the survey. No incentives were provided for participation in the survey. Individual-identifying data were not collected; all results were anonymous. The data collected included demographic data as well as self-reported characteristics of adult masters swimmers including the number of swim workouts per month, the length of time of each swim workout and average yards swam per workout session. Health-related variables including the presence of chronic diseases were also queried (Table I). Additionally, respondents were asked to document the use of prescription and non-prescription drugs and dietary supplements. Medication or supplement dose and frequency were not reported, nor was the duration of time that respondents had been taking these medications and supplements. Those who were taking the dietary supplement coenzyme Q10 (CoQ10) were identified because of this agent’s potential use as a treatment for statin-induced myalgias (Venero & Thompson, 2009). 2.2. Inclusion and exclusion criteria Although the database contained responses from swimmers aged ≥21 years, only those with ≥35 years of age were included in our analyses. The age threshold of 35 was
Heart failure Irregular heart beat or arrhythmia Coronary artery disease (ischemic heart disease) Cancer Arthritis Lung disease (asthma or other chronic lung disease) Depression Anxiety Migraine/recurrent headaches Allergies (eyes and nose) Stomach or intestinal ulcer (peptic ulcer disease) Osteoporosis Anaemia Stroke Thyroid problem Liver problem Chronic bronchitis 5. There are many other illnesses than those listed above that people can have. Please list below in your own words any other chronic condition that you may have that was diagnosed by a physician. (free text space was provided for as much information as the respondent chose to enter) 6. Please list ALL medications that you are currently taking, including those prescribed by your physician(s), any over-the-counter medications (such as aspirin) and any herbal products, dietary supplements such as creatine, or vitamin/mineral supplements: (free text space was provided for as many medications and supplements as the respondent chose to enter) 7. Of the medicines and supplements listed above, are there any that you think may be impairing your ability to exercise to the fullest extent? Yes
No
If yes, please record which one(s) and a brief description of the effect it is having
chosen due to the increased likelihood of receiving statin therapy, since routine assessment of cardiovascular risk factors, including serum lipid levels, begins at this age. Our analyses also excluded those reporting chronic diseases likely associated with reduced physical capacity, including multiple sclerosis, rheumatoid arthritis, osteoarthritis, lupus, fibromyalgia, spinal pain, chronic pain, gout, HIV, non-skin cancer, cystic fibrosis, Parkinson’s, Lyme disease,
288
K. Terpak et al.
Epstein–Barr and other neuropathies. In addition, those taking beta-blockers were excluded from further analyses, since this class of medications has been associated with decreased physical performance (Asplund, 2010). An adjusted value for distance swam per 60-min workout was used to judge swimming intensity. This was calculated by taking the average yards swam per workout, dividing this value by the average number of min per workout and then multiplying by 60.
deviation) or frequencies (percentage) for all demographic and swimming variables and compared using Student’s t-test for continuous variables and two-sided Fisher’s exact test for categorical variables. Since four ttests were conducted, the Bonferroni test was used to adjust alpha to ≤0.0125 for these comparisons. Multivariate linear regression models for each swimming performance outcome were conducted to determine the association between taking CoQ10 and swimming performance outcome measures, controlling for subject variables.
Downloaded by [Michigan State University] at 12:10 28 February 2015
2.3. Statistical methods 2.3.1. Sample size. Based on the data from the USMS, the average swim workout of USMS swimmers is approximately 2500 yards (Guthrie et al., 2013). Distance swam in workouts reflects overall endurance and is associated with a number of performance indicators for swimming. Therefore, yards swam per workout was selected as the primary measure of swimming performance to determine the sample size calculation. Assuming that a 500-yard difference in yards swam is a significant difference in performance (20% difference), using a standard deviation of 1000 yards, an alpha of 0.05 and power of 0.8, the sample size for each group was 50. 2.3.2. Statistical tests. The study sample was characterised using mean (standard deviation) or frequencies (percentage) for all demographic and swimming variables. Demographics and swimming performance variables were compared among three groups: (group 1) those currently taking statins, (group 2) those who have a history of elevated cholesterol but are not taking statins and (group 3) those not taking statins. Group 3 had no history of elevated cholesterol and is considered the control group. Analyses of variance (ANOVAs) were used for continuous variables and two-sided Chi-square or Fisher’s exact test for categorical variables. A P-value of 0.05 or less was used as a threshold for statistically significant differences. Since the comparison of demographic and swimming performance variables among the three groups required four different ANOVA tests, the alpha value was adjusted using Bonferroni test to ≤0.0125. Multivariate linear regression was used to determine the association between swimming performance outcomes (number of swim sessions per month, length of time of each swim session, average yards swam per workout session and average yards swam per 60 min) and the independent variables of demographics (age, gender, race and education) and statin usage (groups 1, 2 or 3). A secondary analysis of the potential effect of CoQ10 on swimming workout outcomes in those who concomitantly take a statin was conducted on those within the statin group (group 1). The CoQ10 and non-CoQ10 groups were characterised using mean (standard
3. Results The original sample contained 1054 completed surveys. After including only those aged 35 and older and excluding those with chronic diseases that may impair performance or who used beta-blockers, a total of 749 swimmers were included from the online survey data. Of those, 118 patients reported statin use (group 1), an additional 73 reported that they had been diagnosed with high blood cholesterol but they were not taking statins (group 2) and 558 were not taking statins and did not have high blood cholesterol (group 3). Population characteristics of the three groups are listed in Table II. Both age and gender were significantly different among the three groups, with statin users being older and more likely male. Regarding swimming performance outcomes, the post hoc Scheffe’s test identified that the control group (group 3) swam significantly more yards per workout and significantly more yards per 60 min than the statin users (group 1). Multivariate linear regressions were performed to determine the association between the specific swimming outcomes of interest and statin use groups, age, gender, race and education. Results of each model are shown in Table III. The multivariate linear regression indicated that statin use did not exhibit a significant impact on any swimming performance variables. However, age was significantly associated with the length of each workout, the average yards swam per workout and the average yards swam per 60-min workout (P = 0.02, P < 0.001 and P < 0.001, respectively). The average number of yards swam per workout session and the average yards swam per 60-min workout were significantly associated with both gender and age, with younger age and male gender being significantly associated with swimming longer distances per workout. Using this regression model, the statin use groups did not significantly predict any of the swimming performance variables after adjustment for age and gender. We also wanted to determine if the use of CoQ10 supplementation was associated with differences in
Statins and performance in masters swimmers
Table IV. Description of swimmers who took statins alone versus those taking statins and CoQ10.
Table II. Population characteristics. Group 1
Group 2
Group 3
Statin users, Non-statin Controls, mean (s) or users, mean mean (s) or frequency (s) or frequency (%) frequency (%) (%)
Downloaded by [Michigan State University] at 12:10 28 February 2015
Variable Age Gender Male Female Race Caucasian Minority Education Up to high school College/ beyond Yards swam per 60-min workout Number of swim sessions in the past 30 days Average min per workout Average yards per workout
N = 558
N = 73
62.7 (9.6)
54.3 (9.2)*
69 (59%) 48 (41%)
28 (39%) 44 (61%)
199 (36%) 358 (64%)
≤0.001
114 (97%) 3 (3%)
72 (99%) 1 (1%)
542 (98%) 13 (2%)
=0.85
1 (1%)
0 (0%)
4 (1%)
117 (99%)
73 (100%)
552 (99%)
2366.0 (592.8)
2461.4 (648.8)
13.7 (6.8)
13.7 (6.1)
P-value
52.3 (9.8)* ≤0.0001
=0.75
2614.6 =0.0114 (922.3)* 14.3 (6.4)
66.2 (18.1)
65.5 (17.5)
2470 (969) 2702 (1017)
2860 (1357)*
CoQ10 user, mean (s) or frequency (%)
Non-CoQ10 user, mean (s) or frequency (%)
N = 16
N = 102
P-value
63.9 (7.2)
63.3 (9.7)
0.79
11 (68.8) 5 (31.2)
57 (55.9) 44 (43.1)
0.42
15 (93.8) 1 (6.3)
100 (98.0) 2 (2.0)
0.36
0
6 (5.9)
1.00
16 (100)
96 (94.1)
2620.5 (595.9)
2445.5 (700.1)
0.35
13.7 (5.5)
13.9 (7.1)
0.89
69.4 (23.4)
62.3 (19.6)
0.19
3069 (1483)
2508.7 (963)
0.05
Variable
N = 118
62.8 (18.9)
289
=0.49
Age Gender Male Female Race White Non-white Education Up to high school graduate Some college or beyond Yards swam per 60-min workout Number of swim sessions in the past 30 days Average min per workout Average yards per workout
=0.28
=0.0104
Note: *P < 0.05 differing from group 1, post hoc Scheffe’s test.
swimming outcomes for swimmers concurrently taking statins. Our database included the 118 individuals who reported using a statin, and of those, 16 swimmers were also taking CoQ10.
Table IV presents these data. Those taking CoQ10 were not significantly different in age than those who did not take CoQ10. In spite of the small number of those taking CoQ10, using the t-test comparison, CoQ10 showed a trend towards a significant association with an increase in average yards swam per workout, although this was not significant after applying the Bonferroni-adjusted alpha value (P ≤ 0.0125). Additionally, the multivariate linear regression found that both younger age and CoQ10
Table III. Regression models for swim performance outcomes.
Model Model R2 Model P-value Variables Age (Beta, P-value) Gender (Beta, P-value) Race (Beta, P-value) Education (Beta, P-value) Statin use – group 1 current (beta, P-value) Statin use – group 2 currently on some other cholesterollowering drug or has high cholesterol but no drug therapy (beta, P-value)
Number of swim Length of time of workouts in the past each swim month workout 0.008 0.43 0.001, 0.97 −0.04, 0.34 0.02, 0.54 0.06, 0.09 −0.05, 0.22 −0.03, 0.40
0.02 0.06 −0.09, 0.05, 0.04, −0.02, −0.01, 0.02,
0.02 0.22 0.28 0.53 0.73 0.70
Note: Control group 3 was used as the comparator for statin use – group 1 and statin use – group 2.
Average yards swam per workout
Average yards swam/60-min workout
0.04
