Obesity Research & Clinical Practice (2013) 7, e290—e296
ORIGINAL ARTICLE
2 years change of waist circumference and body mass index and associations with type 2 diabetes mellitus in cohort populations夽 Wenshu Luo a, Zhirong Guo a,∗, Xiaoshu Hu b, Zhengyuan Zhou c, Ming Wu d, Lijun Zhang a, Jingchao Liu a a
Department of Radiology & Public Health, Soochow University, SuZhou, JiangSu 215123, China Health Bureau of JiangSu Province, NanJing, JiangSu 210009, China c Center for Disease Control of ChangShu, Suzhou, JiangSu 215500, China d Center for Disease Control of JiangSu Province, NanJing, JiangSu 210009, China b
Received 4 September 2011 ; received in revised form 5 February 2012; accepted 8 February 2012
KEYWORDS Body mass index; Diabetes; Waist circumference
Summary Objective: Compare the association between 2 years change of waist circumference (WC) or body mass index (BMI) and incident type 2 diabetes mellitus (T2DM) in cohort populations. Methods: Prospective cohort study, based on a baseline investigation from 1999, we conducted the first follow-up for subjects whose follow time met 2 years, and the second follow-up for subjects whose follow time met 5 years. Two years change of WC or BMI was measured by the D-value between baseline and the first follow up values. The association between 2 years change of WC or BMI and incident T2DM were analyzed by using Poisson regression model. Results: Among 3461 participants without T2DM at baseline, 160 subjects developed T2DM during follow up period. Across quartiles of WC D-value, hazards ratio (HR) of incident T2DM increased, but there was no significant dose response relationship was found between BMI D-value and incident T2DM. Compared with subjects whose both WC and BMI were modified, there was no significant increase for T2DM risk in subjects whose WC was modified but BMI was not modified [HR(95%CI) = 1.66(0.70—3.97)], but the T2DM risk was significantly higher in subjects whose WC was not modified but BMI was modified [HR(95%CI) = 1.73(1.17—2.54)].
夽
Research fund: Scientific Research Fund of National Ministry of Health (WKJ 2004-2-014). Corresponding author at: Department of Epidemiology, School of Radiation Medicine & Public Health, Soochow University, SuZhou 215123, China. Tel.: +86 512 65880079; fax: +86 512 65884830. E-mail address: [email protected] (Z. Guo). ∗
1871-403X/$ — see front matter © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.orcp.2012.02.005
2 years change of waist circumference and body mass index
e291
Conclusions: WC change was a better predictor for incident T2DM than BMI change. Intervention programs designed to reduce WC through lifestyle modification, including physical activity and diet, may have significant public health significance in preventing incident T2DM. © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction Obesity is a major risk factor for incident T2DM [1—4]. Different anthropometric measures for obesity such as BMI and WC have been proposed to define overall obesity and abdominal obesity respectively. Although some studies [5—9] suggested that anthropometric measurements that describe central fat distribution are superior in predicting type 2 diabetes compared with measurements of general adiposity, however, there is controversy regarding which anthropometric measurements of obesity best conveys the highest risk for T2DM [10—14]. So it is important to clarify the role of overall and abdominal obesity in prediction of T2DM incidence. In cohort studies, obesity indicators would change because of life-style modification or targeted intervention, but few studies have focused on the association between obesity outcomes and WC or BMI change. Therefore, the aim of present study was to compare the magnitude of the association between 2 years change of WC or BMI and incident T2DM, based on data from program ‘‘Prevention of Multiple Metabolic Disorders and metabolic syndrome (MS) in Jiangsu Province’’ (PMMJS), in which we conducted twice follow-ups.
Materials and methods Study cohort The multi-stage sampling method was used in the present study. In stage one, we randomly selected three districts from 13 urban districts and nine counties from 52 counties in Jiangsu province based on the economic condition in different regions. In the second stage, one community (similar as a street district or a residential committee) from each city and one rural township from each county were sampled randomly, respectively. In the final stage, households were randomly chosen from the selected communities and townships; only one participant was randomly selected from each household, without replacement. Simple random sampling methods were used at each stage. The
local public health administrative institutes possess the household registration including address and telephone for all participants in order to track his or her health status easily in follow-up; individuals who suffered from the cancer, severe disability, and severe psychiatric disturbance were excluded. Data on demographic information, lifestyle risk factors, personal medical history and family history of T2DM for all participants were obtained using a standard questionnaire administered by trained staffs. All the measurements were performed during the morning of a health examination after the examinees fasted overnight. Automatical recording instrument was used to measure height and weight. Body mass index was calculated as weight in kilogram divided by the square of height in meters. Waist circumference was measured by the same physician at the umbilical level with the subjects standing and breathing normally during the physical examination. Blood samples were collected in the morning after at least 8 h of fasting. All plasma and serum samples were frozen at −80 ◦ C until laboratory testing. Plasma glucose was measured using an oxidase enzymatic method. Concentrations of HDL-cholesterol and triglycerides were assessed enzymatically on an automatic biochemistry analyzer (Hitachi Inc., Tokyo, Japan) using commercial reagents. The Friedewald equation [15] was used to calculate LDL-C from total cholesterol, HDL cholesterol, and triglycerides. All analysis was performed by the same lab. All the participants signed the informed consent form. They were also informed of their rights to withdraw at any stage or to prohibit their data from being used analyses. The investigation was only initiated after receiving written consent from the participants. This research was licensed by the ethical committee of Jiangsu Provincial Center for Disease Prevention and Control, China.
Follow-up survey During January 2002 and August 2003, there were only 5888 subjects whose follow-time met 2 years, and total 4582 participants (77.82%) received the first follow-up investigation. The contents and methods of the first follow-up investigation were
e292 the same as those at baseline. Amongst 4582 subjects who received the first follow-up investigation and whose follow-time met 5 years, total 3847 participants (83.96%) received the second follow-up investigation between March 2006 and November 2007. In this investigation, we mainly collected the data on the level of plasma glucose and information on incident T2DM. Those who did not attend twice follow-up examinations were similar to those who attended twice follow-ups in terms of age, sex, smoking, alcohol, family history of T2DM and metabolic variables. Total 3847 participants undergo twice follow-ups, after excluding subjects who were found to have T2DM at baseline (n = 332), cardiovascular disease (CVD) (n = 32), and BMI < 18.5 kg/m2 (n = 22), 3461 subjects (1406 males, 2055 females) were included in this analysis. The median duration of follow-up was 3.8 years from the first to the second follow-up.
Definition The cutoff values of waist circumference for abdominal obesity were 90 cm for male and 80 cm for female, which were in agreement with modification for Asian populations [16]; and abnormal BMI (overweight or overall obesity) was defined as BMI ≥ 25 kg/m2 [17]. The criteria [18] for the diagnosis of T2DM included a fasting glucose ≥126 mg/dl (7.0 mmol/l), or if hypoglycemic therapy (oral agents or insulin) had been started been started in the interim.
Statistical analysis The difference value (D-value) between the first follow-up and baseline was calculated to evaluate 2 years change of obesity indicators. D-value >0 meant that two indicators increased from baseline to the first follow-up, the greater the D-value was, the more WC or BMI increased. D-value 0.05
1 0.55(0.34—1.01) 0.72(0.45—1.16) 1.30(0.86—1.95) >0.05
2.7 4.3 4.7 6.9
1 1.41(0.86—1.92) 1.54(1.19—2.03)* 2.23(1.57—2.68)**
ORIGINAL ARTICLE
2 years change of waist circumference and body mass index and associations with type 2 diabetes mellitus in cohort populations夽 Wenshu Luo a, Zhirong Guo a,∗, Xiaoshu Hu b, Zhengyuan Zhou c, Ming Wu d, Lijun Zhang a, Jingchao Liu a a
Department of Radiology & Public Health, Soochow University, SuZhou, JiangSu 215123, China Health Bureau of JiangSu Province, NanJing, JiangSu 210009, China c Center for Disease Control of ChangShu, Suzhou, JiangSu 215500, China d Center for Disease Control of JiangSu Province, NanJing, JiangSu 210009, China b
Received 4 September 2011 ; received in revised form 5 February 2012; accepted 8 February 2012
KEYWORDS Body mass index; Diabetes; Waist circumference
Summary Objective: Compare the association between 2 years change of waist circumference (WC) or body mass index (BMI) and incident type 2 diabetes mellitus (T2DM) in cohort populations. Methods: Prospective cohort study, based on a baseline investigation from 1999, we conducted the first follow-up for subjects whose follow time met 2 years, and the second follow-up for subjects whose follow time met 5 years. Two years change of WC or BMI was measured by the D-value between baseline and the first follow up values. The association between 2 years change of WC or BMI and incident T2DM were analyzed by using Poisson regression model. Results: Among 3461 participants without T2DM at baseline, 160 subjects developed T2DM during follow up period. Across quartiles of WC D-value, hazards ratio (HR) of incident T2DM increased, but there was no significant dose response relationship was found between BMI D-value and incident T2DM. Compared with subjects whose both WC and BMI were modified, there was no significant increase for T2DM risk in subjects whose WC was modified but BMI was not modified [HR(95%CI) = 1.66(0.70—3.97)], but the T2DM risk was significantly higher in subjects whose WC was not modified but BMI was modified [HR(95%CI) = 1.73(1.17—2.54)].
夽
Research fund: Scientific Research Fund of National Ministry of Health (WKJ 2004-2-014). Corresponding author at: Department of Epidemiology, School of Radiation Medicine & Public Health, Soochow University, SuZhou 215123, China. Tel.: +86 512 65880079; fax: +86 512 65884830. E-mail address: [email protected] (Z. Guo). ∗
1871-403X/$ — see front matter © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
doi:10.1016/j.orcp.2012.02.005
2 years change of waist circumference and body mass index
e291
Conclusions: WC change was a better predictor for incident T2DM than BMI change. Intervention programs designed to reduce WC through lifestyle modification, including physical activity and diet, may have significant public health significance in preventing incident T2DM. © 2012 Asian Oceanian Association for the Study of Obesity. Published by Elsevier Ltd. All rights reserved.
Introduction Obesity is a major risk factor for incident T2DM [1—4]. Different anthropometric measures for obesity such as BMI and WC have been proposed to define overall obesity and abdominal obesity respectively. Although some studies [5—9] suggested that anthropometric measurements that describe central fat distribution are superior in predicting type 2 diabetes compared with measurements of general adiposity, however, there is controversy regarding which anthropometric measurements of obesity best conveys the highest risk for T2DM [10—14]. So it is important to clarify the role of overall and abdominal obesity in prediction of T2DM incidence. In cohort studies, obesity indicators would change because of life-style modification or targeted intervention, but few studies have focused on the association between obesity outcomes and WC or BMI change. Therefore, the aim of present study was to compare the magnitude of the association between 2 years change of WC or BMI and incident T2DM, based on data from program ‘‘Prevention of Multiple Metabolic Disorders and metabolic syndrome (MS) in Jiangsu Province’’ (PMMJS), in which we conducted twice follow-ups.
Materials and methods Study cohort The multi-stage sampling method was used in the present study. In stage one, we randomly selected three districts from 13 urban districts and nine counties from 52 counties in Jiangsu province based on the economic condition in different regions. In the second stage, one community (similar as a street district or a residential committee) from each city and one rural township from each county were sampled randomly, respectively. In the final stage, households were randomly chosen from the selected communities and townships; only one participant was randomly selected from each household, without replacement. Simple random sampling methods were used at each stage. The
local public health administrative institutes possess the household registration including address and telephone for all participants in order to track his or her health status easily in follow-up; individuals who suffered from the cancer, severe disability, and severe psychiatric disturbance were excluded. Data on demographic information, lifestyle risk factors, personal medical history and family history of T2DM for all participants were obtained using a standard questionnaire administered by trained staffs. All the measurements were performed during the morning of a health examination after the examinees fasted overnight. Automatical recording instrument was used to measure height and weight. Body mass index was calculated as weight in kilogram divided by the square of height in meters. Waist circumference was measured by the same physician at the umbilical level with the subjects standing and breathing normally during the physical examination. Blood samples were collected in the morning after at least 8 h of fasting. All plasma and serum samples were frozen at −80 ◦ C until laboratory testing. Plasma glucose was measured using an oxidase enzymatic method. Concentrations of HDL-cholesterol and triglycerides were assessed enzymatically on an automatic biochemistry analyzer (Hitachi Inc., Tokyo, Japan) using commercial reagents. The Friedewald equation [15] was used to calculate LDL-C from total cholesterol, HDL cholesterol, and triglycerides. All analysis was performed by the same lab. All the participants signed the informed consent form. They were also informed of their rights to withdraw at any stage or to prohibit their data from being used analyses. The investigation was only initiated after receiving written consent from the participants. This research was licensed by the ethical committee of Jiangsu Provincial Center for Disease Prevention and Control, China.
Follow-up survey During January 2002 and August 2003, there were only 5888 subjects whose follow-time met 2 years, and total 4582 participants (77.82%) received the first follow-up investigation. The contents and methods of the first follow-up investigation were
e292 the same as those at baseline. Amongst 4582 subjects who received the first follow-up investigation and whose follow-time met 5 years, total 3847 participants (83.96%) received the second follow-up investigation between March 2006 and November 2007. In this investigation, we mainly collected the data on the level of plasma glucose and information on incident T2DM. Those who did not attend twice follow-up examinations were similar to those who attended twice follow-ups in terms of age, sex, smoking, alcohol, family history of T2DM and metabolic variables. Total 3847 participants undergo twice follow-ups, after excluding subjects who were found to have T2DM at baseline (n = 332), cardiovascular disease (CVD) (n = 32), and BMI < 18.5 kg/m2 (n = 22), 3461 subjects (1406 males, 2055 females) were included in this analysis. The median duration of follow-up was 3.8 years from the first to the second follow-up.
Definition The cutoff values of waist circumference for abdominal obesity were 90 cm for male and 80 cm for female, which were in agreement with modification for Asian populations [16]; and abnormal BMI (overweight or overall obesity) was defined as BMI ≥ 25 kg/m2 [17]. The criteria [18] for the diagnosis of T2DM included a fasting glucose ≥126 mg/dl (7.0 mmol/l), or if hypoglycemic therapy (oral agents or insulin) had been started been started in the interim.
Statistical analysis The difference value (D-value) between the first follow-up and baseline was calculated to evaluate 2 years change of obesity indicators. D-value >0 meant that two indicators increased from baseline to the first follow-up, the greater the D-value was, the more WC or BMI increased. D-value 0.05
1 0.55(0.34—1.01) 0.72(0.45—1.16) 1.30(0.86—1.95) >0.05
2.7 4.3 4.7 6.9
1 1.41(0.86—1.92) 1.54(1.19—2.03)* 2.23(1.57—2.68)**
