Increasing BMI and waist circumference and prevalence of obesity among adults with Type 2 diabetes: the National Health and Nutrition Examination Surveys

Objective: Obesity remains one of the most important modifiable risk factors for the prevention of Type 2 diabetes and its related comorbid conditions. The aim of this study was to examine trends in average body mass index (BMI), waist circumference, and obesity prevalence among adults with and without Type 2 diabetes. Methods: Information on BMI and waist circumference among 4162 adults with and 40,376 adults without Type 2 diabetes was obtained from the National Health and Examination Surveys completed during years 1976-2006. Mean BMI, waist circumference and prevalence of total obesity (BMI >= 30 kg/m(2)) and obesity stage III (BMI >= 40 kg/m(2)) were determined by survey periods after adjustment for the survey period weights and age standardization to the US 2000 Census. Means and proportions between first and last survey periods were compared using Z scores. Results: During this 20-year period, mean BMI increased from 29.2 kg/m(2) to 34.2 kg/m(2) among adults with Type 2 diabetes and from 25.2 kg/m(2) to 28.1 kg/m(2) among adults without diabetes (P<.0001 for both comparisons). Mean waist circumference increased substantially in all groups. Among adults with and without Type 2 diabetes, total obesity increased by 58% and 136%, respectively, while Class III obesity increased by 141% and 345%, respectively (P<.0001 for all comparisons). Conclusions: Obesity prevalence is rising rapidly among adults with and without Type 2 diabetes. This has important implications for the likely growth of the population with Type 2 diabetes and diabetes related comorbid conditions. (C) 2010 Elsevier Inc. All rights reserved.