Obesity, physical activity and the development of metabolic syndrome: the atherosclerosis risk in communities study

BACKGROUND: The objective of this study is to determine the impact of body weight and physical activity on the development of metabolic syndrome (MetS). DESIGN AND METHODS: We used the public use data from the Atherosclerosis Risk in Communities study. From the baseline cohort, we identified, as the study population, 9359 individuals who did not have MetS and who completed the second follow-up examination in 1993-1995. RESULTS: In 6 years of follow-up, 1970 individuals (25%) developed MetS. Compared with normal weight group [body mass index (BMI)<25 kg/m], the odds ratios [95% confidence interval (CI)] of incident MetS were 2.81 (95% CI: 2.50-3.17) and 5.24 (95% CI: 4.50-6.12) for the overweight (BMI: 25-30 kg/m) and the obese groups (BMI>or=30 kg/m), respectively. Compared with persons in the lowest quartile of leisure-time physical activity, the odds ratios (95% CI) of incident MetS were 0.80 (95% CI: 0.71-0.91) and 0.92 (95% CI: 0.81-1.04) for persons in the highest and the middle quartiles of leisure-time physical activity, respectively. Our results indicated that at any level of physical activity, there is a graded increase in the risk of incident MetS with an increase in BMI, in contrast to a lack of graded association between physical activity and the incidence of MetS in all categories of BMI. CONCLUSION: This study highlights the need to target obesity more than physical activity in preventing the development of MetS.