Background: Physical activity has shown to prevent type diabetes 2. However, the type, intensity and amount of effective physical activity as well as individuals' needs according to level of their risk for type 2 diabetes have not been clarified comprehensively. This study investigated a relation between moderate aerobic physical activity ≥150 minuets/week with decreased risk of type 2 diabetes among obese and non-obese residents of south of Tehran, Iran.
Methods: This study, which was a part of the Cardiovascular Risk Factors Survey in Tehran population Lab region, was designed and conducted based on MONICA/WHO project. Totally, 1552 adult inhabitants of 17th district of Tehran were enrolled in this cross-sectional study. Physical activity was assessed by MONICA Optional Study of Physical Activity questionnaire. Diabetes was defined as a history of a prior diagnosis of diabetes or fasting serum glucose ≥126 mg/dl. All data analyses were conducted using SPSS 17 software for Windows
Results: In a multivariate model, moderate aerobic physical activity ≥150 minuets/week was significantly associated with decreased risk of type 2 diabetes in all and non-obese subjects [OR= 0.56; 95%CI: 0.35-0.91 and OR= 0.50; 95%CI: 0.26-0.94, respectively]. There was no significant relation between the physical activity and type 2 diabetes risk in obese subjects [OR=0.64; 95%CI: 0.30-1.39].
Conclusion: Moderate aerobic physical activity ≥150 minuets/week was significantly associated with decreased risk of type 2 diabetes in non-obese people and could be an acceptable exercise goal for these individuals. However, obese people should be investigated more to produce a tailored exercise guideline to this population at high risk of type 2 diabetes.
Keywords: Physical activity, Diabetes mellitus, Iran
Type 2 diabetes is the common type of diabetes. In the United States, it has reached epidemic levels with affected 20.6 million people (1, 2). The prevalence of diabetes has been estimated at 8.7% in the Iranian population aged 15-64 yr (3). Increased number of newly diagnosed type 2 diabetics along with its complications has made a major public health concern in industrialized and developing countries (4-8). Genetic susceptibility, environmental and lifestyle factors like obesity, central adiposity, unhealthy diet, and physical inactivity are risk factors of type 2 diabetes (9, 10).
There is evidence that in spite of national educational efforts to decrease sedentary behavior, 24% of American adults do not participate in leisuretime activity (11). Results from cross-sectional studies have shown an inverse relation between moderately intense physical activity and type 2 diabetes (12, 13). Prospective studies have also found that moderate to high level physical activity can prevent type 2 diabetes (14-19). In addition, some clinical trials have shown that lifestyle modifications such as increase in physical activity, weight reduction, and balanced diet can prevent type 2 diabetes (20-23). In total, evidence confirms an effective role for physical activity in prevention of type 2 diabetes. Nevertheless, several main issues remain to be resolved. The type, intensity, and amount of physical activity that can be efficient should be verified. Another point is that whether physical activity alone can prevent diabetes. In addition, it should be considered whether an individuals' susceptibility for developing type 2 diabetes can determine their requirements for physical activity. Various studies have shown that aerobic physical activity reduces the risk of developing type 2 diabetes (20, 21, 23-27). In a systematic review, it was found that moderate intensity physical activity was associated with reduced risk of diabetes even after adjustment for body mass index (BMI); although this relation was attenuated (28). Some interventional trials have shown that 150 min moderate physical activity per week could decrease risk of progression to diabetes in adults with impaired glucose tolerance or at high risk of cardiovascular disease independent of weight loss, although this level of activity did not preclude development of diabetes in all cases (29). …