Background: Insulin resistance is an underlying mechanism of metabolic syndrome. We attempted to determine the association between physical activity and insulin resistance in Iranian adults.
Methods: The data of the third national Surveillance of Risk Factors of Non-Communicable Diseases (SuRFNCD-2007) in Iran were used. We ran the Global Physical Activity Questionnaire (GPAQ) over a nationally representative sample of 3101 adults. Total physical activity (TPA) was calculated using metabolic equivalents (MET) for intensity of physical activities. Insulin resistance was measured by the homeostasis model assessment of insulin resistance (HOMA-IR).
Results: When physical activity was classified into high, moderate, and low categories, HOMA-IR values significantly increased from the high category to the moderate and low categories (p<0.01). After adjustment for age, area of residence, smoking, and body mass index (BMI), TPA (r=-0.26, p<0.01 in males and r=-0.21, p<0.01 in females), duration of vigorous-intensity activity (r=-0.28, p<0.01 in males and r=-0.18, p=0.01 in females), duration of moderate-intensity activity (r=-0.16, p=0.01 in males and r=-0.17, p<0.01 in females), and the time spent on sedentary behaviors (r=0.16, p=0.01 in males and r=-0.22, p<0.01 in females) were significantly correlated to HOMA-IR. The prevalence of physical inactivity increased linearly with increasing HOMA-IR quintiles.
Conclusions: Our findings indicate a significant relationship between physical inactivity and insulin resistance. For communities in a transition phase of lifestyle, encouraging physical activity may help prevent insulin resistance and its adverse consequences.