Differences in sociodemographic, health-related, and psychological factors in users and nonusers of nutritional supplements in fitness club participants in Tehran, Iran

Nutritional supplement (NS) use has increased among the general population, athletes, and fitness club participants and has become a widespread and acceptable behavior. The objective of this study was to determine the differences in sociodemographic, health-related, and psychological factors between NS users and nonusers. A case-control study design was used, whereby participants included 147 NS users (cases) and 147 nonusers (controls) age 18 yr and above who exercised at least 3 d/wk in 24 fitness clubs in Tehran. A self-administered pretested and validated questionnaire was used to collect data. The results showed that on average, NS users were younger (29.8 ± 9.5 yr) than nonusers (35.5 ± 12.2 yr). Logistic-regression analysis showed that NS use was significantly associated with moderate or high physical activity level (PAL), smoking, gender, eating attitude, and age. In conclusion, NS users were more likely to be female, younger, and smokers; to have moderate or high PAL; and to be more prone to eating disorders than nonusers.