Aims: To determine the prevalence and associations of general and central obesity in adults residing in district 13 of Tehran and to examine the associations of obesity with certain factors.
Design: Population-based cross sectional study.
Setting: Tehran, the capital of Iran.
Subjects: A total of 9984 subjects (4164 men and 5820 women) aged 20-70 years.
Methods: Demographic data were collected and anthropometric indices including weight, height, and waist and hip circumference were measured, according to standard protocols. Dietary intake was assessed by means of two 24-hour dietary recall forms. To determine the prevalence and association of general and central obesity, the suggested cut-off for Tehranian people, adjusted for their age group, was used. A body mass index (BMI) of > or =24 for men and > or =25 for women was used to determine the characteristic of obesity. Central obesity was determined as a waist-hip ratio (WHR) of > 0.86 for men and WHR > or = 0.78 for women. To determine the associations between general and central obesity and other factors, logistic regression was used.
Results: The means of BMI, waist circumference (WC), and WHR were 25.8 +/- 4.1 kg/m2, 88.3 +/- 11.4 cm, and 0.91 +/- 0.07 in men and 27.3 +/- 5.4 kg/m2, 87.5 +/- 12.9 cm, and 0.83 +/- 0.08 in women, respectively. Obesity and central obesity were higher in women than in men; 67% vs. 29% for obesity and 93% vs. 74.1% for central obesity, respectively. Illiteracy (OR = 1.65; 95% CI = 1.13-2.41 in men; OR = 1.87, 95% CI = 1.59-2.21 in women), marriage (OR = 3.84, 95% CI = 3.63-4.29 in men; OR = 3.20, 95% CI = 3.63-4.19 in women), and very low physical activity (OR = 1.35, 95% CI = 1.09-1.53 in men; OR = 1.39, 95% CI = 1.10-1.76 in women) were factors associated with obesity. The risk of being centrally obese for men in the fourth quartile of legumes intake was lower than men in other quartiles (p < 0.05). Women in the first quartile of dairy consumption had the highest risk of being generally and centrally obese (OR = 2.16, 95% CI = 1.72-2.48 for general obesity and OR = 3.01, 95% CI = 2.36-3.67 for central obesity). The risk of obesity for women in the fourth quartile of energy and saturated fatty acid consumption was higher than for those in the first quartile (OR = 2.69, 95% CI = 2.39-3.11 for energy and OR = 1.36, 95% CI= 1.10-1.64 for saturated fatty acids). The risk of being centrally obese was higher for women in the first quartile of protein intake compared with women in the fourth quartile (OR = 1.71, 95% CI = 1.02-2.32).
Conclusions: The results from this national population-based study in Iran show high prevalence of obesity in Tehranian adults. The strong associations between obesity and certain life style factors confirm the necessity of multifactorial intervention.