Public Health Nutrition: 13(9), 1389–1394 doi:10.1017/S1368980010000108 Factors related to obesity among Iranian men: results from the National Health Survey Enayatollah Bakhshi 1,2 , Kazem Mohammad 1, *, Mohammad R Eshraghian 1 and Behjat Seifi 3 1 Department of Biostatistics, School of Public Health and Institute of Public Health Research, Tehran University of Medical Sciences, Tehran 141556446, Islamic Republic of Iran: 2 Department of Statistics and Computer, University of Welfare and Rehabilitation Sciences, Tehran, Islamic Republic of Iran: 3 Department of Physiology, Medicine School, Tehran University of Medical Sciences, Tehran, Islamic Republic of Iran Submitted 15 May 2009: Accepted 29 December 2009: First published online 4 May 2010 Abstract Objective: To our knowledge, only a few Iranian studies have investigated factors associated with obesity among men. The aims of the present study were to explore the associations between sociodemographic factors, smoking and obesity in Iranian men and compare these associations between Iranian men and women. Design: We used data from the National Health Survey in Iran. A generalised estimating equations model included 11 697 men and 14 854 women aged 20–69 years (12 850 households). Body weight and height were objectively measured. BMI was calculated as kg/m 2 , and subjects were classified into obese (BMI $ 30 kg/m 2 ) and non-obese (BMI , 30 kg/m 2 ). Results: Among men, adjusted obesity OR were 0?62 (95% CI 0?52, 0?74), 1?09 (95 % CI 0?90, 1?32), 1?003 (95 % CI 1?00, 1?007) and 0?57 (95 % CI 0?40, 0?81) for smokers, married, economic index and active workforce groups, respectively. Using low education as the reference group, the obesity OR for men were 1?06 (95% CI 0?89, 1?26) and 0?75 (95% CI 0?57, 0?99) for the moderate and high education groups, respectively. Using rural as the reference group, the obesity OR was 1?87 (95% CI 1?56, 2?26) for urban men. Conclusions: Our findings may point towards a better understanding of the social and cultural mechanisms of obesity in Iranian men. The above sociodemographic factors are large contributors to obesity and provide the greatest opportunity for actions and interventions designed for prevention and treatment. Keywords Generalised estimating equation Obesity Odds ratio Iranian men The obesity epidemic has become a worldwide pheno- menon in recent years (1,2) . Nearly half a billion of the world’s population is now considered to be overweight or obese (3) . In 2003–2004, approximately 32% of the US adult population was obese (4) . Obesity in men is con- sidered a major problem in Europe and the prevalence of obesity has increased by 10–40% in the past 10 years (5) . Almost one-third of adult Canadians are at increased risk of disability, disease and premature death due to obesity (6) . In 2001, 58% of Australian men and 42% of Australian women were classified as overweight or obese (7) . Obesity is not only classified as a disease in its own right, but also has been reported to be a risk factor for CVD, diabetes, hypertension, some cancers and other diseases (8–15) . Obesity is caused by many factors. Most studies have investigated the relationship between sociodemographic factors and obesity. One potential predictor could be age (16–19) . Another predictor is socio-economic status that has shown an inverse relation with obesity among women, but weaker and less consistent among men (20–23) . In low-income countries, obesity is more common among middle-aged women, people of higher socio- economic status and people living in urban commu- nities (19,24,25) . Molarius et al. (22) found that low education was associated with a higher BMI (BMI was calculated as kg/m 2 ) in about half of the male and in almost all of the female populations of the WHO MONICA Project. Although the association of obesity with smoking has been analysed in many studies, the findings are not consistent (26–31) . A study that had a sample size sufficient to explore factors associated with obesity among Iranian men has not been carried out in Iran. The primary aim of the present study was to examine the relationship between sociodemographic factors, smoking and obesity among men by using cross-sectional data from the National *Corresponding author: Email mohamadk@tums.ac.ir r The Authors 2010