Absolute and relative educational inequalities in obesity among adults in Tehran: Findings from the Urban HEART study-2

BACKGROUND: The prevalence of obesity is increasing in Iran. Previous studies showed mixed results in relation to association between socioeconomic status and obesity in the country. The current study aimed to examine educational inequalities among adults in Tehran in 2011. METHOD: Data on 90,435 persons 18 years and older from Urban Health Equity Assessment and Response Tool (Urban HEART-2) were analyzed. The Slope Index of Inequality (SII) and the Relative Index of Inequality (RII) were used for assessing educational inequalities in obesity. These measures were quantified using generalized linear models for the binomial family adjusted for sex and age. Subgroup analysis was conducted across sex, age groups and the 22 districts of Tehran. RESULTS: Both SII and RII showed substantial educational inequalities in obesity in favour of more educated adults [RII and SII (95% CI were equal to 2.91 (2.71-3.11) and 0.12 (0.12-0.13)), respectively]. These educational inequalities were persistent even after adjusting for employment, marital status and smoking. Subgroup analysis revealed that educational inequalities were more profound among women. While among men educational inequalities were generally increasing with age, an inverse trend was observed among women. Educational inequalities were observed within all 22 districts of Tehran and generally there were no statistically significant differences between districts. CONCLUSION: An inverse association between education and obesity was observed in the current study. To decrease educational inequalities in Tehran, priority should be given to younger women and older men. Further analyses are needed to explain these inequalities