Socioeconomic inequality in prevalence of cigarette and Water-pipe smoking among Iranian adults: A blinder- Oaxaca decomposition Analysis

Background: To assess the association between socioeconomic inequality and the prevalence of tobacco smoking among Iranian adults in 2010. Methods: Data from the fifth national STEPS survey (WHO STEPwise approach to NCD Surveillance) were analyzed. A Blinder-Oaxaca decomposition method was applied to assess the association between socioeconomic inequality and the prevalence of daily cigarette and water pipe (WP) smoking among Iranian men and women. Results: From 10,615 participants in the survey, 4,203 (39.5%) participants appeared to be in the first and fifth quintiles of socioeconomic status (SES). For men, the prevalence of daily cigarette smoking was higher among those with low SES (23.1%) than those with high SES (11.1%) (P<0.001). The observed difference was mainly attributed to the educational level (8.6%). We found no significant difference in high compared to low SES women for cigarette smoking (P value= 0.881). Although there was no difference between high and low SES men for daily WP smoking, low SES women had a higher prevalence of WP smoking (4.4%) than high SES women (1.3%) (P value=0.027). Education level was the major factor (3.3%) to explain the corresponding difference. The difference in WP smoking in high and low SES men was not statistically significant (P value= 0.199). Conclusion: Cigarette smoking in men and WP smoking in women are associated with SES in Iran. Education was the main factor explaining the differences in the prevalence of cigarette and WP smoking in Iranian men and women. Results from this study must be considered as a pivotal basis for designing a tobacco control program at national and sub-national levels.