how within-city socioeconomic disparities affect life expectancy? results of urban heart in tehran, iran

background :there is substantial lack of knowledge about the role of socioeconomic status (ses) indicators on life expectancy (le) within-cities, especially within mega-cities. we aimed to investigate the disparities of le within city districts of tehran, iran, and specify how ses inequalities play role on le.   methods : the death and population data for 2010 by different age, gender, and residency district were obtained from the main cemetery of tehran and statistical centre of iran, respectively. age-specific mortality rates and consequently le were calculated for all 22 districts by different genders. finally, based on the results of first tehran's urban health equity assessment and response tool (urban heart) project in 2008, the influence of social classes (scs), total costs, and education indicators were analyzed on le at birth (e0).   results : the e0 for total males and females in tehran were calculated as 74.6 and 78.4 years for 2010, respectively. the maximum le of 80 years was observed in females of northern part with higher ses, and the minimum e0 of 72.7 years observed in males of southern part with lower ses. the e0 gender gap among districts was 5.5 years for females and 3.7 years for males. the highest and lowest mean of e0 observed in sc1 (highest class) and sc5 (lowest class), were 77.6 and 76.0 years, respectively. the lowest mean of e0 observed in the first group of total costs indicator and was 76.2 years. in addition, the lowest observed mean of e0 was in the first category of education indicator (illiterate) and was 76.0 years.   conclusion : results indicate substantial disparities in le within city districts. this confirms that ses disparities within-cities would have direct influences on le.