a 23-year analysis of dependency ratio in rural population in fars province during 1990-2012: a trend analysis study

background: the dependency ratio (dr) is defined as the ratio of the non-working population to the economically active population. dependency ratio is calculated by the sum of population under fifteen years and over 65 years divided by 15-64 year old population. the interpretation of dr variation gives us the impact of health care services and some reproductive interventions. this study analyzed a 23-year dr trend in rural population of fars province and the effect of some fertility variables on it.   methods: in this study, using data from vital horoscope and regression analysis, we analyzed a 23-year period of dr and some fertility indicators.   results: the total dr significantly declined from 102.5% in 1990 to 41.4% in 2012 (p<0.001). most of this reduction is attributed to reduction in young dr. old dependency ratio (population of 65 years and more) was significantly growing (p<0.035). number of rural health house, family planning coverage, total fertility rate and general fertility rate was significantly associated with total dependency ratio (p<0.009).   conclusion: we passed the first stage of demographic transition, i.e. young dependency ratio declining. but the old dependency ratio slowly increased; it is recommended that the health care services should be promoted in future, especially services for old age people.