Women's health: explaining the trend in gender ratio in Iran over half a century (1956-2006)

Objectives: Changes in gender ratio generally reflect differences in mortality rates in men and women. Female mortality rates, on the other hand, can be used as an index of the trends in women's health. This study looks at the trend in the population gender ratio from 1956 to 2006, with a focus on analysing mortality rates and hence the overall health of Iranian women over the last 50 years.

Study design: Cohort-type analysis using data from the last five population censuses in Iran.

Methods: Data were used to calculate gender ratios and analyse their trends over the 50-year period from 1956 to 2006.

Results: According to the 1956 Census, there were 98 men for every 100 women in the 25-34 years age group (male:female ratio=0.98). In the next census, conducted 10 years later (1966), the gender ratio increased to 121 in the 39-44 years age group. The discrepancy increased in later censuses; this trend indicates that mortality in the 25-34 years age group was significantly higher in 1956-1966 compared with subsequent decades. The social and economic crises of the 1940s probably left women of reproductive age exceptionally vulnerable to a wide range of adverse health outcomes. The fact that the trend ceased in 1976 with no further increase in the gender ratio may be due to improving social conditions and greater effectiveness of healthcare programmes directed at women.

Conclusion: As life expectancy is calculated on the basis of the conditional probability of death over specific intervals, the apparent discrepancy between the current gender ratios and life expectancy data may be due to higher female death rates before 1976.