Suicide accounts for almost 2% of the deaths in the world, though the rates between countries vary considerably. Socio-economic factors play a significant role in mental wellbeing and the rate of suicide. There is a strong relationship between socio-economic development and the age-sex structure of a population with changes in one being reflected in changes in the other. Age-sex changes in a population associated with socio-economic development are typically, falling birth rate and increased life expectancy which changes the age ratios between young and old. This study investigated the relationship between population structure and reported rate of suicide.

Data were provided by US Census Bureau and WHO. Non-parametric correlation (Spearman's rho) was used to examine the relationship between population structure and reported rate of suicide. Initially, median age was used to describe population. In order to take into account the complexity of population age structure the data were described and indexed using the UNEX30 algorithm.

A significant correlation was observed between the median age of the population and the rate of suicide (0.311; p < 0.001), but a higher level of correlation was observed between population structure and the reported rate of suicide (0.526; p < 0.001).

The findings support the hypothesis that the population age affects the reported rate of suicide, but more significantly, the age structure of the population shows a better relationship to the reported rate of suicide. This knowledge should be used to guide the direction of future research.