Mortality data from the Baja California peninsula of Mexico

A consistent finding from contemporary Western societies is that women
outlive men. However, what is unclear is whether sex differences in
survival are constant across varying socio-ecological conditions. We test
the universality of the female survival advantage with mortality data from
a 19th century population in the Baja California peninsula of Mexico. When
examined simply, we find evidence for a male-biased survival advantage.
However, results from Cox regression clearly show the importance of age
intervals for variable survival patterns by sex. Our key findings are that
males: 1) experience significantly lower mortality risk than females
during the ages 15-30 (RR = 0.69), 2) are at a significantly increased
risk of dying in the 61+ category (RR =  1.30), and 3) do not
experience significantly different mortality risk at any other age
interval (0-14, 31-45, 46-60). We interpret our results to stem from
differing intrinsic and extrinsic risk-factors for sex-biased mortality
across age intervals, highlighting the relevance of a lifecourse approach
to the study of survival advantage. Ultimately, our results make clear the
need to more broadly consider variability in mortality risk factors across
time and place to allow for a clearer understanding of human survival
differences.