Males and females--some vital differences

Area of Science:

• Demography
• Population Studies
• Epidemiology

Background:

• The human sex ratio at birth typically favors males, but this ratio shifts dramatically with age.
• Significant demographic imbalances between males and females are observed in older populations.
• Understanding these sex ratio dynamics is crucial for public health and social planning.

Purpose of the Study:

• To quantify the age-specific sex ratio variations in England and Wales.
• To investigate the underlying causes, specifically mortality and migration patterns, driving these sex ratio disparities.
• To examine historical trends in sex ratio imbalances throughout the 21st century.

Main Methods:

• Analysis of national vital statistics and census data for England and Wales.
• Age-period-cohort modeling to assess demographic changes.
• Comparative analysis of male and female mortality rates and migration flows.

Main Results:

• The study quantifies the divergence of the sex ratio across different age groups.
• Identifies key periods and causes contributing to the increasing female majority in older age cohorts.
• Highlights significant differences in mortality trajectories and migration patterns between sexes.

Conclusions:

• The observed sex ratio imbalance is primarily driven by sex-differentiated mortality rates, with women exhibiting lower mortality at older ages.
• Migration patterns also contribute to regional and age-specific sex ratio variations.
• These findings provide essential data for understanding population aging and sex-specific health outcomes.