Few studies have examined whether sex differences in mortality are associated with
different distributions of risk factors or result from the unique relationships between
risk factors and mortality for men and women. We extend previous research by systematically
testing a variety offactors, including health behaviors, social ties, socioeconomic
status, and biological indicators of health. We employ the National Health and Nutritional
Examination Survey III Linked Mortality File and use Cox proportional hazards models
to examine sex diferences in adult mortality in the United States. Our findings document
that social and behavioral characteristics are key factors related to the sex gap
in mortality. Once we controlfor women's lower levels of marriage, poverty, and exercise,
the sex gap in mortality widens; and once we control for women 's greater propensity
to visit with friends and relatives, attend religious services, and abstain from smoking,
the sex gap in mortality narrows. Biological factors-including indicators of inflammation
and cardiovascular risk-also inform sex differences in mortality. Nevertheless, persistent
sex differences in mortality remain: compared with women, men have 30% to 83% higher
risks of death over the follow-up period, depending on the covariates included in
the model. Although the prevalence of risk factors difers by sex, the impact of those
risk factors on mortality is similar for men and women.