Differences in Health Outcomes between Men and Women: Biological, Behavioral, and Societal Factors

In the US and almost all other high-income countries, women live longer than men. As we enter a new era in which biomedical data are increasingly ubiquitous, it will serve us well to reenvision the research needed to understand the fundamental issues that drive differences in longevity and other health outcomes between men and women. The “Fourth Industrial Revolution” in which biological, physical, and information sciences are merging opens up important possibilities. The ability to measure the entire spectrum of information about the human biological, environmental, and behavioral condition will become both routine and relatively inexpensive: from genes to genomics; from clinical data to the electronic health record and insurance claims; from digital information about behavior and social interaction to geospatial referencing. In addition, because of ubiquitous access to cell phones and the Internet, these streams of information can be accessed in real time. Amid this revolution in the global scientific and social fabric, some of the most fundamental issues in the human condition are the differences in biology, behavior, and outcomes as a function of sex and gender. Sex differences begin with a difference in a single chromosome that leads to multiple obvious physical differences, but the evolution of societies and the changing roles of individuals within societies are also important. In parallel with variation in physical and biological function, gender identity provides a related but often complex construct with distinct biological and social influences. At the beginning of any such discussion, it is useful to acknowledge that beyond the X and Y chromosomes and direct biological structural manifestations, men and women overlap much more than they differ, so that differences should be understood as occurring within a broad spectrum rather than pointing to specific distinct differences. As far as we can tell, for most of human history, men …