Does Sex Matter in Musculoskeletal Health?<sbt aid="1021074">The Influence of Sex and Gender on Musculoskeletal Health<cross-ref type="fn" refid="fn1">*</cross-ref></sbt>

Disease prevalence rates differ for men and women; this comes as news neither to physicians nor to laypersons. Likewise, women's life expectancies differ from those of men. Among some populations, this difference is dramatic. For example, the National Center for Health Statistics reports that, in 2001, the life expectancy of a black American woman was 75.5 years and that of a black American man was just 68.6 years1. Worldwide, women live, on the average, between four and ten years longer than men do. Historically, studies that have examined differences in men's and women's health have assumed that women were “little men,”2 and were limited to topics associated with the reproductive system, e.g., breast cancer and menopause, and that sex differences outside the reproductive system could be explained by variations in height, weight, body fat percentage, etc. Until the past decade, it was not possible to explore the basis of the differences in disease prevalence and morbidity and mortality between men and women at the genetic and cellular levels. Today, however, emerging information from such studies provides a compelling case for the existence of innate, and heretofore unexamined, differences between men and women. Medical researchers in virtually every discipline are now beginning to realize that every organ in the body, not just those related to reproduction, is capable of responding differently on the basis of sex, and that these different responses result from chromosomes as well as hormones. In the Institute of Medicine report3, Exploring the Biological Contributions to Human Health: Does Sex Matter?, “sex” is defined as “the classification of living things, generally as male or female according to their reproductive organs and functions assigned by the chromosomal complement” and “gender” is defined as “a person's self-representation as male or female, or how that person …