Sex and gender factors in medical studies: implications for health and clinical practice.

Males and females have different patterns of illness and different life spans . . . Understanding the bases of these sex-based differences is important to developing new approaches to prevention, diagnosis, and treatment. THE US CENSUS BUREAU PROJECTS that the US population will have increasing numbers of women in the next decades and a greater proportion of the population will be elderly and nonwhite persons. Women are the major consumers of health care, the major consumers of prescription drugs, and the primary decision makers about health care for their families. As attention is directed to improving health of and health care for women, sex and gender differences in research design and regulatory policies interface with clinical practice. An interdisciplinary, inclusive approach to health care based on sexand gender-specific data is sought by consumers of health care, especially women. Understanding the role of sex in health and disease begins with consistency in medical literature of the terms sex and gender. The recent Institute of Medicine report Exploring the Biological Contributions to Human Health: Does Sex Matter? provides clarification of these terms in its discussions of differences between men and women. The term sex is used when differences are primarily biological in origin and may be genetic or phenotypic (genetic or physiological characteristics of being a man or woman), and gender is used when referring to social and cultural influences based on sex (BOX). There is a long history of advocacy for health care specific to women in the United States, dating as far back as the Popular Health Movement of the 1800s. The efforts of women in medicine, government, and advocacy in the 1980s propelled improvement of women’s health through biomedical research and were primarily based in the public policy realm, relating to the inclusion of women in clinical studies. Results of these efforts included major revisions in policies for research as well as expanding what constitutes women’s health. This goes beyond reproductive health and addresses women’s health across their lifespan. As the women’s health movement focused on the inclusion of women in clinical research to provide basic fundamentals for gender-appropriate health care, there has also been realization that sex and gender comparisons are important factors in research design. Such research has valuable implications for the practicing physician in the care of both female and male patients. Not only may physicians need to make diagnostic and treatment decisions based on the sex of the patient, but they will also need to respond to gender differences in how women and men approach their physicians, their own health, and how they communicate their health concerns.