Editorial for the special issue on behavior change, health, and health disparities 2017.

This Special Issue of Preventive Medicine (PM) is the 4th in a series on behavior change, health, and health disparities, a topic of critical importance to improving U.S. population health. The U.S. ranks near the bottom on measures of population health relative to other industrialized countries despite spending orders of magnitude more on health care than any other nation. Population health experts agree that the area of personal behavior, or lifestyle, such as substance abuse, physical inactivity/obesity, and non-adherence with medical regimens is the single largest contributor to this situation. These unhealthy behavior patterns disproportionately impact economically disadvantaged populations and other vulnerable populations and represent a major contributor to health disparities. Thus, behavior change represents an essential step in improving population health generally and curtailing health disparities more specifically. While perhaps more severe in the U.S., other industrialized countries are facing similar challenges with personal behavior patterns, adverse health impacts, and health disparities. Thus the topics discussed in this series have implications well beyond the U.S. In this 4th Special Issue we address (a) the potential health impacts of liberalizing laws on recreational marijuana use; (b) the ongoing challenge of tobacco use in vulnerable populations; and (b) the importance of weight management and physical activity in caring for vulnerable medical populations. Across each of these topics we include contributions from accomplished policymakers and scientists to acquaint readers with recent accomplishments and remaining knowledge gaps and challenges in these important topic areas.