Journal of Traumatic Stress xxxx 2017, 00, 1–10 Patterns of Smoking and Unhealthy Alcohol Use Following Sexual Trauma Among U.S. Service Members Amber D. Seelig, 1 Anna C. Rivera, 2 Teresa M. Powell, 2 Emily C. Williams, 3,4 Arthur V. Peterson, 5,6 Alyson J. Littman, 1,3,7 Charles Maynard, 1,3,4 Amy E. Street, 8,9 Jonathan B. Bricker, 5,10 and Edward J. Boyko 1,7 1 Seattle Epidemiologic Research and Information Center, Department of Veterans Affairs Puget Sound Health Care System, Seattle, Washington, USA 2 Henry M. Jackson Foundation for the Advancement of Military Medicine, Bethesda, Maryland, USA 3 Denver-Seattle Center of Innovation for Veteran-Centered and Value-Driven Care, Health Services Research and Development, VA Puget Sound Health Care System, Seattle, Washington, USA 4 Department of Health Services, University of Washington, Seattle, Washington, USA 5 Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, Washington, USA 6 Department of Biostatistics, University of Washington, Seattle, Washington, USA 7 Department of Epidemiology, University of Washington School of Public Health, Seattle, Washington, USA 8 National Center for PTSD, VA Boston Healthcare System, Boston, Massachusetts, USA 9 Department of Psychiatry, Boston University School of Medicine, Boston, Massachusetts, USA 10 Department of Psychology, University of Washington, Seattle, Washington, USA In the first known longitudinal study of the topic, we examined whether experiencing sexual assault or sexual harassment while in the military was associated with increased risk for subsequent unhealthy alcohol use and smoking among U.S. service members in the Millennium Cohort Study (2001–2012). Adjusted complementary log–log models were fit to estimate the relative risk of (a) smoking relapse among former smokers (men: n = 4,610; women: n = 1,453); (b) initiation of unhealthy alcohol use (problem drinking and/or drinking over recommended limits) among those with no known history of unhealthy alcohol use (men: n = 8,459; women: n = 4,816); and (c) relapse among those previously reporting unhealthy alcohol use (men: n = 3,487; women: n = 1,318). Men who reported experiencing sexual assault while in the military had sixfold higher risk for smoking relapse: relative risk (RR) = 6.62; 95% confidence interval (CI) [2.34, 18.73], than men who did not. Women who reported experiencing sexual assault while in the military had almost twice the risk for alcohol relapse: RR = 1.73; 95% CI [1.06, 2.83]. There were no other significant associations. These findings suggest that men and women may respond differently following sexual trauma, and support future concerted policy efforts by military leadership to prevent, detect, and intervene on sexual assault. A portion of this work was presented at the 2015 Society for Epidemiologic Research Annual Meeting in Denver, Colorado (June 16–19, 2015). This work was supported in part by Merit Award (ZDA1-04-W10) from the U.S. Department of Veterans Affairs Clinical Science Research and Devel- opment Service. Dr. Littman was supported by a Rehabilitation Research & Development Career Development Award (#6892). Dr. Williams was supported by a Career Development Award from Veterans Affairs (VA) Health Services Research & Development (CDA 12–276). The Millennium Cohort Study is funded through the Military Operational Medicine Research Program of the U.S. Army Medical Research and Ma- teriel Command, Fort Detrick, Maryland, and the Navy Bureau of Medicine and Surgery, under Work Unit No. 60002. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, Department of the Army, Department of Defense, De- partment of Veterans Affairs, or the U.S. Government: U.S. Government Work (17 U.S.C. §105). This work has been approved for public release; distribution unlimited. Human subjects participated in this study after giving their free and informed consent. This research has been conducted in compliance with all Sexual harassment and sexual assault occurring during mil- itary service, sometimes referred to as military sexual trauma (MST) has emerged over the past several years as an important issue (Fu & Sbrocco, 2015; Risen, 2013). A recent publication estimated that 20,300 sexual assaults occurred in the last year among active-duty service men and women (1% of men, 5% of women) and that 90% of these assaults took place within a military setting or were perpetrated by a service member applicable federal regulations governing the protection of human subjects in research (Protocol NHRC.2000.0007). Correspondence concerning this article should be addressed to Amber Seelig, VA Puget Sound Health Care System, 1660 S. Columbian Way, S-152E, Seattle, WA 98108. E-mail: amber.seelig@va.gov Published 2017. This article is a U.S. Government work and is in the public domain in the USA. View this article online at wileyonlinelibrary.com DOI: 10.1002/jts.22214 1