摘要:Objectives. We examined whether military service, including deployment and combat experience, were related to smoking initiation and relapse. Methods. We included older (panel 1) and younger (panel 2) participants in the Millennium Cohort Study. Never smokers were followed for 3 to 6 years for smoking initiation, and former smokers were followed for relapse. Complementary log-log regression models estimated the relative risk (RR) of initiation and relapse by military exposure while adjusting for demographic, health, and lifestyle factors. Results. Deployment with combat experience predicted higher initiation rate (panel 1: RR = 1.44; 95% confidence interval [CI] = 1.28, 1.62; panel 2: RR = 1.26; 95% CI = 1.04, 1.54) and relapse rate (panel 1 only: RR = 1.48; 95% CI = 1.36, 1.62). Depending on the panel, previous mental health disorders, life stressors, and other military and nonmilitary characteristics independently predicted initiation and relapse. Conclusions. Deployment with combat experience and previous mental disorder may identify military service members in need of intervention to prevent smoking initiation and relapse. Reducing tobacco use disparities is a high public health priority. 1 The available evidence has shown that US military service members use tobacco more than the general population. The prevalence of smoking within the past 30 days among members of the US military in 2011 was estimated at 24.5%, exceeding the US adult population prevalence of 19.0%, as estimated from the National Health Interview Survey. 2,3 These disparities result in serious consequences for US military personnel. Tobacco use accounts for at least 16% of all deaths among current and former US military personnel and 10% of hospital bed days in US Department of Defense health care facilities. 4 In addition, tobacco use is associated with poorer job productivity. Specifically, 14.1% of lost workdays among military men and 3.0% among women can be attributed to smoking. 5 Tobacco use by servicemembers may also set the stage for a lifetime of use that results in substantial morbidity and lost productivity and millions of years of potential life lost. 6 One approach to reducing tobacco use disparities among military personnel is to identify higher risk groups for more intensive smoking prevention programs. Although the higher prevalence might be explained by selection factors leading to more smokers entering the military, one investigation found that the prevalence of smoking and use of smokeless tobacco among military personnel on active duty was twice that of new male military recruits, leading the authors to conclude that the military environment in some way promotes tobacco use. 7 Reasons for a higher smoking prevalence in the military may include boredom, a desire to maintain weight within standards, a military culture that promotes tobacco use, peer influences, coping strategy for mental health symptoms, deployment experiences, and stress reduction. 8–14 Longitudinal research on predictors of smoking initiation and relapse in military populations is sparse. Using data from the Millennium Cohort Study, we previously reported a higher risk of smoking initiation associated with deployment with combat exposure and relapse associated with any deployment. 15 The initial participants who had never smoked were generally older than the usual age at smoking initiation and had considerable military experience, with 36% having been deployed to conflicts before the initiation of operations in Afghanistan and Iraq. Although most smokers have initiated smoking by age 18 years, an increasing proportion are initiating smoking between ages 18 and 29 years. 16,17 The Millennium Cohort Study has subsequently recruited younger participants with little military experience (≤ 2 years) and can better address both smoking initiation in the age ranges in which adoption of this habit is more common and military exposures assessed longitudinally after enrollment into the study. We assessed risk factors associated with smoking initiation and relapse in both younger and older participants in the Millennium Cohort Study by examining military, mental health, and other characteristics associated with these outcomes.