Baseline Characteristics and Their Associations with Body Composition of Active-Duty Service Members Enrolling in a Randomized Controlled Trial of a Weight Management Program.

Introduction: Increasing rates of overweight and obesity among military service members (SMs) necessitate the implementation of weight management interventions. Evidence for the effectiveness of military weight management interventions is mixed. Effectiveness may be impacted by individual sociodemographic, psychiatric, psychological, and behavioral factors. Baseline data from SMs who were overweight/obese or at risk of failing body composition or physical fitness tests and enrolling in a weight management randomized controlled trial were used to examine (1) individual characteristics of this sample as a whole and by gender and (2) relationships between those characteristics and body composition metrics that are targeted by military weight management interventions. Understanding these relationships may inform intervention approaches.

Materials And Methods: Active duty SMs (N = 178) who enrolled in a randomized clinical trial of the Navy's weight management program "ShipShape" at a large military hospital provided data at their baseline visit. Because of gender differences in average body fat percentage (BF%) and underrepresentation of women SMs in research, independent samples t-tests and chi-square analyses were used to examine differences between male and female SMs across study variables. Multiple regression analyses were used to examine relationships of sociodemographic, psychiatric, psychological, and behavioral variables with body composition metrics, including weight, body mass index (BMI), BF%, and waist circumference (WC).

Results: Participants (61% female; Mage = 29.66 ± 6.92 years; 59.60% White) had an average BMI in the "obese" range (MBMI = 33.1 ± 3.9 kg/m2). Female participants had significantly higher BF% and significantly lower weight and WC than male participants. Compared to male participants, females reported significantly higher rates of pain and headache diagnoses, lifetime diagnosis of an anxiety disorder, lifetime treatment for a mental health concern, lifetime experiences of sexual trauma/harassment and military sexual trauma, and higher current anxiety and post-traumatic stress disorder symptoms. Across all SMs, body composition metrics were significantly associated with several demographic variables, including gender, age, marital status, Asian race, and Black race. Higher weight-related stigma was significantly associated with higher weight, BMI, BF%, and WC. Additionally, more emotional eating was significantly associated with higher BF%, and higher weight-loss confidence was significantly associated with higher BMI. Sociodemographic, psychiatric, psychological, and behavioral variables predicted the greatest variance in BF% compared to other body composition metrics evaluated.

Conclusions: Participants in this study were more likely to be female, relatively young members of the Navy with overweight/obesity, who endorsed pain-related medical conditions, probable mental health conditions, and traumatic experiences at relatively high rates. Despite high endorsement of anxiety, depression, and post-traumatic stress disorder symptoms in this group, only weight-related stigma consistently emerged as significantly associated with body composition metrics. Regression results varied by body composition metric, with the most variance explained in BF%, suggesting that BF% may relate most strongly to sociodemographic, psychiatric, psychological, and behavioral variables associated with weight management. These results highlight the need for weight management programs that address weight-related stigma and mental health concerns of SMs to maximize the effectiveness of intervention efforts.