Prevalence, Adverse Events, and Factors Associated with Dietary Supplement and Nutritional Supplement Use by US Navy and Marine Corps Personnel

Joseph J. Knapik, Daniel W. Trone, Krista G. Austin, Ryan A. Steelman, Emily K. Farina, Harris R. Lieberman

About 50% of Americans and 60% to 70% of US military personnel use dietary supplements, some of which have been associated with adverse events (AEs). Nutritional supplements like sport drinks and sport bars/gels are also commonly used by athletes and service members. Previous dietary supplement and nutritional supplement surveys were conducted on Army, Air Force, and Coast Guard personnel. The aim of this cross-sectional study was to investigate dietary and nutritional supplement use in Navy and Marine Corps personnel, including the prevalence, types, factors associated with use, and AEs. A random sample of 10,000 Navy and Marine Corps personnel were contacted. Service members were asked to complete a detailed questionnaire describing their personal characteristics, supplement use, and AEs experienced. In total, 1,708 service members completed the questionnaire during August through December 2014, with 1,683 used for analysis. Overall, 73% reported using dietary supplements one or more times per week. The most commonly used dietary supplements (used one or more times per week) were multivitamins/multiminerals (48%), protein/amino acids (34%), combination products (33%), and individual vitamins and minerals (29%). About 31% of service members reported using five or more dietary supplements. Sport drinks and sport bars/gels were used by 45% and 23% of service members, respectively. Monthly expenditures on dietary supplements averaged $39; 31% of service members spent ≥$50/mo. Multivariate logistic regression modeling indicated that female sex (women/men; odds ratio [OR]=1.76, 95% CI 1.32 to 2.36), higher educational level (college degree/no college degree; OR=2.23, 95% CI 1.62 to 3.30), higher body mass index (calculated as kg/m(2)) (≥30/<25; OR=1.67, 95% CI 1.06 to 2.63), and a greater amount of resistance training (≥271/0 to 45 min/week; OR=2.85, 95% CI 1.94 to 4.17) were associated with dietary supplement use. Twenty-two percent of dietary supplement users and 6% of nutritional supplement users reported one or more AEs. For combination products alone, 29% of users reported one or more AEs. The prevalence of dietary supplement use in Navy and Marine Corps personnel was considerably higher than reported in civilian investigations for almost all types of dietary supplements, although similar to most other military services. Factors associated with dietary supplement use were similar to those reported in previous military and civilian investigations. Prevalence of self-reported AEs was very high, especially for combination products.