Gender-Specific Relationships of Lifestyle and Physical Activity with Body Composition Among Medical Students

Background/Objectives: During their university education, medical students may develop unhealthy lifestyle behaviors during university education, including reduced physical activity, increased sedentary behavior, and inadequate dietary habits, which may affect their body composition. This study aimed to identify demographic, lifestyle, and physical activity predictors of body composition among medical students. Methods: This cross-sectional study included 176 undergraduate medical students from the Faculty of Medicine, University of Belgrade. Demographic characteristics, lifestyle habits, and physical activity were assessed using the questionnaire. Body composition was measured using the InBody 370S multifrequency bioelectrical impedance analyzer. Student’s t-test and chi-square test were used to assess between group differences. Univariate and multivariate linear regression analyses were performed separately for males and females. Results: Most students had normal BMI (76.1%), while 15.3% were overweight and 2.8% obese. Men had higher mean BMI (24.2 ± 3.4 vs. 21.5 ± 2.5 kg/m2) and lower body fat percentage (16.6 ± 5.3% vs. 27.0 ± 6.3%) than women (p < 0.001). In males, sport participation was associated with total body water (p = 0.008) and fat-free mass (p = 0.016), while vigorous physical activity predicted protein mass (p = 0.002). In females, sport participation was associated with total body water (p = 0.029), fat-free mass (p = 0.030), protein (p = 0.020), and skeletal muscle mass (p = 0.021). Conclusions: Sport participation was related to both higher total body water and fat-free mass in both males and females, and, was additionally related to higher protein and skeletal muscle mass in females.