Low Muscle Mass and Depressed Mood in Korean Adolescents: a Cross-Sectional Analysis of the Fourth and Fifth Korea National Health and Nutrition Examination Surveys

BACKGROUND: Muscle mass and muscle function are related to depressed mood in studies of adults. Like adults, Korean students are highly likely to suffer from decreased muscle mass due to social conditions. In this study, we evaluated the muscle mass status of Korean adolescents and assess the effect of muscle on depressive mood. METHODS: A total of 1,233 adolescent boys and girls participants from the Korea National Health and Nutrition Examination Survey were enrolled in our study. Participants underwent dual-energy X-ray absorptiometry for assessment of appendicular muscle mass and completed questionnaires regarding depressed mood, stress, suicidal ideations, and attempts. RESULTS: There was no difference in depressive mood according to muscle mass among boys (P = 0.634); girls with decreased muscle mass had a greater tendency for depressed mood compared to girls with optimal muscle mass (P = 0.023). After adjusting for age, waist circumference-to-height ratio, smoking status, alcohol consumption, frequency of physical activity, self-reported obesity, weight-loss efforts, and monthly household income, girls with low muscle mass (LMM) were 2.60 times more at risk of developing depression than girls with normal muscle mass (95% confidence interval [CI], 1.05–6.49; P = 0.040). This trend was similar for girls with LMM with obesity (95% CI, 1.00–11.97; P = 0.049). CONCLUSION: Adolescent girls who have insufficient muscle mass are more likely to report depressed mood than girls who have ideal muscle mass. Interventions for maintaining proper muscle mass are required.