Circadian rhythm disruption is associated with an increased risk of sarcopenia: a nationwide population-based study in Korea

Reduced sleep quality is associated with an increased risk of sarcopenia. However, the potential effects of disturbing the regular circadian rhythm, as occurs with shift work, on the risk of sarcopenia have not been established. Data from 9105 workers from the 2008–2011 Korean National Health and Nutrition Examination Survey were analyzed. Sarcopenia, measured by dual-energy X-ray absorptiometry, was defined as one standard deviation below the mean of the appendicular skeletal muscle/body mass index value of a young reference group. Compared to the group that had never experienced shift work, the odds ratio (OR) for sarcopenia with a 95% confidence interval (95% CI) for the shift work group was 1.7 (1.5–1.9); the association remained even after adjusting for confounding variables, including age, sex, total fat mass, insulin resistance profile, smoking, alcohol intake, diet, and physical activity. The results of the subgroup analysis indicated that the highest risk of sarcopenia was among workers engaging in shift work with an irregular schedule (OR 1.8, 95% CI 1.3–2.4). Disruption of circadian rhythm by shift work was associated with increased risk of sarcopenia. Intervention strategies are needed to prevent sarcopenia in shift workers.