Differential association between physical activity behaviours and dynapenia by comorbid diseases in community-dwelling Korean older adults.

Background: Physical activity (PA) behaviours and comorbid diseases are associated with muscle strength. However, the association between dynapenia and detailed PA behaviours, including participation in aerobic and resistance exercises and sedentary behaviour (SB), in relation to comorbid diseases has not yet been investigated. Using nationwide data, this study aimed to evaluate the independent association of dynapenia with detailed PA behaviour (participation in aerobic and resistance exercises and SB), and assess the differential associations of detailed PA behaviour with dynapenia according to comorbid diseases with prevalent sarcopenia.

Methods: A total of 7,558 community-dwelling older adults aged ≥ 65 years who were included in the Korea National Health and Nutrition Examination Survey from 2014 to 2019 were included in the present study. Cross-sectional associations between PA behaviours (participation in aerobic exercise, participation in resistance exercise, and SB) and dynapenia were analysed using complex-sample multivariable-adjusted logistic regression models according to the type of comorbid disease (cardiovascular disease [CVD], diabetes mellitus [DM], and chronic lung disease [CLD]).

Results: Sufficient aerobic exercise, sufficient resistance exercise, and low sedentary time of < 420 min/day showed independent negative associations with dynapenia (odds ratio [OR], 0.71; 95% confidence interval [CI], 0.60-0.83; OR, 0.54; 95% CI, 0.42-0.69; and OR, 0.84; 95% CI, 0.72-0.97, respectively). Among the participants with CVD or CLD, the associations of sufficient resistance exercise (OR, 0.46; 95% CI, 0.26-0.82 and OR, 0.51; 95% CI, 0.35-0.75 for CVD and CLD, respectively) and low sedentary time (OR, 0.66; 95% CI, 0.45-0.98 and OR, 0.71; 95% CI, 0.55-0.93 for CVD and CLD, respectively) with dynapenia were significant, whereas the association of sufficient aerobic exercise with dynapenia was insignificant. Meanwhile, in participants with DM, sufficient aerobic exercise (OR, 0.70; 95% CI, 0.52-0.94) and sufficient resistance exercise (OR, 0.45; 95% CI, 0.29-0.70) were independently associated with dynapenia, whereas no association between SB and dynapenia was found.

Conclusion: We observed an independent inverse association between PA behaviours and dynapenia. Disease-specific associations between each PA behaviour (sufficient aerobic exercise, sufficient resistance exercise, and low sedentary time) and dynapenia differed in the older adults. Therefore, these differences should be acknowledged during interventions for this population.