【Background】The longitudinal association of sarcopenia with risk of new-onset mild cognitive impairment (MCI) in a general population including middle and older adults remains unknown. The purpose of this study was to investigate the effects of sarcopenia on risk for new-onset MCI over 6 years using a large nationwide sample of cognitively healthy adults.
【Methods】 Study participants included 6,435 middle and older adults at baseline, using data from the Korean Longitudinal Study of Ageing. The sarcopenia was defined using handgrip strength as a muscle quality. Cognitive function was evaluated using the Mini-Mental Status Evaluation for each participant at baseline and during 6-years at each 2-year cycle.
【Results】 The hazard ratio (HR) for MCI significantly and linearly increased according to sarcopenia status independent of potential confounding factors (HR: 1.51, 95% CI: 1.26–1.81 for sarcopenia, HR: 1.30, 95% CI: 1.11–1.52 for normal-low vs. high group). Using stratified analyses, a significant association between sarcopenia status and risk of MCI was observed in those with low physical activity, but not those with high physical activity (P-interaction=0.055). Significant associations were also observed between sarcopenia status and increased risk of new-onset MCI in other stratified models, consistent with findings in the overall population.
【Conclusions】In conclusion, we found that sarcopenia was strongly associated with increased risk of new-onset MCI over 6 years of follow-up in cognitively healthy adults at baseline. Our findings suggest that maintaining skeletal muscle strength may be useful in preventing MCI. Furthermore, increased physical activity may offset the negative impacts of sarcopenia on risk of MCI.