Associations of changes in the dynapenia and cognitive function in middle-aged and older adults.

OBJECTIVES

Dynapenia is the age-related loss of muscle strength. Decreased muscle strength, including handgrip strength, is associated with cognitive impairment in older adults, possibly due to weakening of the neuromuscular system. However, changes in muscle strength and cognitive function may occur simultaneously and reflect aging. We aimed to investigate the relationship between repeated measures of muscle strength and changes in cognitive function and new-onset mild cognitive impairment (MCI) in middle-aged and older adults.

STUDY

DESIGN

A prospective cohort study.

METHODS

This study used data from the Korean Longitudinal Study of Aging, which was conducted from 2006 to 2020. The participants included 10,516 adults aged ≥45 years. Muscle strength was measured using handgrip strength and was divided into quartiles according to sex. Dynapenia was defined as handgrip strength <28 kg in men and <18 kg in women. MCI was defined as a Korean Mini-Mental State Examination score <24.

RESULTS

In our repeated-measures longitudinal analysis, the odds ratios (OR) for MCI were 1.84 (95 % confidence intervals [CI]: 1.71-1.97) for dynapenia; 2.07 (95 % CI: 1.85-2.31), the lowest absolute handgrip strength; and 2.17 (95 % CI: 1.95-2.42), the lowest relative handgrip strength. After a 14-year follow-up, the hazard ratio for MCI was 1.29 (95 % CI: 1.15-1.46) in the newly diagnosed dynapenia group and 1.29 (95 % CI: 1.14-1.47) in the persistent dynapenia group.

CONCLUSIONS

Dynapenia and low muscle strength were associated with an increased risk of MCI over time. Furthermore, persistent and newly diagnosed dynapenia were associated with an increased risk of new-onset MCI in middle-aged and older Korean adults.