Association between grip strength and cognitive function in older adults: results from a cross-sectional study and Mendelian randomization analyses.

BACKGROUND

Impaired cognitive function is a known marker of human aging, and the causal relationship between grip strength, as a part of physical activity, and cognitive function is still unclear.

METHOD

Data on grip strength and cognitive function were collected in a cross-sectional study conducted in Guangxi Gongcheng 2018-2019. Generalized linear regression models were utilized to assess the relationship between grip strength and cognitive impairment. A two-way two-sample MR study was used to further determine the causal relationship, mainly using Inverse variance weighted (IVW), weighted median, and MR-Egger. Sensitivity analysis was also used to confirm the robustness of the results. Finally, MVMR analysed BMI and CRP as potential confounders.

RESULT

A total of 1723 participants were included in the cross-sectional study. Generalized linear regression models showed that low grip strength was a risk factor for cognitive impairment after adjusting for covariates such as age, gender, and ethnicity (OR: 0.965; 95 % CI: 0.947 to 0.984), and the onset of cognitive impairment led to reduced grip strength (OR: 0.251; 95 % CI: 0.113 to 0.559). The results of the two-way two-sample MR also supported the mutual causal relationship between low grip strength (OR = 0.93; 95 % Cl: 0.89-0.97) and cognitive impairment (OR = 0.878; 95 % Cl: 0.794-0.971). The results of the MVMR analysis also proved this relationship.

CONCLUSION

Low grip strength increases the risk of cognitive impairment, and conversely, cognitive impairment contributes to an increased risk of reduced grip strength.