Association of cognitive impairment and grip strength trajectories with mortality among middle-aged and elderly adults

Background: This study investigates whether maintaining high levels of cognitive impairment and weak grip strength will predict a higher risk for mortality. Methods: Data from the Korean Longitudinal Study of Aging (KLoSA) from 2006 to 2014 was assessed using longitudinal data analysis and included 5,812 research subjects. Our modeling approach jointly estimated multi-period trajectories of grip strength and cognitive impairment, and the primary analysis was based on Cox proportional hazards models. Results: A four-class linear solution fit the data best in both cognitive impairment and grip strength based on the model fitness, respectively. The hazard ratio (HR) of mortality in group 1 (consistently low) of cognitive impairment and of grip strength were 2.114 times higher (p-value 0.001) and 3.405 times higher (p-value <.0001) compared with group 3 (consistently high) and group 4 (consistently high), respectively. Conclusion: This study provides insightful scientific evidence into the specificity of longitudinal changes in grip strength and cognitive impairment on mortality. Our findings suggest that declined cognitive ability and weak grip strength are predictors of mortality in older Korean people.