Gender-Specific Differences in Cognitive Changes, Frailty and Mortality in Elderly

Arnold B. Mitnitski, Dalhousie University
Nader Fallah, Dalhousie University
Kenneth Rockwood, Dalhousie University

We analyzed how the changes in cognition are related to general health status, in elderly men and women using the longitudinal component of the Canadian Study of Health and Aging (n = 8403). General health status was defined by the Frailty Index combining 40 health related deficits including symptoms, signs, illnesses, and disabilities. Cognitive states were defined as the errors in the modified Mini-Mental State Examination. Both cognitive improvement and declines were modeled using a four-parameter Markov chain with truncated Poisson distribution. The model parameters were dependent on age, education and frailty. We demonstrated that both age and frailty were independently associated with cognitive changes and risks of death while higher education is beneficial to cognition but did not improve survival. Frail women and especially frail men showed significantly higher cognitive decline than non frail women and men. Frail men had also more chances to die comparing to frail women.