Cognitive performance and mortality in people over 50 in Mexico

Objective. Determine the correlation between the low cognitive performance recorded in 2001 in the National Study on Health and Aging in Mexico (ENASEM) and the mortality reported in 2003 during the second phase of that same study. Methods. The subjects selected were people aged 50 or over who had completed the sections in the 2001 survey pertaining to cognitive exercises, health status, and functionality and assistance with daily activities. Cognitive performance was assessed in 2001 using an abridged version of the Cross-Cultural Cognitive Examination (scale: 0 to 80 points). In 2003, there was a follow-up to the interviewees, in which their survival or death was recorded. Results. The groups of interviewees scoring less than 40 had a cumulative survival rate of 96.1%, with a mean of 26.49 months of survival (CI 95% 26.41-26.57), while those scoring 40 points or over had a cumulative survival rate of 98.7%, with a mean of 28.76 months (CI 95% 28.68-28.85) (Log Rank X² = 59,230 P > 0,001). A score of less than 40 in the cognitive assessment was associated with a relative risk of death of 1.863 (CI: 95% 1.30-2.65) in the multivariate analysis. Also associated with higher mortality was older age, self-reported diabetes, cancer, having smoked at some time, receiving assistance in at least one instrumental activity of daily living, and scoring higher on the depression scale. Conclusions. A score of less than 40 in the abridged version of the Cross-Cultural Cognitive Examination was independently correlated with an increase in mortality within the next two years.