“Predictors of ageing-related decline across multiple cognitive functions,” published in the most recent issue of the journal Intelligence, reports that only two factors seem to be important predictors of cognitive decline. Possession of the APOE e4 allele and level of physical fitness. From the paper:
participants with better general cognitive function at age 70 were younger when tested, had higher childhood intelligence, were more educated, were from more professional occupational classes, lived in more affluent areas, were fitter (on all three performance indicators), had lower BMI, were less likely to smoke, and were less likely to have cardio-metabolic illness. The four cognitive domains showed a similar pattern of results, with the additional finding that carriers of the APOE e4 allele also performed less well on the visuospatial and speed domains.
The paper also found that:
that women had significantly less general cognitive decline than men, mainly centered on Crystallized ability.
Here is the abstract:
It is critical to discover why some people’s cognitive abilities age better than others’. We applied multivariate growth curve models to data from a narrow-age cohort measured on a multi-domain IQ measure at age 11 years and a comprehensive battery of thirteen measures of visuospatial, memory, crystallized, and processing speed abilities at ages 70, 73, and 76 years (n = 1091 at age 70). We found that 48% of the variance in change in performance on the thirteen cognitive measures was shared across all measures, an additional 26% was specific to the four ability domains, and 26% was test-specific. We tested the association of a wide variety of sociodemographic, fitness, health, and genetic variables with each of these cognitive change factors. Models that simultaneously included all covariates accounted for appreciable proportions of variance in the cognitive change factors (e.g. approximately one third of the variance in general cognitive change). However, beyond physical fitness and possession of the APOE e4 allele, very few predictors were incrementally associated with cognitive change at statistically significant levels. The results highlight a small number of factors that predict differences in cognitive ageing, and underscore that correlates of cognitive level are not necessarily predictors of decline. Even larger samples will likely be required to identify additional variables with more modest associations with normal-range heterogeneity in aging-related cognitive declines.