Forty-five percent of Alzheimer's disease (AD) cases may be preventable. Validated tools for measuring environmental factors, with precision equal to that of current biological and genetic assessment tools, are currently lacking.
We used the dynamic Neurocognitive Adaptation (dNA) scale, our validated tool to explore protective factors in AD, in 410 older adult participants (50% women). The dNA asks participants to recall cognitive, creative, physical, and social activities that they engaged in at seven different time periods in their lives. We examined associations among engagement in these domains using distance correlations and tested differences in domain engagement over time with repeated-measures analysis of variance. We calculated within-subjects comparisons for time and all interactions among time, sex, and education. We examined between-subjects factors for sex, education, and their interaction. From these models, we constructed visualizations of estimated marginal means against time to assess potential patterns of interest.
Physical and creative domain engagements were significantly correlated (p < 0.001) in the full sample, and social engagement correlated with physical (p < 0.001) and creative (p = 0.047) domains among females. Cognitive engagement increased over time (p < 0.001) for the full sample, while physical and creative engagement increased from childhood to adolescence, then decreased over time (p < 0.001). In contrast, social engagement increased from childhood to adolescence, declined through the senior years, and then sharply increased in old age. Overall, women showed higher cognitive engagement (p = 0.024) and men showed higher physical engagement (p = 0.011). Education was positively related to higher scores in all domains.
Our scale provides new insight into the correlation of environmental factors with education, suggests areas for lifestyle intervention, and highlights the importance of sex differences and middle age as a potential transition stage.