Lifestyle, genetic risk, plasma pTau217, and incident cognitive impairment in WRAP

Whether lifestyle-based dementia risk in midlife impacts risk of incident cognitive impairment (ICI) in the presence of apolipoprotein E (APOE) ε4 allele or plasma pTau217 remains unknown.

In initially cognitively unimpaired participants (N = 1088; baseline age, M(SD) = 57.8(6.5) years) from the Wisconsin Registry for Alzheimer's Prevention (WRAP), we investigated the relationship between lifestyle-based dementia risk (e.g., low, moderate, and high lifestyle-based risk tertiles) and risk of ICI when accounting for APOEε4 or plasma pTau217-ALZpath using Cox regressions (median follow-up years = 8.2(interquartile range [IQR]: 5.5-10.8)).

Less healthy lifestyle tertiles were associated with higher risk of ICI compared to the healthiest tertile across APOEε4 carriers and non-carriers (moderate, hazard ratio [HR] = 1.58, 95% confidence interval; [CI] 1.17-2.15, p = 0.003; high, HR = 2.08, 95% CI 1.56-2.76, p < 0.001) and across all pTau217 levels (moderate, HR = 1.63, 95% CI 1.20-2.21, p = 0.002; high, HR = 2.19, 95% CI 1.64-2.91, p < 0.001).

In WRAP, healthier lifestyle in midlife was associated with lower risk of ICI, regardless of APOEε4 carriage or pTau217 level.

Healthier lifestyle is associated with reduced risk of incident impairment. Apolipoprotein E (APOE) ε4 allele carriage and pTau217 are associated with higher risk of incident impairment. No significant lifestyle risk by APOEε4 nor pTau217 interactions were observed. Combined lifestyle tertiles and APOEε4 carriage increased risk monotonically. Lifestyle tertiles increased impairment risk monotonically across pTau217 groups.