Including the present BLSA sample, we identified five samples with data on neuroticism (total N = 5054; incident AD, N = 607) and three samples with data for each of the other four factors (N = 3342; incident AD, N = 382). We did not conduct meta-analyses for the facets because we found only one study that examined the facets of neuroticism aside from the current BLSA sample. Table 3 presents the characteristics of the studies included in the meta-analyses. All traits were measured with some variation of the NEO-PI-R instrument, and all studies included at least age, sex, and education as covariates. The HRs from each study and the pooled association are presented in Table 4. The meta-analysis confirmed a highly significant effect for neuroticism (p = 2*10−9): for every SD increase in this trait, the risk of AD increased by more than 30% (HR = 1.33; 95%CI =1.21–1.45). The association was highly consistent across studies (Q = 2.6; degrees of freedom (df) = 4; p = 0.63), and in this set of studies we observed no statistical evidence
