In the at risk cohort, longer reproductive period was associated, predictably, with earlier menarche and (particularly) later menopause, and with a higher ICEEE (Table 2). Longer reproductive period was also associated with older age; with being more likely to complete primary education; with lower parity; with older age at birth of first child; with a lower prevalence of hazardous drinking and stroke; with taller stature, and with better baseline cognitive function (the composite CSI-D COGSCORE, and the CERAD animal naming test, but not the CERAD 10 word list delayed recall). The effect on COGSCORE (effect size per quarter of reproductive period +0.064, 95% CI +0.021 to +0.107, r2 = 0.1%) was no longer statistically significant having adjusted for age, education, marital status, stroke, hazardous alcohol use, and height (+0.024, 95% CI -0.019 to +0.067, r2 = 0.0%). The effect on animal naming (+0.195, 95% CI +0.094 to +0.295, r2 = 0.2%) also lost statistical significance after adjusting for the same covariates (+0.092, 95% CI -0.006 to +0.190, r2 = 0.0%). Although the proportion with one or more APOE e4 alleles did decline significantly across quarters of reproductive period (p = 0.048, Table 2), neither mean reproductive period (p = 0.08), nor mean age at menarche (p = 0.38), nor mean age at menopause (p = 0.17) differed significantly across APOE genotypes.