Sex differences in Alzheimer's disease and common neuropathologies of aging

Abstract

Alzheimer's dementia is significantly more common in women than in men. However, few pathological studies have addressed sex difference in Alzheimer's disease (AD) and other brain pathologies. We leveraged postmortem data from 1453 persons who participated in one of two longitudinal community-based studies of older adults, the Religious Orders Study and the Rush Memory and Aging Project. Postmortem examination identified AD pathologies, neocortical Lewy bodies, DNA-binding protein 43 (TDP-43), hippocampal sclerosis, gross and micro infarcts, atherosclerosis, arteriolosclerosis, and cerebral amyloid angiopathy. Linear and logistic regressions examined the association of sex with each of the pathologic measures. Two-thirds of subjects were women (n = 971; 67%), with a mean age at death of 89.8 (SD = 6.6) years in women and 87.3 (SD = 6.6) in men. Adjusted for age and education, women had higher levels on a global measure of AD pathology (estimate = 0.102, SE = 0.022, p < 0.001), and tau tangle density in particular (estimate = 0.334, SE = 0.074, p < 0.001), and there was a borderline difference between women and men in amyloid-β load (estimate = 0.124, SE = 0.065, p = 0.056). In addition, compared to men, women were more likely to have more severe arteriolosclerosis (OR = 1.28, 95% CI:1.04-1.58, p = 0.018), and less likely to have gross infarcts (OR = 0.78, 95% CI:0.61-0.98, p = 0.037), although the association with gross infarct was attenuated after controlling for vascular risk factors. These data help elucidate the neuropathologic footprint of sex difference in AD and other common brain pathologies of aging.

Keywords: Alzheimer disease; Amyloid; Arteriolosclerosis; Pathology; Sex; Tau proteins.

Figure 1.

Levels of AD pathological indices among women and men, controlled for age at death and education. Levels of the amyloid and tangles pathologies were measured by using immunohistochemistry with the monocloncal antibodies against phosphorylated tau (AT8, Innogenetics, Alpharetta GA, 1:1000) and amyloid-β (MO0972 DAKO, 1:100). The global AD pathology is a composite measure derived from the 3 AD pathologic counts in the Bielschowsky silver stain sections: neuritic plaques, diffuse plaques, and neurofibrillary tangles.