Sex hormones and neuropathology in elderly men: the HAAS.

Experimental studies suggest 17-beta estradiol (E2) and testosterone (T) may have neuroprotective properties that are associated with Alzheimer's and vascular pathology. However, there are limited studies correlating steroid hormones with autopsy findings in humans. In this community-based autopsy study of elderly men (n=232) participating in the Honolulu Asia Aging Study, we found a significant decrease of neurofibrillary tangles in the highest tertile of free serum estradiol [IRR=0.43 (0.3-0.7)] after controlling for age at blood draw, interval from blood draw until death, ApoE allele, and socio-demographic health factors. Higher Free-T levels were associated with a two-fold increased risk for micro infarcts [IRR=2.2; 95% CI (1.2-4.1)]. There was no association between sex hormones and amyloid plaques or cerebral amyloid angiopathy. This community-based autopsy study suggests that peripheral levels of sex hormones are associated with neurofibrillary tangles and micro-infarcts, but not with other neuropathologic markers of brain disease in elderly men.