The prevalence of the neuropathological lesions of Alzheimer's disease is independent of race and gender

Senile plaques (SP) and neurofibrillary tangles (NFT) are the lesions chara cteristic of Alzheimer's disease (AD). In this study, we examined variation in the proportion of individuals who had these lesions by race, age, and g ender in a series of 138 autopsies conducted at the Office of the Chief Med ical Examiner of the State of Maryland between 1990 and 1998. Cases were se lected on the bases of age between 40 to 79 years and non-natural manner of death, and included 73% males, 61% subjects < 65 years of age, and 42% Afr ican Americans. Observations were conducted on histologic sections of the h ippocampus, entorhinal cortex, and inferior temporal cortex stained with si lver (Hirano method) and immunostained for AP-amyloid. We found that SP and NFT are strongly associated with age. These lesions begin to appear in the early to late 40s, depending on the anatomic location, and become common i n the 6th decade, preceding by one to two decades the age at which AD becom es clinically prevalent. No difference in the prevalence of SP or NFT was f ound by gender or between whites and African Americans. The latter is in co ntrast to epidemiologic studies that suggest AD is more prevalent in Africa n Americans than in whites. (C) 2001 Elsevier Science Inc. All rights reser ved.