A progress report on the prevalence of Alzheimer's lesions in a Bombay hospital population

Preliminary neuropathological findings are presented for a nonrandom subset of 100 older patients (ages 59–90 years) chosen from among a sample of 2000 autopsies performed at the Sir J. J. Group of Hospitals from October 1989 to April 1991. Gross examination included brain weights and estimates of cortical atrophy. Microscopic examination of sections from 13 regions of the brain included hematoxylin and eosin, BielsGross–chowsky silver stains and Congo red stains (examined by polarized light). For the aggregate sample, increasing degrees of cortical cerebral atrophy were observed with advancing age. A regression analysis of brain weight versus age revealed age-related declines in brain weights for males, but not for a smaller sample (n = 28) of female subjects. A few neurofibrillary tangles were found in 88% of cases and in all sites, surprisingly including frequent involvement of Purkinje cells of the cerebellum, an observation that will require confirmation with other methodologies. The most prevalent type of neuropathology involved cerebrovascular accidents, especially old infarcts. Only five cases exhibited numerous neurofibrillary tangles. Neuritic plaques were seen in six cases and amyloid was detected in seven cases. Of two cases with a clinical diagnosis of dementia, one 65-year-old male had multiple cerebral infarcts and a 60-year-old male had, in addition to multiple lacunar infarcts, moderate numbers of tangles and a few neuritic plaques (without amyloid cores) sufficient to warrant a diagnosis of 'probable Alzheimer's disease' by consortium to establish a registry of Alzheimer's disease (CERAD) criteria. The overall impression from this initial survey is that Alzheimer's disease does not appear to be particularly prevalent in our population. Given the biased nature of the sampling, however, and the limited numbers of subjects of advanced ages, no definitive conclusions as to prevalence can be made. This study, however, does indeed point out the potential for obtaining a substantial amount of relevant clinical and neuropathological data in a developing country.