Neuropathological Analysis of Dementia in a Japanese Leprosarium

Abstract

In a neuropathological study of consecutive autopsies, prevalence and cause of dementia in a Japanese leprosarium were investigated, where more than 95% of inpatients with a mean age of 70 years are now free from active leprosy. In 10 years (1983–1992), clinically overt dementia at death was 35/136 (25.7%) in the age group over 65 years (mean age 79.4). Autopsy was performed in 85 cases (mean age 81 years), and clinically overt dementia was seen in 25 subjects (29.4%). Neuropathologically, Alzheimer''s disease (AD) was seen in 9 cases (10.6%), vascular dementia (VD) in 9 cases (10.6%), mixed type in 3 cases (3.5%) and unclassified in 4 cases (4.7%). In the age group of 65-84 years, AD was 5/58 (8.6%), VD was 4/58 (6.9%), mixed type was 2/58 (3.4%), and unclassified was 1/58 (1.7%). Compared with previous Japanese general population-based data, where VD was more frequent than AD, the rate of dementia in our leprosarium was high, and pathologically confirmed AD was as common as VD. Recently, a prophylactic effect of the antileprosy and anti-inflammatory drug DDS (dapsone, 4,4´-diaminodiphenyl sulfone) has been suggested. Lepromatous patients take more DDS (51.9%) than tuberculoid patients (11.5%), however, as the dementia rate of tuberculoid leprosy (17.9%) in those 65–84 years old is similar to lepromatous leprosy (15.9%) in our study, we do not support their viewpoint.

A pleiotropic effect of theAPOEgene: association ofAPOEpolymorphisms with multibacillary leprosy in Han Chinese from Southwest China

“…Previous epidemiological studies have shown that elderly people with leprosy treated by antileprosy drugs had a significantly lower incidence of dementia compared with drug‐free patients, although there is some controversy . Namba et al .…”

The prevalence of dementia and depression in Taiwanese institutionalized leprosy patients, and the effectiveness evaluation of reminiscence therapy—a longitudinal, single‐blind, randomized control study

“…The literature regarding dementia in leprosy patients is limited, and the results are controversial. Compared with the general population, an epidemiology study revealed that the population of leprosy patients had a significantly low prevalence rate of senile dementia, from 2.9% to 6.25% (McGeer et al , ), but other studies have indicated that leprosy patients in leprosariums have a higher‐than‐normal rate of senile dementia, at 16.8–20.7% (Goto et al , ; Endoh et al , ). The differing results might have been due to the bias arising from the sampling of different research settings.…”

Recovery of Dementia Syndrome following Treatment of Brain Inflammation

“…According to conflicting reports by the Japanese Sanatorium for leprosy patients, Hansen's disease was a factor in reducing the incidence of Alzheimer's disease [6]. In addition, the Japanese researchers tested dapsone-containing medicines for leprosy patients, but they were unable to find the effect of removing amyloid beta protein; thus, they proposed that Mycobacterium leprae is a major causative factor of Hansen's disease [7].…”

“…In addition, the Japanese researchers tested dapsone-containing medicines for leprosy patients, but they were unable to find the effect of removing amyloid beta protein; thus, they proposed that Mycobacterium leprae is a major causative factor of Hansen's disease [7]. Worldwide, M. leprae is considered responsible for reducing the incidence of Alzheimer's disease based on these two papers [6,7].…”

“…However, the study [6] by the Japanese Sanatorium for leprosy patients selected the target group from the 65-84 age category. When comparing and analyzing two traits, patients with lepromatous leprosy and those with tuberculosis, the leprosy patients in the 80-95 age group with the high incidence of dementia should be selected as the target group with which to compare the occurrence of dementia.…”