Distribution of major dementias by race and sex in South Carolina.

Preliminary data from the newly implemented Registry for dementing illnesses was used to examine the distribution of four types of dementia in black and white residents of South Carolina. The data for 1464 subjects were abstracted by field research nurses in state mental health facilities. Overall, 649 patients (44.3%) were black and 765 (52.3%) were white. Women comprised 53.8% of all cases of dementia in this study. The overall distribution included 66% Alzheimer's disease (AD), 12% multi-infarct dementia (MID), 10% alcoholic dementia (ALC), nine percent other-medical and three percent other-unspecified. Though the proportion of blacks does not exceed one-third of the total population of S.C., blacks comprised 44.3% of all cases of dementia. AD accounted for 79% of all cases of dementia in women, but only 51% of such cases in demented men, who showed an apparent preoponderance of MID and alcoholic dementia. The frequency distribution of MID was equal in blacks and whites. Educational level had no discernible effects. Though not directly comparable, these preliminary findings are similar to those of the Copiah County Study, including a higher frequency of AD with advancing age.