Epidemiology of head trauma and neurocognitive impairment in a multi-ethnic population

This study tested two hypotheses. These were: (1) that mild cognitive impairment of the type that may characterize early-onset dementia of the Alzheimer type varies by ethnic group among the noninstitutionalized elderly, and (2) that head trauma is a risk factor associated with the development of this disease. The study sample consisted of a cohort of 2,105 Black, Mexican-American and White subjects aged 45 years and over at baseline in 1985-1987 in San Diego, Calif. Intellectual functioning was measured by Pfeiffer's Short Portable Mental Status Questionnaire. Percent prevalence of test failure after Pfeiffer's adjustment for education and ethnicity was highest for Whites (5.7%, CI = 4.26, 7.57) and lowest for Blacks (1.3%, CI = 0.61, 2.63), with Mexican-Americans intermediate (3.5%, CI = 2.28, 5.29). The difference between Blacks and Whites was statistically significant at the 0.05 level. Females failed more often (4.2%, CI = 3.15, 5.56) than males (3.1%, CI = 2.13, 4.47) across all ethnic groups, but the difference was not statistically significant after Pfeiffer's adjustment for education and ethnicity. Self-reported head traumas and other possible risk factors for dementia of the Alzheimer type were examined by logistic regression in a case-control analysis. A statistically significant association (OR = 8.577, CI = 3.056, 24.064) was noted for those with mild intellectual impairment who reported head traumas in a multivariate environment.