Prevalence of "organic brain syndrome" in a Southern European population in two different time periods. The ZARADEMP Project

Abstract

Background: Comparative studies of dementia in different time periods are quite limited in the international literature, but might be useful to test environmental hypotheses. The aim of this study is to compare the prevalence of "organic brain syndrome", as a measure of dementia, in the elderly living in the same community in two different time periods and using the same methods. Methods: Representative samples of the elderly in the Zaragoza Study or ZARADEMP 0 (n= 1,080), completed the past decade, and now in Wave I of the ZARADEMP Project or ZARADEMP I (n= 4,803) were interviewed. The Geriatric Mental State (GMS) was the main case-finding instrument and the results were analysed using the AGECAT diagnostic package to generate diagnoses. Results: Adjusted, total prevalence of "organic brain syndrome" in individuals aged 65 years and older has not varied from the previous decade. It was 8.4% in ZARADEMP I, and 7.4% in ZARADEMP 0 (prevalence ratio, PR = 0.83; CI 0.65-1.07). Adjusted prevalence among men was lower in ZARADEMP I (3.6%) when compared to ZARADEMP 0 (5.5%), although the differences do not reach statistically significance (PR= 0.65; CI 0.41-1.05). However, in support of the working hypothesis, the differences were more marked, and we consider they reach statistically significant proportions in the age group 80-84 years. Conclusions: The prevalence of "organic brain syndrome" has not increased from the previous decade. On the contrary, the prevalence tends to be lower in men, and the differences reach stastistical significance in the age group 80-84 years. New analysis using diagnostic criteria of dementia in the same sample are required to confirm these findings.