The prevalence of dementia in a population-based study carried out in Granarolo, Ravenna

Abstract

To evaluate the prevalence of dementia among persons born in the year 1930 or before, who were living in Granarolo, Ravenna province, on December 31, 1991. Population study, carried out in two phases: in the first was phase all persons were administered two screening tests for dementia. In the second phase, persons who screened positive underwent detailed clinical and cognitive assessments. The Mini Mental State Examination (MMSE) and the Global Deterioration Scale (GDS) were administered as screening tests. In the second phase the screened-positive subjects underwent a general and neurological examination, and a detailed neuropsychological assessment. Of the 557 participants, 56 were clinically diagnosed as demented. Twenty-nine persons were diagnosed as affected by Alzheimer's disease (AD) and 14 patients by vascular dementia (VaD). The crude prevalence ratios for dementia were 9.1% (95% C.I. = 5.29-12.89) for men and 12.7% (95% C.I. = 8.84-16.6) for women. The prevalence of all dementias, as well as AD, increased steeply every five years of age for both men and women up to 90 years of age. Women had higher prevalence of all dementias and AD than men, more evident in the advanced ages. Our findings are in agreement with similar studies carried out in European populations, showing that prevalence of dementia increases with increasing age. If we consider that in Italy the oldest (those 80 years and older) are the fastest growing part of the elderly population, we can expect that dementia will be a major emerging public health problem, as it is one of the most common diseases in the very elderly and a major cause of disability and mortality.