Prevalence and pattern of cognitive impairment in a community cohort of men in South Wales: methodology and findings from the Caerphilly Prospective Study.

BACKGROUND/AIMS: The prevalence of dementia and cognitive impairment not dementia was investigated in the Caerphilly Prospective Study cohort (men currently aged 65-84 years). METHODS: Of 1,633 men eligible for cognitive screening, 1,225 (75%) were seen, with those failing the screening criteria (CAMCOG <83 or decline in CAMCOG >9) being neurologically examined. RESULTS: For dementia, diagnosed by DSM-IV criteria, the population prevalence was 5.2% rising to 6.1% in the screened population. For cognitive impairment not dementia, the prevalence in the screened population was 15.6% giving an overall prevalence of cognitive impairment of 21.8%. Prevalence rose fivefold between ages of 65 and 84 years to reach over 50%. CONCLUSION: These figures are likely to underestimate actual prevalence in this population, and developing effective interventions should be a public health priority.