B-type natriuretic peptide as a predictor of declining cognitive function and dementia-a cohort study of an elderly general population with a 5-year follow-up

Background. Several traditional cardiovascular risk factors assessed in the middle-aged are associated with the risk of dementia, but they are known to lose much of their prognostic value when measured in the elderly. The aim of the study was to compare B-type natriuretic peptide (BNP) with previously known risk markers for dementia in their association with cognitive decline and dementia during a follow-up. Methods. A total of 464 subjects free of dementia aged 75 years or more were examined and followed up for 5 years in a prospective population-based stratified cohort study. The association of clinical variables to base-line Mini Mental State Examination score (MMSE), the decline of MMSE, and onset of dementia during the follow-up were examined. Results. The only variable to significantly associate with the decline of MMSE was BNP (beta 0.140; P = 0.019). A total of 59 new cases of dementia were diagnosed after the follow-up. Significant predictors of the occurrence of dementia over the study period were BNP (adjusted odds ratio (OR) 1.53; 95% confidence interval (CI) 1.09-2.16; P = 0.013), length of education (OR 0.50; 95% CI 0.33-0.77; P = 0.001), and diagnosis of hypertension (OR 0.53; 95% CI 0.27-0.95; P = 0.036). BNP remained as a significant predictor of dementia and the decline of MMSE even after adjustment to the base-line MMSE. Conclusions. BNP is an independent harbinger of the cognitive decline and incidence of new onset of dementia in an elderly general population. This is a ground for testing the impact of antihypertensive treatment in the prevention of cognitive impairment in those with elevated BNP.