High-sensitivity cardiac troponin I and NT-proBNP as predictors of incident dementia and Alzheimer's disease: the FINRISK Study.

Cardiac troponin and N-terminal pro-brain natriuretic peptide (NT-proBNP) are known to associate with incident dementia. The purpose of our study was to examine whether high-sensitivity cardiac troponin I (hs-TnI) and NT-proBNP are associated with incident dementia and Alzheimer's disease (AD) independently of each other. Our study was a part of the national population-based health examination survey, FINRISK 1997, with a total sample of 7114 subjects, including 407 incident dementia cases and 319 AD cases during the follow-up time of 18 years. Using multivariate Cox regression analyses, we calculated the hazard ratios (HR) for hs-TnI and NT-proBNP. Analyses were adjusted for the previously known dementia/AD risk factors, including the apoE genotype. NT-proBNP was independently associated with incident dementia (HR 1.32, 95% CI 1.17-1.49) and AD (HR 1.30, 95% CI 1.13-1.5). Hs-TnI was also associated with incident dementia (HR 1.12, 95% CI 1.02-1.23), but not independent of NT-proBNP (HR 1.10, 95% CI 0.99-1.21). Hs-TnI was not associated with incident AD. The results remained similar in cause-specific Cox regression models and among subjects over 40 years of age. NT-proBNP and hs-TnI improved the reclassification of dementia risk in 10 years follow-up, and hs-TNI also in 18 years of follow-up. Neither hs-TnI nor NT-proBNP was able to outperform each other in risk reclassification of dementia. Both cardiovascular biomarkers, NT-proBNP and hs-TnI, were associated with incident dementia independently of traditional dementia risk factors including the apoE genotype. NT-proBNP was also associated with AD. Both markers offered a better dementia risk reclassification compared with traditional risk factors.