BACKGROUND: Copeptin is a reliable surrogate marker for the neurohypophyseal hormone vasopressin. Elevated plasma level of copeptin has been associated with cardiovascular and metabolic disease risk.

OBJECTIVE: To investigate the association between copeptin and risk of dementia.

METHODS: In all, 18,240 individuals from Malmö, Sweden, were examined between 2002 and 2006 (mean age 69.3 years, 69.8% men). Incident cases of dementia until 31 December 2009 were identified by linkage with the Swedish National Patient Register. To validate the dementia diagnoses, medical records as well as laboratory and neuroimaging data were carefully reviewed. Baseline level of copeptin was measured in frozen plasma in: (1) all participants who were diagnosed with dementia during follow-up, (2) a random sample of 5100 individuals of the cohort.

RESULTS: During a median follow-up of 4.2 years, there were 374 incident dementia cases (age range 60-83 years at baseline): 120 were classified as Alzheimer's disease (AD), 84 as vascular dementia (VaD), and 102 as mixed dementia. In logistic regressions adjusted for cardiovascular risk factors, baseline level of copeptin predicted incident VaD (Odds ratio (OR) 1.30 per 1 SD increase in log copeptin, 95% CI 1.03-1.64). Copeptin did not predict incidence of all-cause dementia (OR 1.05, 95% CI 0.94-1.18), AD (OR 0.97, 95% CI 0.79-1.18), or mixed dementia (OR 0.85, 95% CI 0.68-1.05).

CONCLUSION: Elevated plasma level of copeptin is a risk marker for incident VaD, but not for incident AD. This suggests that the vasopressin hormonal system might be involved in the development of VaD.