Abstract
BACKGROUND: Alzheimer's disease (AD) is related to higher mortality but it is not entirely evident which causes of death explain this. The objective of this study was to assess the causes of death in a nationwide cohort of clinically verified AD cases and compare the causes to a matched comparison cohort without AD. METHODS: Cohort of all community-dwellers with clinically verified AD residing in Finland on 31 December 2005 (n = 27,948) and a matched comparison cohort without AD (n = 27,948). Mortality (2006-2012, n = 30,641, 54.8%) and causes of death were obtained from register. Cause of death was ascertained with clinical examination (87.3% of deaths), forensic (8.0%) or medical autopsy (4.7%). RESULTS: In AD cohort, the most common causes were diseases of the nervous system (49.9%), circulatory system (31.7%) and neoplasms (7.7%), while diseases of circulatory system (53.5%), neoplasms (19.1%) and mental and behavioral disorders (7.3%) contributed for majority of deaths in the comparison cohort. There were no sex-wise differences. People with AD were over 20 times more likely to die due to diseases of the nervous system (OR, 95% CI 22.06, 19.87-24.25) than the comparison cohort, while other causes, e.g., diseases of the circulatory system (0.40, 0.38-0.42), neoplasms (0.35, 0.33-0.38), mental and behavioral disorders (0.27, 0.24-0.30) and external causes of morbidity and mortality (0.72, 0.62-0.81) were less common in the AD cohort. CONCLUSIONS: Although half of the people with AD died due to diseases of the nervous system, cancers and especially cardio/cerebrovascular diseases were still important contributors to the overall mortality among them. This should be acknowledged when planning their terminal care.