Interaction Of Apolipoprotein E Genotypes, Lifestyle Factors And Future Risk Of Dementia-Related Mortality: The Cohort Of Norway (Conor)

Background/Aims: Our aims were two-fold: firstly, to investigate the association and interaction between apolipoprotein E (ApoE), lifestyle risk factors and dementia-related mortality and, secondly, to examine if using dementia-related mortality yielded comparable risk estimates for the ApoE genotypes as reported in studies using a clinical dementia diagnosis as the end point. Methods: We used a nested case-control study with 561 cases drawn from dementia deaths in the Cohort of Norway (CONOR) and 584 alive controls. Results: ApoE epsilon 4 carriers were at increased risk of dementia-related mortality compared to noncarriers [odds ratio (OR) 2.46, 95% confidence interval (CI) 1.93-3.13], and epsilon 4 homozygotes were at particularly high risk (OR 7.86, 95% CI 3.80-13.8), while the epsilon 2 type was associated with a lower risk. The highest risk of dementia-related mortality was found among epsilon 4 carriers with more lifestyle risk factors (epsilon 4 carriers who were smokers, hypertensive, physically inactive and diabetics) versus epsilon 4 noncarriers without lifestyle risk factors (OR 15.4, 95% CI 4.37-52.4). The increased risk was additive, not multiplicative. Conclusions: Ensuring a healthy lifestyle is important to be able to prevent dementia in populations at large, but especially for epsilon 4 carriers. Using dementia mortality gives comparable results for the ApoE-dementia association as studies using clinical dementia diagnoses. (C) 2015 S. Karger AG, Basel