Objective: To determine the risk factors associated with dementia with Lewy bodies (DLB).
Methods: We identified 147 subjects with DLB and sampled 2 sex- and age-matched cognitively normal control subjects for each case. We also identified an unmatched comparison group of 236 subjects with Alzheimer disease (AD). We evaluated 19 candidate risk factors in the study cohort.
Results: Compared with controls, subjects with DLB were more likely to have a history of anxiety (odds ratio; 95% confidence interval) (7.4; 3.5-16; p < 0.0001), depression (6.0; 3.7-9.5; p < 0.0001), stroke (2.8; 1.3-6.3; p = 0.01), a family history of Parkinson disease (PD) (4.6; 2.5-8.6; p < 0.0001), and carry APOE ε4 alleles (2.2; 1.5-3.3; p < 0.0001), but less likely to have had cancer (0.44; 0.27-0.70; p = 0.0006) or use caffeine (0.29; 0.14-0.57; p < 0.0001) with a similar trend for alcohol (0.65; 0.42-1.0; p = 0.0501). Compared with subjects with AD, subjects with DLB were younger (72.5 vs 74.9 years, p = 0.021) and more likely to be male (odds ratio; 95% confidence interval) (5.3; 3.3-8.5; p < 0.0001), have a history of depression (4.3; 2.4-7.5; p < 0.0001), be more educated (2.5; 1.1-5.6; p = 0.031), have a positive family history of PD (5.0; 2.4-10; p < 0.0001), have no APOE ε4 alleles (0.61; 0.40-0.93; p = 0.02), and to have had an oophorectomy before age 45 years (7.6; 1.5-39; p = 0.015).
Conclusion: DLB risk factors are an amalgam of those for AD and PD. Smoking and education, which have opposing risk effects on AD and PD, are not risk factors for DLB; however, depression and low caffeine intake, both risk factors for AD and PD, increase risk of DLB more strongly than in either.