To perform a quantitative meta-analysis examining the frequency of vascular risk factors (VRFs) in dementia with Lewy bodies (DLB) versus Alzheimer’s disease (AD).

The relationship between AD and VRFs has been widely studied. VRFs in DLB have received less attention. Results of research on the frequency of VRFs in DLB have been mixed, with some studies demonstrating a lower frequency of certain VRFs, some reporting higher frequency, and others with generally equivalent rates in DLB and AD.

We conducted a systematic review and meta-analysis of observational cohort studies which reported data on frequency of diabetes, smoking history, hypertension, and hyperlipidemia in patient groups with clinical diagnoses of DLB and AD. PubMed, MEDLINE, and PsychInfo databases were searched for articles published up to June 2019, yielding a total of 60 studies, 12 of which met inclusion criteria.  

DLB had an 18% lower risk of having a history of diabetes (RR=0.82, k=12, 95%CI=0.71–0.95, Z=-2.675, p=0.007) and 17% higher risk of history of cigarette smoking (RR=1.17, k=7, 95% CI=1.04–1.33, Z=2.55, p=0.001) compared to AD. Heterogeneity analyses did not reach statistical significance for diabetes or smoking history, indicating low between study variance. Ninety-five percent confidence intervals for risk ratios of hypertension (RR=0.92, k=9, 95%CI=0.85–1.006) and hyperlipidemia (RR=0.99, k=7, 95%CI=0.90–1.19) included a value of 1 and did not demonstrate significant heterogeneity across studies, suggesting comparable frequency in DLB and AD.

Diabetes was statistically more frequent in DLB and smoking history more frequent in AD, while frequency of hypertension and hyperlipidemia did not significantly differ between groups. Homogeneity of effects was observed across studies for each VRF. Our novel results raise the possibility that specific vascular risk factors differ in intensity between AD and DLB. Further research is needed to confirm this, and to better understand the underlying pathobiological mechanisms.