Shingles, Zostavax vaccination and risk of developing dementia: a nested case-control study-results from the UK Biobank cohort.

OBJECTIVES To investigate the association between shingles and dementia, and between Zostavax vaccination and dementia. DESIGN Nested case-control study. SETTINGS Data were drawn from the UK Biobank cohort study with a total of 228 223 participants with Hospital Episodes Statistics and primary care linkage health records. PARTICIPANTS The analyses included 2378 incident dementia cases and 225 845 controls. Inclusion criteria for incident cases were a dementia diagnosis 3 years or more after the first assessment date derived from all sources including International Classification of Diseases (ICD)-10, ICD-9, self-report and primary care linkage records. Subjects with no dementia code from all sources were coded as controls. Both shingles and Zostavax vaccination were investigated for their association with dementia risk. RESULTS There was a small but non-significant increase in the risk of dementia in subjects with shingles diagnosed 3 years or more prior to dementia diagnosis (OR: 1.088 with 95% CI: 0.978 to 1.211). In those subjects who had had Zostavax vaccination, the risk of dementia significantly decreased (OR: 0.808 with 95% CI: 0.657 to 0.993). CONCLUSION A history of shingles was not associated with an increased risk of dementia. In subjects who were eligible for the immunisation and vaccinated with Zostavax, we saw reduced risk of developing dementia.