Virus exposure and neurodegenerative disease risk across national biobanks

Abstract

ABSTRACTBACKGROUNDWith recent findings connecting Epstein-Barr virus to increased risk of multiple sclerosis and growing concerns regarding the potential neurological impact of the coronavirus pandemic, we surveyed biobank scale real-world data to identify potential links between viral exposures and neurodegenerative disease risks.METHODSTo assess the potential increased risk of neurodegenerative diseases due to viral exposures, we mined time series data from FinnGen as a discovery dataset and cross-sectional data from the UK Biobank as a replication dataset for 73 pairs of common viral exposures and neurodegenerative disease outcomes. We investigated the impact of time span between viral exposure and disease risk using time series data from FinnGen at 1, 5, and 15 year intervals between exposure and disease onset. This analysis helped us to avoid the potential confounding of concurrent diagnosis due to hospitalization with viral infection. Further, to address the possible bias of reverse causality we examined risk for severe viral infections after NDD diagnosis.RESULTSWe identified 45 viral exposures significantly associated with increased risk of post-exposure neurodegenerative disease onset after multiple test correction in the discovery phase using longitudinal data. 22 of these associations were replicated in cross sectional data from the UK Biobank. The largest effect association we saw replicated was between viral encephalitis exposure and Alzheimer’s disease, with discovery hazard estimates of ∼30 and a replication odds ratio of ∼22. We also replicated the association between Epstein-Barr virus exposure and multiple sclerosis 5-15 years before diagnosis of multiple sclerosis. In total, 17 virus/neurodegeneration pairs were significant with 5-15 years between viral exposure and NDD diagnosis. In an investigation of potential confounding and reverse causality, we generally see larger hazard ratios associated with viruses preceding NDD diagnosis than viruses post NDD diagnosis.CONCLUSIONSViral exposures contribute to later in life risk of neurodegenerative disease with increased risk of neurodegeneration still significant at up to 15 years between some events in this report.