Elevated C-reactive protein and late-onset bipolar disorder in 78 809 individuals from the general population

Abstract

BackgroundNo prospective studies have examined the role of C-reactive protein (CRP) in late-onset bipolar disorder.AimsWe tested the hypothesis that elevated levels of CRP are associated cross-sectionally and prospectively with late-onset bipolar disorder, and that such an association possibly is causal.MethodWe performed cross-sectional and prospective analyses with a median follow-up time of 5.9 years (interquartile range: 4.4– 7.6) in 78 809 individuals from the general population, and used genetic variants influencing CRP levels to perform a Mendelian randomisation study.ResultsElevated levels of CRP were associated both cross-sectionally and prospectively with late-onset bipolar disorder. When CRP was on a continuous scale, a doubling in CRP yielded an observational odds ratio for late-onset bipolar disorder of 1.28 (1.08–1.52) with a corresponding causal odds ratio of 4.66 (0.89–24.3).ConclusionElevated CRP is associated with increased risk of late-onset bipolar disorder in the general population which was supported by the genetic analysis.