Systemic and localized extra-central nervous system bacterial infections and the risk of dementia among US veterans: A retrospective cohort study

Abstract

IntroductionEmerging evidence indicates associations between extra-central nervous system (CNS) bacterial infections and an increased risk for dementia; however, epidemiological evidence is still very limited. MethodsThis study involved a retrospective cohort of a national sample of US veterans (N = 417,172) aged ≥56 years. Extended Cox proportional hazard models adjusted for demographic characteristics and medical and psychiatric comorbidities determined the associations between systemic and localized extra-CNS bacterial infections occurring >2 years before the initial dementia diagnosis and the risk for dementia. ResultsExposure to any extra-CNS bacterial infection was associated with a significantly increased risk for dementia (hazard ratio [HR] = 1.20 [95% confidence interval = 1.16–1.24]). Independently, septicemia (HR = 1.39 [1.16–1.66]), bacteremia (HR = 1.22 [1.00–1.49]), osteomyelitis (HR = 1.20 [1.06–1.37]), pneumonia (HR = 1.10 [1.02–1.19]), urinary tract infections (HR = 1.13 [1.08–1.18]), and cellulitis (HR = 1.14 [1.09–1.20]) were associated with a significantly increased risk for dementia. DiscussionBoth systemic and localized extra-CNS bacterial infections are associated with an increased risk for developing dementia.