Infectious diseases are suggested to increase the long-term risk of dementia, including AD.2 This is supported by research of hospital-treated infections, with evidence that infections occurring more than 10 years before the onset of dementia may also be associated with excess risk.2 Of hospital-treated infections, infections of the central nervous system (CNS) are associated with the highest risk.2 However, increased risk of dementia is not limited to CNS infections.2 Common infections, such as sepsis and pneumonia, have also been associated with an increased risk of dementia, suggesting that systemic inflammation is sufficient to impact the brain.2,5 Some non-hospital treated infections have been studied for their relation to AD, such as periodontitis (gum disease) and other oral diseases.6,7 Patients with serious infections may become frail, which is associated with a poor inflammatory response and slower recovery after infections.5 As a result, frailty may increase a patient’s risk of dementia and vulnerability to the development of comorbidities.5
References:
1.Janbek J, Frimodt-Møller N, Laursen TM, Waldemar G. Dementia identified as a risk factor for infection-related hospital contacts in a national, population-based and longitudinal matched-cohort study. Nat Aging 2021; 1 (2): 226–233.
2.Sipilä PN, Heikkilä N, Lindbohm JV, et al. Hospital-treated infectious diseases and the risk of dementia: a large, multicohort, observational study with a replication cohort. Lancet Infect Dis 2021; 21 (11): 1557–1567.
3.Janbek J, Frimodt-Møller N, Laursen TM, Waldemar G. Hospital readmissions following infections in dementia: a nationwide and registry-based cohort study. Eur J Neurol 2021; 28 (11): 3603–3614.
4.Janbek J, Taudorf L, Musaeus CS, et al. Increased short- and long-term mortality following infections in dementia: a nationwide registry-based cohort study. Eur J Neurol 2021; 28 (2): 411–420.
5.Muzambi R, Bhaskaran K, Smeeth L, et al. Assessment of common infections and incident dementia using UK primary and secondary care data: a historical cohort study. Lancet Healthy Longev 2021; 2 (7): e426–e435.
6.Teixeira FB, Saito MT, Matheus FC, et al. Periodontitis and Alzheimer’s disease: a possible comorbidity between oral chronic inflammatory condition and neuroinflammation. Front Aging Neurosci 2017; 9: 327.
7.Pruntel SM, van Munster BC, de Vries JJ, et al. Oral health as a risk factor for Alzheimer disease. J Prev Alzheimers Dis 2023: 1–10. https://doi.org/10.14283/jpad.2023.82
