TOPLINE:
Patients aged 50 years or older with clinically apparent Helicobacter pylori infection (CAHPI) have an 11% increased risk for Alzheimer's disease (AD), results of a large and lengthy population-based study suggest.
METHODOLOGY:
- Researchers identified all cases with a first-time diagnosis of AD and matched each AD case to up to 40 AD-free control cases on the basis of age, sex, cohort entry date, and duration of follow-up.
- The exposure of interest was CAHPI, defined based on an algorithm using clinical guidelines and recommendations on the management of HP infection, with researchers focusing on infected individuals presenting with symptoms or developing serious complications from the infection.
- Researchers performed several sensitivity analyses, which included repeating the primary analysis using alternate lag periods, restricting the cohort to participants with AD (not vascular, alcoholic, and unspecified dementia), and using salmonellosis, an infection not previously associated with AD, as a negative control exposure.
TAKEAWAY:
- Compared with no exposure to CAHPI, exposure to CAHPI was associated with a moderately increased risk for AD (odds ratio [OR], 1.11; 95% CI, 1.01-1.21), with no major effect modification by demographics or socioeconomic status.
- The increased risk peaked 7.3-10.8 years after CAHPI onset (OR, 1.24; 95% CI, 1.05-1.47) before decreasing.
- Sensitivity analyses yielded findings that were overall consistent with those of the primary analysis.
- The analysis with salmonellosis as a negative control exposure showed no association with the risk for AD (OR, 1.03; 95% CI, 0.82-1.29).
IN PRACTICE:
"These results support the notion of HP infection as a potential modifiable risk factor of AD" and "pave the way for future randomized controlled trials that would assess the impact and cost-effectiveness of population-based targeted interventions such as individualized HP eradication programs, on the development of AD," the authors write.
SOURCE:
The study was conducted by Antonios Douros ,Department of Medicine, and Department of Epidemiology, Biostatistics, and Occupational Health, McGill University, Montreal, Quebec, Canada, and colleagues. It was published online December 13, 2023 in Alzheimer's & Dementia.
LIMITATIONS:
Given the observational nature of the study, residual confounding is possible. Because the exposure definition was on the basis of CAHPI recorded by general practitioners, exposure misclassification due to symptomatic patients not seeking primary care is possible, as is outcome misclassification. The authors can't rule out the possibility of an association between asymptomatic H pylori infection and AD risk.
DISCLOSURES:
The study received funding from the Canadian Institutes of Health Research. Douros has no relevant conflicts of interest; see paper for disclosures of other authors.
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