In a study reported in JAMA Network Open, Weinberg et al found that receipt of the bacillus Calmette-Guérin (BCG) vaccine in patients with non–muscle-invasive bladder cancer was associated with a lower risk of Alzheimer’s disease and related dementias—as well as a lower risk of mortality—compared with not being given the BCG vaccine.
Study Details
The study involved patients aged ≥ 50 years initially diagnosed between May 1987 and May 2021 and treated within the Mass General Brigham health-care system who had no history of Alzheimer’s disease and related dementias diagnosis within the first year after non–muscle-invasive bladder cancer diagnosis. The study included a 15-year follow-up of patients who received BCG vaccine treatment (n = 3,388) and controls (n = 3,079) who did not. The primary aim of the study was to determine whether BCG vaccine exposure was associated with a reduced risk of Alzheimer’s disease and related dementias, with accounting for death as a competing event.
Key Findings
Patients receiving the BCG vaccine had a lower risk of Alzheimer’s disease and related dementias vs controls (hazard ratio [HR] = 0.80, 95% confidence interval [CI] = 0.69–0.99), including a lower risk in patients aged ≥ 70 years at time of BCG vaccine treatment (HR = 0.74, 95% CI = 0.60–0.91), and a lower risk of death (HR = 0.75, 95% CI = 0.63–0.82).
In competing risks analysis, risk differences were calculated between the BCG vaccine and control groups as the differences between the cumulative incidence functions for both Alzheimer’s disease and related dementias and death without Alzheimer’s disease and related dementias. BCG vaccine use was associated with a lower 5-year risk of Alzheimer’s disease and related dementias (difference = −0.011, 95% CI = −0.019 to −0.003) and a lower 5-year risk of death in patients without earlier diagnosis of Alzheimer’s disease and related dementias (difference = −0.056, 95% CI = −0.075 to −0.037).
The investigators concluded, “In this study, [the] BCG vaccine was associated with a significantly lower rate and risk of Alzheimer’s disease and related dementias in a cohort of patients with bladder cancer when accounting for death as a competing event. However, the risk differences varied with time.”
Marc S. Weinberg, MD, PhD, of the Department of Psychiatry, and Sudeshna Das, PhD, of the Department of Neurology, Massachusetts General Hospital, are the corresponding authors for the JAMA Network Open article.
Disclosure: The study was supported by grants from the National Institutes of Health, Alzheimer’s Association, and others. For full disclosures of the study authors, visit jamanetwork.com.
