Summary: A recent study suggests that the Bacillus Calmette-Guérin (BCG) vaccine, typically used to prevent tuberculosis, may also reduce the risk of Alzheimer’s disease and related dementias.
The study followed 6,467 individuals, over 15 years post their diagnosis with non-muscle-invasive bladder cancer. Findings revealed patients who received the BCG vaccine had a 20% lower risk of Alzheimer’s disease and related dementias, and a 25% reduced risk of death.
The team is now focusing on exploring the benefits of BCG vaccination in Alzheimer’s disease-related clinical trials.
Key Facts:
- A study found that the BCG vaccine, usually used for tuberculosis, was associated with a 20% reduced risk of Alzheimer’s disease and related dementias.
- The study, involving over 6,400 individuals diagnosed with non-muscle-invasive bladder cancer, spanned 15 years.
- The BCG vaccine also demonstrated a 25% reduced risk of death in treated patients, with the protective association being more pronounced in patients aged 70 years or older.
Source: Mass General
The Bacillus Calmette-Guérin (BCG) vaccine—which prevents tuberculosis—offers multiple beneficial effects, and it’s currently a recommended therapy for non–muscle-invasive bladder cancer.
In a new study led by investigators at Massachusetts General Hospital (MGH) and Brigham and Women’s Hospital (BWH), treatment with the BCG vaccine was associated with a reduced risk of Alzheimer’s disease and related dementias.
The findings are published in JAMA Network Open.
Although previous research has suggested a link between the BCG vaccine and a lower risk of dementia, studies were limited by size, study design, or analytical methods.
To conduct a more robust study, Marc Weinberg, MD, PhD, an Instructor in Psychiatry at MGH, along with co-first authors Colin Magdamo, BS, (MGH Neurology) and Affan Zafar, MD (MGH and BWH Urology), senior author Sudeshna Das, PhD, (MGH Neurology), and colleagues followed 6,467 individuals for up to 15 years after they were diagnosed with non–muscle-invasive bladder cancer.
The group included 3,388 patients who underwent BCG vaccine treatment and 3,079 who served as controls, matched by factors such as age, sex, and medical co-morbidities.
During follow-up, 202 patients in the BCG vaccine group and 262 in the control group developed Alzheimer’s disease and related dementias.
The incidence was 8.8 per 1,000 person-years and 12.1 per 1,000 person-years in the respective groups. Analyses revealed that treatment with the BCG vaccine was associated with a 20% lower risk of Alzheimer’s disease and related dementias. The protective association was greater in patients aged 70 years or older.
Additionally, during follow-up, 751 patients in the BCG vaccine group and 973 in the control group died. Thus, treatment with BCG vaccine was associated with a 25% lower risk of death.
“A vaccine like BCG, if proven effective, is a perfect example of a cost-effective, population-health–based solution to a devastating illness like Alzheimer’s disease,” says Weinberg.
“We are shifting our focus towards studying the potential benefits of BCG vaccination of older adults in Alzheimer’s disease–related clinical trials.”
If a causal link is found, it will be important to understand the mechanisms involved. Weinberg and his colleagues note that the BCG vaccine’s effects on the immune system may play a role.
Additional co-authors include Sun Young Chung, BS; Wesley H. Chou, MD; Madhur Nayan, MD, PhD; Mayuresh Deodhar, MS; Daniel M. Frendl, MD, PhD; Adam S. Feldman, MD, MPH; Denise L. Faustman, MD, PhD; Steven E. Arnold, MD; and Bella Vakulenko-Lagun, PhD.
Funding: This work was supported by the National Institutes of Health and the Alzheimer’s Association.
About this Alzheimer’s disease research news
Author: Brandon Chase
Source: Mass General
Contact: Brandon Chase – Mass General
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Association of BCG Vaccine Treatment With Death and Dementia in Patients With Non–Muscle-Invasive Bladder Cancer” by Marc Weinberg et al. JAMA Network Open
Abstract
Association of BCG Vaccine Treatment With Death and Dementia in Patients With Non–Muscle-Invasive Bladder Cancer
Importance
The BCG vaccine—used worldwide to prevent tuberculosis—confers multiple nonspecific beneficial effects, and intravesical BCG vaccine is currently the recommended treatment for non–muscle-invasive bladder cancer (NMIBC). Moreover, BCG vaccine has been hypothesized to reduce the risk of Alzheimer disease and related dementias (ADRD), but previous studies have been limited by sample size, study design, or analyses.
Objective
To evaluate whether intravesical BCG vaccine exposure is associated with a decreased incidence of ADRD in a cohort of patients with NMIBC while accounting for death as a competing event.
Design, Setting, and Participants
This cohort study was performed in patients aged 50 years or older initially diagnosed with NMIBC between May 28, 1987, and May 6, 2021, treated within the Mass General Brigham health care system. The study included a 15-year follow-up of individuals (BCG vaccine treated or controls) whose condition did not clinically progress to muscle-invasive cancer within 8 weeks and did not have an ADRD diagnosis within the first year after the NMIBC diagnosis. Data analysis was conducted from April 18, 2021, to March 28, 2023.
Main Outcomes and Measures
The main outcome was time to ADRD onset identified using diagnosis codes and medications. Cause-specific hazard ratios (HRs) were estimated using Cox proportional hazards regression after adjusting for confounders (age, sex, and Charlson Comorbidity Index) using inverse probability scores weighting.
Results
In this cohort study including 6467 individuals initially diagnosed with NMIBC between 1987 and 2021, 3388 patients underwent BCG vaccine treatment (mean [SD] age, 69.89 [9.28] years; 2605 [76.9%] men) and 3079 served as controls (mean [SD] age, 70.73 [10.00] years; 2176 [70.7%] men). Treatment with BCG vaccine was associated with a lower rate of ADRD (HR, 0.80; 95% CI, 0.69-0.99), with an even lower rate of ADRD in patients aged 70 years or older at the time of BCG vaccine treatment (HR, 0.74; 95% CI, 0.60-0.91). In competing risks analysis, BCG vaccine was associated with a lower risk of ADRD (5-year risk difference, −0.011; 95% CI, −0.019 to −0.003) and a decreased risk of death in patients without an earlier diagnosis of ADRD (5-year risk difference, −0.056; 95% CI, −0.075 to −0.037).
Conclusions and Relevance
In this study, BCG vaccine was associated with a significantly lower rate and risk of ADRD in a cohort of patients with bladder cancer when accounting for death as a competing event. However, the risk differences varied with time.
