Patients with bladder cancer treated with Bacillus Calmette-Guérin (BCG) have a lower risk of developing dementia, a new study finds.

In a systematic review and meta-analysis of 5 studies published from 2019 to 2023 involving 45,407 patients with bladder cancer, those exposed to intravesical BCG had a 45% decreased risk of dementia compared with those not treated with BCG, Mao-Shui Wang, MD, of Shandong Public Health Clinical Center, Shandong University in Jinan, China, and colleagues reported in Frontiers in Aging Neuroscience. The risk for Alzheimer disease was a significant 43% lower. Patients aged 75 years or older and those receiving more than 6 BCG doses particularly had decreased dementia risks.

The 5 retrospective studies were of high-quality and had a low risk for bias.

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More research is needed, according to Dr Wang’s team. Previous research has suggested that intravesical BCG instillation may increase the regulatory T cell population and increase glucose utilization and thus reverse cognitive aging, or reduce neuroinflammation.


Han C, Wang J, Chen Y-L, Guan CP, Zhang YA, Wang MS. The role of Bacillus Calmette-Guérin administration on the risk of dementia in bladder cancer patients: a systematic review and meta-analysis. Front Aging Neurosci. Published online August 24, 2023. doi:10.3389/fnagi.2023.1243588