Men with benign prostatic hyperplasia have an elevated risk of developing Alzheimer's disease and all-cause dementia, according to researchers who speculate that disturbed sleep may be a contributing factor. The study examined data on 297,026 Danish men with benign prostatic hyperplasia (BPH) who were identified based on surgical or medical treatment for the condition, as well as a control group of 1.12 million men in the general Danish population without BPH matched by birth year. Median follow-up starting one year after the prostate diagnosis or index date was 6.9 years for men with BPH and 6.4 years for the comparison group. During the study period, a total of 7,909 men with BPH developed incident dementia from any cause, including 3,603 cases of Alzheimer's disease, compared with 24,745 men in the general population cohort who developed dementia, and 9,946 who had Alzheimer's. The cumulative risk of Alzheimer's disease from years 1 to 10 of follow-up was 1.55 per 1,000 person-years among men with benign prostatic hyperplasia compared with 1.25 per 1,000 person-years among the other men in the study. This translated into a significantly higher risk of Alzheimer's disease for men with benign prostatic hyperplasia in years 1 to 10 of follow-up (adjusted hazard ratio 1.16), as well as during years 10 through 21 (aHR 1.10). "Our analyses suggest that Danish men with benign prostatic hyperplasia face modestly increased risks of Alzheimer's disease and dementia," said senior study author Victor Henderson, a professor of epidemiology and population health and of neurology and neurological sciences at Stanford University, in California. It's possible that this is due to reduced quality or quantity of sleep because men with benign prostatic hyperplasia tend to go to the bathroom more often during the night, resulting in more fragmented sleep, Henderson said by email. "Our analyses do not prove, however, that disrupted sleep is the underlying cause," Henderson said. "It may or may not be." One limitation of the study is that researchers lacked data on the frequency or severity of any lower urinary tract symptoms among men with BPH, the study team notes in EClinicalMedicine. This made it impossible to examine whether nocturia severity might be tied to dementia risk. Men with benign prostatic hyperplasia might also have more contact with the healthcare system, leading to a higher likelihood that dementia could be detected sooner than among men who seek care less frequently, the researchers point out. Benign prostatic hyperplasia is only one cause of poor sleep, making it possible that other factors such as stress, sleep disorders, poor sleep hygiene, or other lifestyle factors are involved, said Matthew Pase, a researcher at Monash University in Melbourne, Australia, and Harvard T.H. Chan School of Public Health in Boston. "Poor sleep is thought to impair the brain's ability to remove toxic waste, which may contribute to the development of dementia, and sleep disordered breathing may also lead to hypoxic brain injury," Pase, who wasn't involved in the study, said by email. "However, dementia also leads to problems with sleep." Although more research is still needed on the connection between benign prostatic hyperplasia and dementia, the study results suggest that this link should be on clincicians' radar, said Dr. Yue Leng, an assistant professor in psychiatry and behavioral sciences at the University of California, San Francisco who wasn't involved in the study. "Given that sleep disturbances might further contribute to increased risk of Alzheimer's disease, these sleep disturbances should be better managed and non-pharmacological treatment should be prioritized," Dr. Yue said by email. —Lisa Rapaport Source
