Treatment with androgen deprivation therapy (ADT) was not associated with an increased risk of dementia in a large, population-based study, according to investigators.
Previous studies have demonstrated that low testosterone levels are associated with cognitive impairment and Alzheimer’s disease, but the association between ADT and cognitive impairment remains controversial, with conflicting results being reported.
In the current large population-based study, compared with nonuse, treatment with ADT did not increase the risk of dementia (incidence, 7.4 vs. 4.4 per 1,000 person years, adjusted hazard ratio, 1.02; 95%CI, 0.87-1.19), reported Farzin Khosrow-Khavar, PhD, of McGill University, Montreal, and colleagues.
“Consistent with our findings, a recent meta-analysis found that although patients treated with ADT performed worse on visuomotor tasks in comparison with control subjects or their own baseline assessments, there were no significant differences in cognitive domains that are pertinent to dementia including performance on attention/working memory, executive function, language, verbal memory, visual memory, and visuospatial ability” they wrote (J Clin Oncol. 2016 Nov. 21 doi: 10.1200/JCO.2016.69.6203).
In a smaller study of 9,272 patients, recently published in JAMA Oncology, prostate cancer patients treated with ADT were more than twice as likely as were those who were not to develop dementia.
For the current study, investigators identified a cohort of 30,903 men who were newly diagnosed with nonmetastatic prostate cancer between April 1, 1988, and April 30, 2015, using the United Kingdom’s Clinical Practice Research Datalink. The patients were then observed until April 30, 2016.
Within this cohort, 799 patients were newly diagnosed with dementia, which extrapolated to a crude incidence of 6.0 per 1,000 person-years. During the follow-up period, 17,994 patients (58.2%) were treated with ADT, and the median duration of use was 2.3 years.
Men who were using ADT tended to be older and were more likely to have ever used tobacco products, and they were also more likely to have had higher prostate-specific antigen levels and a higher prevalence of comorbidities, compared with nonusers.
In the primary analysis, ADT use was not associated with an overall higher risk of developing dementia (adjusted HR, 1.02; 95% CI, 0.87-1.19).
In secondary analyses, the risk did not vary with cumulative duration of use. Findings were similar when the risk was assessed by the type of ADT used for treatment, and when the association was evaluated with Alzheimer’s disease (adjusted HR, 1.11; 95% CI, 0.85-1.44) versus other types of dementia (adjusted HR, 0.97; 95% CI, 0.80-1.18).
The authors noted that additional studies in different settings are needed to confirm these new findings.
The study was supported by a foundation grant from the Canadian Institutes of Health Research. The authors declared that there were no conflicts of interest.