Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyFebruary 2023
A population-based study suggests a modest association – consistent with previous randomised-trial findings.
When results of the Women’s Health Initiative (WHI) randomised trials of oral menopausal hormone therapy (HT) were publicised 20 years ago, attention focused mostly on excess adverse thromboembolic and cardiovascular events, as well as breast cancer. But these trials also showed that HT was associated with excess risk for dementia (JAMA 2003; 289: 265-162; JAMA 2004; 291: 2947-2958). To examine whether this association existed in a community setting, researchers conducted a population-based, observational study drawn from Taiwan’s single-payer health insurance database.
About 35,000 women who initiated menopausal HT between the years 2000 and 2005 were compared with 70,000 who did not. The two cohorts were propensity matched on age and comorbidities, and additional statistical analysis was adjusted for residual differences. During average follow up of 12 years, the cumulative incidence of dementia was significantly higher in the HT group than in the control group (20.0 vs 15.8 cases/1000 women; adjusted hazard ratio, 1.35), or roughly one additional case per 250 HT recipients. A dose response relation was noted.
Comment: These observational findings are consistent with the randomised WHI findings: HT seems to modestly increase risk for dementia. Unfortunately, in the current study, researchers did not distinguish between oral and nonoral routes of HT administration, but I suspect that oral dosing predominated, given that many of these women started HT longer than 20 years ago. A potential small excess risk for dementia should be included in discussions with women who are considering HT for symptom relief.
ALLAN S. BRETT, MD
Clinical Professor of Medicine, University of Colorado School of Medicine, Aurora, USA.
Sung Y-F, et al. Use of hormone replacement therapy and risk of dementia: a nationwide cohort study. Neurology 2022; 99: e1835.
This summary is taken from the following Journal Watch title: General Medicine