Postmenopausal hormone therapy and Alzheimer disease: A prospective cohort study

OBJECTIVE: To explore the association between postmenopausal hormone therapy (HT) and Alzheimer disease (AD). METHODS: Twenty-year follow-up data from the Kuopio Osteoporosis Risk Factor and Prevention study cohort were used. Self-administered questionnaires were sent to all women aged 47–56 years, residing in Kuopio Province starting in 1989 until 2009, every 5th year. Register-based information on HT prescriptions was available since 1995. Probable AD cases, based on DSM-IV and National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer's Disease and Related Disorders Association criteria, were identified from the special reimbursement register (1999–2009). The study population included 8,195 women (227 cases of incident AD). RESULTS: Postmenopausal estrogen use was not associated with AD risk in register-based or self-reported data (hazard ratio/95% confidence interval 0.92/0.68–1.2, 0.99/0.75–1.3, respectively). Long-term self-reported postmenopausal HT was associated with reduced AD risk (0.53/0.31–0.91). Similar results were obtained with any dementia diagnosis in the hospital discharge register as an outcome. CONCLUSIONS: Our results do not provide strong evidence for a protective association between postmenopausal HT use and AD or dementia, although we observed a reduced AD risk among those with long-term self-reported HT use.