Prolonged oestrogen exposure in older women yields cognitive benefits

Older women with longer endogenous oestrogen exposure and hormone therapy use are at much higher odds of having favourable cognitive status in late life, a recent study suggests.

Researchers looked at 2,114 dementia-free women (mean age, 74.94 years) at baseline who were enrolled in a 12-year population-based study in Cache County, Utah, US. All women completed a women's health questionnaire, which detailed reproductive history and hormone therapy use. They also underwent cognitive status assessment using a modified version of the Mini-Mental State Examination (3MS) at four triennial waves.

Researchers calculated endogenous oestrogen exposure by taking the reproductive window (age at menarche to age at menopause) and adjusting for pregnancy and breastfeeding. Hormone therapy variables included duration of use, type (unopposed and opposed) and time of initiation.

There was a positive association between endogenous oestrogen exposure and cognitive status (p=0.054). The same was true for longer duration of hormone therapy use (p=0.046), but exerting a major impact on age, such that older women obtained greater benefit compared with their younger counterparts.

The timing of hormone therapy initiation showed a significant association with 3MS (p=0.048). Specifically, higher 3MS scores were observed in women who initiated therapy within 5 years of menopause than in those initiating therapy ≥6 years later.

Possessing potent antioxidant properties, oestrogens play important roles in maintaining normal reproductive and nonreproductive functions. These hormones exert neuroprotective actions and their loss during ageing, and their loss has been suggested to promote an accelerated ageing phenotype eventually leading to the development of brain hypometabolism, a feature commonly observed in menopausal women and prodromal Alzheimer’s disease. [Front Aging Neurosci 2017;9:430]