A longer duration of estrogen exposure – extended by hormone therapy – is linked to better cognitive status in older adult women, a new study has found. 

The researchers followed 2,000 postmenopausal women for 12 years to examine the association between estrogen and cognitive decline. They calculated the duration of exposure to estrogen, accounting for factors such as time of menarche to menopause, number of pregnancies, duration of breastfeeding, and use of hormone therapy.

A longer period of estrogen exposure was associated with better cognitive status. And these beneficial effects were extended with hormone therapy, especially among the oldest participants, wrote JoAnn Tschanz, Ph.D., Utah State University, and colleagues. In fact, women who initiated hormone therapy earlier showed higher cognitive test scores than those who started taking hormones later.

The results may support a hypothesis that there’s an ideal window of time in which to begin post-menopausal hormone treatment, Tschanz concluded.

Many studies have suggested a role for estrogen in Alzheimer’s disease, which is disproportionately diagnosed in women. 

The findings were published Oct. 14 in the journal Menopause.