Early ovary removal linked to elevated Alzheimer’s risk in women

Women who undergo early removal of both ovaries face a significantly higher risk of developing Alzheimer’s disease later in life, particularly if they carry the APOE4 gene variant, according to a recent study published in the Journal of Alzheimer’s Disease. The study, conducted by researchers at the University of Toronto in collaboration with the University of Alberta, sheds light on the critical role of hormonal and genetic factors in women’s brain health.

Analyzing data from 34,603 women in the UK Biobank, researchers found that those who had both ovaries surgically removed at an average age of 43 were four times more likely to develop Alzheimer’s than women who experienced natural menopause at around age 54. This elevated risk was particularly pronounced in women with the APOE4 allele, a well-known genetic risk factor for Alzheimer’s.

Dr. Gillian Einstein, a lead researcher, highlighted the combined impact of the APOE4 gene and the loss of estradiol, a naturally occurring hormone. “The interaction between APOE4 and the abrupt hormonal changes caused by ovary removal places these women at a heightened risk of Alzheimer’s, a situation we describe as double jeopardy,” Einstein stated.

Interestingly, the study also identified a modest but significant link between body mass index (BMI) and Alzheimer’s risk in women with early oophorectomy. Each additional unit of BMI correlated with a 7% reduction in Alzheimer’s risk. Researchers suggest that this could be due to estrone, a type of estrogen produced by adipose tissue, partially compensating for the loss of estradiol and potentially supporting cognitive function in middle age.

With Alzheimer’s projected to affect 12.7 million people aged 65 and older by 2050, two-thirds of whom will be women, this research underscores the need for tailored preventive strategies. Hormone replacement therapy (HRT) emerges as a critical intervention to mitigate cognitive decline risks for women undergoing ovary removal before age 50.

Dr. Noelia Calvo from the University of Toronto emphasized the findings’ clinical implications. “Estrogen-based therapies could be pivotal for women who undergo early oophorectomy, helping maintain brain health and reduce Alzheimer’s risks,” she said.

The study also raises questions about the gender disparity in Alzheimer’s prevalence, suggesting that early life hormonal events like oophorectomy may contribute. This research highlights the need for awareness and proactive measures to support women at risk.