New research presented at the American Heart Association’s Epidemiology, Prevention, Lifestyle & Cardiometabolic Health Conference 2022 has found women who experience very early menopause are significantly more likely to develop dementia in later life.

Women are known to be at a much higher risk of developing neurodegenerative diseases such as Alzheimer’s than men, but scientists have been unable to explain why this is the case. One hypothesis is that women simply live longer than men, so statistically they will present with more cases of dementia.

Some researchers have argued this explanation is overly simplistic and the real reasons behind the association are likely to be much more complex. More recently an idea has emerged scientists have dubbed the “estrogen hypothesis.”

The idea posits women appear to show a heightened susceptibility to Alzheimer’s because a drop in estrogen levels following menopause can exacerbate predispositions to the brain changes associated with neurodegenerative disease. Unfortunately, the solution is likely not as simple as using hormone replacement therapy to reduce dementia risk in post-menopausal women.

A key study published in 2003 found estrogen plus progestin therapy in menopausal women over the age of 65 actually increased a woman’s risk of dementia. So the relationship between estrogen and dementia is clearly very complicated.

The new research looked at UK Biobank health record data from more than 150,000 women. The goal was to look at the relationship between timing of menopause and later life dementia.

The findings revealed a strong correlation between early menopause and dementia. Women who entered menopause very early, before the age of 40, were 35 percent more likely to have a dementia diagnosis in later life. Menopause before the age of 45 was linked with higher rates of early-onset dementia before the age of 65.

“Our study found that women who enter menopause very early were at greater risk of developing dementia later in life,” said Wenting Hao, a researcher working on the study from Shandong University in China. “Being aware of this increased risk can help women practice strategies to prevent dementia and to work with their physicians to closely monitor their cognitive status as they age.”

Hao does allude to the estrogen hypothesis, suggesting it is possible the early life drop in hormone levels could speed up brain aging. But there is certainly too much discordant data at this stage to recommend menopausal women undergo hormone replacement therapy as a way of reducing dementia risk.

Instead, Hao recommends the findings be used by doctors and patients as a way of identifying those women at a higher risk of developing dementia. According to Hao, women reaching menopause before the age of 45 should engage in a number of behaviors known to reduce a person’s risk of cognitive decline.

“Dementia can be prevented, and there are a number of ways women who experience early menopause may be able to reduce their risk of dementia,” Hao explained. “This includes routine exercise, participation in leisure and educational activities, not smoking and not drinking alcohol, maintaining a healthy weight, getting enough vitamin D and, if recommended by their physician, possibly taking calcium supplements.”

Source: American Heart Association