Motherhood may affect Alzheimer's risk, studies show

Motherhood may affect a woman’s Alzheimer’s risk in unexpected ways, researchers reported Monday.

Women who had three or more children were less likely to develop dementia than women who had only one child, they found. And women who had miscarriages were more likely to develop dementia as well.

The researchers also found links between dementia risk and a woman's age at the onset of puberty or menopause.

The findings, presented at the annual Alzheimer’s Association conference in Chicago, might suggest that hormones affect a woman’s risk of developing the disease, said Heather Snyder, senior director of medical and scientific operations at the Alzheimer’s Association.

“It could be hormones,” Snyder told NBC News. Or it could have something to do with the immune system, which changes during pregnancy, or even the way a woman eats when she is pregnant.

“Or you can think about women with three children. They are multitasking a lot,” Snyder said. That could build up what are called brain reserves — extra reservoirs of brain function that have been shown to delay the symptoms of Alzheimer’s.

Paola Gilsanz of Kaiser Permanente in Oakland, California, and Rachel Whitmer at the University of California at Davis studied the cases of nearly 15,000 women ages 40 to 55 in the 1960s and 1970s.

Those who had three or more children were 12 percent less likely to develop dementia decades later, they found. The effect held even when Gilsanz and Whitmer took into account their weight and history of strokes, both of which affect dementia risk.

Miscarriages affected dementia risk also, they found. Every miscarriage a woman reported raised the risk of dementia by 9 percent.

In a separate study, a team that looked at 133 women in Britain found that those who spent more time being pregnant had a lower risk of Alzheimer’s than women who were otherwise very similar but spent less time being pregnant.

Full article: https://www.nbcnews.com/health/health-news/motherhood-may-affect-alzheimer-s-risk-studies-show-n893686

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