Study: Having 5 or more babies may increase Alzheimer's risk by 70 percent

Women who have given birth to less than 3,500 women in South Korea and Greece.

Women who have given birth may be more likely to develop Alzheimer's in the United States and have fewer births, according to a new study of more than 3,500 women in South Korea and Greece.

may be more likely to develop Alzheimer's less than 3,500 women in South Korea and Greece.

The study looked at at women older than 60; The average age of women tested in both countries was 71.

The study also found that women who have experienced one or two pregnancies are much less likely to develop. In fact, women who had an interrupted pregnancy had almost half the risk.

"Based on previous research, we expected that the incidence of Alzheimer's disease," Dr. Ki Woong Kim, a study author neuropsychiatrist at Seoul National University, wrote in an email. "

Alzheimer's is a progressive mental deterioration of the brain that destroys memory and thinking skills until the end of the age. the person is unable to do even the simplest of tasks. Irreversible once it begins, the disease is thought to be caused by a buildup in the brain of beta amyloid plaques and neurofibrillary tangles called tau.

The 2016 World Alzheimer Report says more than 47 million people around the world are living with dementia, more than the population of Spain. In the United States alone, 5.5 million are currently living with Alzheimer's; 3.4 million of them are women. According to the Alzheimer's Association, women in their 60s are able to develop Alzheimer's disease.

Advancing age is the single greatest risk factor for Alzheimer's, and women typically live longer than men. But age is not the only factor. Studies show that women tend to have more amyloid plaques than men of the same age and mental status; other studies found that women with mild memory issues or who undergoes surgery with anesthesia decline faster than men. And a Stanford study found that women who carry the ApoE-4 gene, a genetic risk factor, are twice as likely to develop Alzheimer's ApoE-4. However, men carrying ApoE-4 have a slightly elevated risk.

What is it about women that can increase their odds of developing dementia? An obvious target for research has been hormones and the role of pregnancy.

"In animals, early pregnancy was badociated with cognition while late pregnancy and early postpartum with impaired cognition," Kim said. "In both animals and humans, estrogen is neuroprotective when it is modestly elevated while neurotoxic when extremely elevated."

Pregnancy is a hormonal roller coaster. During the first trimester, estrogen levels rise modestly, and then skyrocket for the rest of the pregnancy. By the third trimester, Kim said, estrogen levels can be "up to 40-fold higher" than their peak levels during natural menstrual cycles.

At the same time, levels of progesterone and a stress hormone called cortisol

According to Kim, those imbalances might be a factor in the uncommon results of his study.

"Because they are more likely to occur in the first trimester of pregnancy, it is possible that the modestly elevated levels of estrogen in the first trimester of pregnancy. Within the range of the risk of Alzheimer's disease, "he said.

But too many births may be the opposite, Kim said, by continually exposing women to dramatically elevated levels of estrogen and stress hormones, followed by thus reducing brain reserve.

"Washington, DC neurologist Dr. Pinky Agarwal, a fellow of the American Academy of Neurology. o was not involved in the study.

But this study, for example, is a study of high blood pressure, obesity, high cholesterol, and diabetes. cognitive reserve – socioeconomic status and employment. The study also excluded women who had used hormone replacement therapy, had a hysterectomy or had an ovary removed, which might also have a negative effect on the hormone levels.

However, she said,

Overall, Agarwal said, the study badyzed a possible contributory factor to the risk of Alzheimer's disease in that study.

James Hendrix, who direct the global science initiatives for the Alzheimer's Association, agrees with the need for more research. He feels that it is premature to suggest hormones are the main focus.

"There are other things that occur in hormone levels," he said. "Things like changes in the immune system, a healthy or poor diet, the level of exercise and just the stress of parenting.

The underlying reason is likely to be more likely to be multiple things, Hendrix said, and science needs a better understanding of what factors might be

"The takeaway for women is that we need more research to understand why," he said. "Women just do not wake up and have Alzheimer's. Brain health is a life course, and we need to understand how we are impacting our lives. "