Women's reproductive history not only has implications on our physical health, but also impacts the risk factors associated with dementia. New research presented at the Alzheimer’s Association International Conference 2018 in Chicago included the first-ever large-scale study of reproductive history and dementia risk in women and included some interesting findings.
Utilizing self-reported data from 14,595 women who were between the ages of 40 and 55, researchers found a correlation between risk of dementia and a number of reproductive health milestones, including the age of your first menstrual period, the number of children you've birthed, the number of miscarriages you've had, your age at natural menopause, and your overall reproductive period (the number of years between your first period and menopause).
“Possible causes of dementia in women, in particular reproductive factors, are not well understood,” Dr. Paola Gilsanz, a staff scientist at Kaiser Permanente Northern California Division of Research in Oakland, California, and one of the authors of the study, said in a statement. “In our study, we aimed to identify female-specific risks and protective factors impacting brain health, which is critical to diminishing the disproportionate burden of dementia experienced by women.”
Alzheimer's affects more women than men. Of the 5.5 million people age 65 or older with Alzheimer’s in the United States, 3.4 million are women according to the Alzheimer’s Association 2018 Alzheimer's Disease Facts and Figures. Up until now, the commonly accepted reason for this is that women tend to live longer than men and therefore would make up a larger percentage of the population affected by Alzheimer's.
The research reported at AAIC 2018 included some interesting findings. For example, women in the study with three or more children had a 12 percent lower risk of dementia than those with one child. In addition, with each reported miscarriage by the participants in the study, researchers found a 9 percent increased risk of dementia compared to those who did not report having any miscarriages.
The age a person gets their first period also appears to impact dementia risk. The study found that on average, women were 13 when they had their first menstrual period and were 47 when they reached natural menopause. Those who got their first period at a later stage — at age 16 or older — had a 31 percent greater risk for dementia than those who reported starting to menstruate at 13. Similarly, those who reached natural menopause at age 45 or younger had a 28 percent greater dementia risk, adjusting for demographics.
The research also found that the average length of a woman's reproductive period (the time between their first menstrual period and when they reach natural menopause) is 34 years. However, those who reported a shorter reproductive period — of 21 to 30 years — were 33 percent more likely to get dementia.
While this study is a good first step in getting a better grasp on why more women are affected by dementia than men, further work is required.
“More research is needed in this area, because having a better understanding of sex-specific risk factors across the lifespan may help us discover — and eventually apply — specific prevention strategies for different populations of people with Alzheimer’s and other dementias,” Dr. Maria Carrillo, chief science officer of the Alzheimer's Association, said in a statement.
If you'd like additional information on Alzheimer's and other types of dementia, please visit the Alzheimer's Association website or call their 24-hour hotline at 800-272-3900.