Women who experienced miscarriage and those with early and late menarche had an elevated dementia risk, according to a presentation at the Alzheimer’s Association International Conference.
“Possible causes of dementia in women, in particular reproductive factors, are not well understood,” Paola Gilsanz, ScD, from Kaiser Permanente Northern California Division of Research, said in a press release. “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.”
Gilsanz and Rachel Whitmer, PhD, from the University of California, Davis, enrolled 14,595 women who were aged between 40 and 55 years during 1964 to 1973.
During that time, participants reported number of children, miscarriages and age of menarche and menopause, as well as their education, race, sex and midlife health indicators, including BMI, hypertension and smoking. Then, from 1996 to 2017, the researchers used data from medical records to determine participants’ dementia diagnoses and late-life health indicators, including stroke, heart failure and diabetes.
The analysis indicated that the risk for dementia was 12% lower among women with three or more children compared with those with one child. Women with more children continued to have a lower risk for dementia even after adjusting for mid- and late-life risk factors.
Dementia risk increased 8% with each additional report of a miscarriage (adjusted HR = 1.08; 95% CI, 1.05-1.12). Women with three or more miscarriages had 47% increased risk for dementia compared with those with no miscarriages (aHR = 1.47; 95% CI, 1.27-1.71).
Menarche at both older and younger ages was associated with greater risk for dementia compared with menarche between ages 10 and 13 years, with a 22% increased risk among those who started their first menstrual period at age 16 years or older (aHR = 1.22; 95% CI, 1.03-1.44) and a nonsignificant 40% increased risk among those who started their first menstrual period at age 9 years or younger.
Age of menopause and dementia risk did not appear to be associated.
Another study presented at the conference was led by Molly Fox, PhD, from the University of California, Los Angeles, and demonstrated that among 133 elderly British women, there was a 5.5% decrease in Alzheimer’s risk for each additional month of cumulative pregnancy.
“We are intrigued by the possibility that pregnancy may reorganize the mother’s body in ways that could protect her against developing Alzheimer’s later in life,” Fox said in a press release. “These results also suggest that the story might not be so simple as being all about estrogen exposure, as previous researchers have suggested.” – by Alaina Tedesco
Fox M. Women’s pregnancy history may influence Alzheimer’s risk through alterations in immune function. Presented at: Alzheimer’s Association International Conference; July 22-26; Chicago.
Gilsanz P, Whitmer R. Women’s reproductive history and dementia risk. Presented at: Alzheimer’s Association International Conference; July 22-26; Chicago.
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