Conversely, the factors associated with a decreased risk were ever having been pregnant, ever having had an abortion, longer reproductive lifespan and later menopause.
“With regard to external hormones, the use oral contraceptive pills was associated with a lower risk of dementia, but our study findings did not support an association between HRT and dementia risk,” Ms Gong said.
The authors proposed that risk variation in women may not be associated with childbearing because a similar pattern was observed between number of children fathered and dementia risk among a similar number men in the same study.
“We found that the higher dementia risk linked to early (natural and artificial) menopause was more pronounced in women of lower socioeconomic status,” she added.
“Social deprivation is likely to be an important determinant of dementia risk as well as other aspects of women’s health.”
With dementia on the rise and in the absence of significant treatment breakthroughs, the focus has been on reducing the risk of developing the disease.
“More research is needed to understand whether these differences are associated with life-long exposure to the body’s own estrogen, and whether external hormone use could influence the risk of developing dementia,” added Ms Gong.
“Our findings may be helpful for identifying high-risk women to participate in future clinical trials to assess potential preventive measures and treatments.”