UK Edition
Giving birth to more children raises risk of Alzheimer’s, study suggests
Women who have five or more children are at far greater risk of developing Alzheimer’s disease, new research suggests.
The study involving 3,549 women also found the risk of developing the neurodegenerative disease in later life is halved for women who have had an abortion or miscarriage.
The disease affects women more than men and researchers believe the findings may show a way of halting the condition early, by giving women hormone treatments.
Professor Ki Woong Kim, of the Department of Brain and Cognitive Sciences at Seoul National University College of Natural Sciences in Seoul, South Korea, said: "It's possible that the modestly raised levels of oestrogen in the first trimester of pregnancy are within the optimal range for protecting thinking skills.
"Oestrogen levels double by the eighth week of pregnancy before climbing to up to 40 times the normal peak level.
"If these results are confirmed in other populations, it is possible that these findings could lead to the development of hormone-based preventive strategies for Alzheimer's disease based on the hormonal changes in the first trimester of pregnancy."
Nearly two thirds of people living with dementia are women, but scientists do not understand why they are more affected.
For the study researchers looked at populations of women in Greece and Korea with an average age of 71, who were given a memory and thinking skills test, and asked them to provide information about their pregnancy history.
Of the 716 who had given birth to five or more children 59 developed the disease, 70 per cent higher than the those with fewer children.
The women who had five children or more also scored an average of 22 points - four fewer than the average of the other women.
However, of the 2,375 women who had an abortion or miscarriage, only 47 developed the disease - and scored more than 23 points on the tests on average.
Dr Doug Brown, Chief Policy and Research Officer at Alzheimer's Society, said: "We know women are more at risk of developing dementia than men but we don't yet know why - and as it's the only one of the top ten killers we can't treat or cure, research like this is vital to better understand what causes dementia and how we might be able to reduce that risk.
"This research shouldn't give women who've given birth several times any cause for concern; it does highlight interesting links between changing hormone levels and dementia risk, but there are still too many unanswered questions.”
Dr Carol Routledge, Director of Research of Alzheimer’s Research UK, added: “Pregnancy is a complex biological process which involves changes in the levels of several hormones including the female sex hormone oestrogen.
“This study lends support to the idea that oestrogen or other hormones may have an impact on Alzheimer’s risk, but we don’t understand the nature of this relationship.”
The paper was published in the American Academy of Neurology and online journal Neuorology.