Fertility isn’t something older Australians give much thought to, but if you are worried about developing dementia, it might be something you need to look back on.
New research has discovered a link between how long women are fertile for in their younger years and the risk of developing dementia in old age.
According to the University of Gothenburg research, women with a longer reproductive period had a higher risk of developing dementia than those women with a shorter reproductive period.
Dr Jenna Najar said the results could help explain why women have a higher risk of developing dementia and Alzheimer’s disease than men after age 85.
She said the results also supported the idea that oestrogen affects the risk of dementia among women.
The study, which involved 1364 women, considered the reproduction period to start at the onset of menstruation and finish with menopause.
Of the women who had a reproductive period of 32.6 years or less, 16 per cent developed dementia. Of the women who were fertile for 38 years or more, 24 per cent developed dementia.
The risk for dementia and Alzheimer’s increases for every additional year that the woman remains fertile, according to the results of the study.
Cases where the onset of dementia was over the age of 85 had the strongest association with the link to long reproductive periods.
The effect was also more strongly related to those who started menopause late, rather than those who started menstruating early.
The researchers did not find any association between dementia and the number of pregnancies that a woman, duration of breastfeeding or hormone replacement therapy.
Several studies have investigated how oestrogen in the form of HRT affects dementia risk. Some studies show that dementia risk falls and others that it rises, especially in women who take oestrogen late in life.
“What’s novel about this study, too, is that we’ve had access to information about several events in a woman’s life that can affect her oestrogen levels,” Dr Najar said.
“Examples are pregnancies, births and breastfeeding. Being pregnant boosts oestrogen levels tremendously; then they decline once the baby is born, and if women breastfeed the levels fall to extremely low levels. The more indicators we capture, the more reliable our results are.”
Professor Ingmar Skoog, who led the study, explained that the duration of a woman’s fertile period was just one risk factor for dementia among many.
“The varying results for oestrogen may be due to it having a protective effect early in life but being potentially harmful once the disease has begun,” he said.
Most women whose menopause is delayed do not develop dementia because of this factor alone. However, the study may provide a clue as to why women are at higher risk than men for dementia after age 85.
At what age did you start experiencing menopause? Were you fertile for 38 years or more? Are you worried you are at greater risk of developing dementia?
If you enjoy our content, don’t keep it to yourself. Share our free eNews with your friends and encourage them to sign up.