Higher Dementia Risk in Women With Prolonged Fertility

A study published in Alzheimer's & Dementia determined that women with a longer reproductive period had an higher risk for dementia in old age, compared with those who were fertile for a shorter time, reports ScienceDaily . Researchers analyzed 1,364 women who were followed between 1968 and 2012 in the Prospective Population-based Study of Women in Gothenburg and the Gothenburg H70 Birth Cohort Studies in Sweden. Of those examined with a shorter reproductive period (32.6 years or less), 16 percent developed dementia. In the cohort of women who were fertile longer (38 years or more), 24 percent developed dementia. The risk for dementia and Alzheimer's disease was found to grow successively for every additional year that the women remain fertile. This association was most pronounced for those with dementia onset after 85 years, and the effect was most strongly connected to age at menopause. However, no association was observed between dementia risk and age at menarche, number of pregnancies, period of breastfeeding, or exogenous estrogen administered via hormonal replacement therapy or oral contraceptives. "The varying results for estrogen may be due to it having a protective effect early in life but being potentially harmful once the disease has begun," said University of Gothenburg Professor Ingmar Skoog.