According to preliminary research presented at the American Heart Association's Epidemiology, Prevention, Lifestyle & Cardiometabolic Health Conference 2022, women who enter menopause very early, before age 40, are more likely to develop dementia of any type later in life than women who begin menopause at the average menopause-onset age of 50 to 51 years. The summit took place in person in Chicago and digitally from Tuesday, March 1 to Friday, March 4, 2022, and featured the most up-to-date population-based knowledge on cardiovascular health promotion and stroke prevention.
Dementia is a brain disease that impairs a person's capacity to recall, make decisions, and communicate. The most common type of dementia is Alzheimer's disease, followed by vascular dementia, which is caused by disturbances in blood flow to brain cells caused by strokes or plaque build-up in arteries providing blood to the brain. Both of these types of dementia become increasingly common as people get older. Dementia can also be caused by diseases that damage specific areas of the brain, and a person can develop dementia as a result of more than one disease process.
The current study looked into the possible link between the age at which menopause begins and the diagnosis of dementia from any cause. The health records of 153,291 women with an average age of 60 when they joined the UK Biobank (between 2006 and 2010) were analysed. The UK Biobank is a big biological database that contains genetic and health information on half a million people in the UK.
The researchers were able to distinguish between Alzheimer's disease, vascular dementia, and dementia caused by other factors. They compared the women who started menopause at the typical age of menopause onset, which is 50-51 years, to the women who started menopause at the average age of menopause onset, which is 50-51 years (51 years is the average age for menopause onset among women in the U.S.). Age at last exam, race, educational level, cigarette and alcohol usage, BMI, cardiovascular disease, diabetes, income, and leisure and physical activities were all taken into account.
The analysis found:
• Women who went through menopause before the age of 40 had a 35 per cent higher chance of being diagnosed with dementia.
• Women who went through menopause before the age of 45 had a 1.3 times higher chance of being diagnosed with dementia before the age of 65. (called presenile or early-onset dementia)
• Women who started menopause at the typical age of menopause onset, which is 50-51 years old, had similar rates of dementia as women who started menopause at the average age of menopause onset, which is 52 years old
Despite the fact that post-menopausal women have a higher risk of stroke than pre-menopausal women, and that stroke can impair blood flow to the brain and lead to vascular dementia, the researchers found no link between age at menopause and the risk of vascular dementia in this study.
"Dementia can be prevented, and there are a number of ways women who experience early menopause may be able to reduce their risk of dementia. This includes routine exercise, participation in leisure and educational activities, not smoking and not drinking alcohol, maintaining a healthy weight, getting enough vitamin D and, if recommended by their physician, possibly taking calcium supplements," said Wenting Hao, MD, PhD candidate at Shandong University in Jinan, China.
Lower estrogen levels, according to the researchers, could be a component in the possible link between early menopause and dementia.
"We know that the lack of estrogen over the long term enhances oxidative stress, which may increase brain ageing and lead to cognitive impairment," Hao said.
Women's health care doctors should be aware of a woman's age at menopause onset and keep a close eye on those who experience menopause before the age of 45 for signs of cognitive deterioration.
"Further research is needed to assess the added value of including the timing of menopause as a predictor in existing dementia models," Hao said. "This may provide clinicians with a more accurate way to assess a woman's risk for dementia."
The study includes a number of flaws. Women's self-reported information about their age at menopause start was used by the researchers. Furthermore, the researchers did not distinguish dementia rates in women who had a naturally occurring early menopause from women who had menopause induced by ovaries removal surgery, which could have influenced the findings. The data used in this study came from predominantly white women in the United Kingdom and may not apply to other populations.