BCS70 helps uncover potential risk factors for early menopause

Information from women in the 1970 and 1958 cohort studies has been used to determine which aspects of women’s lives are linked to early menopause.

Menopause usually occurs between 45 and 55 years of age. If menopause begins before the age of 45, it is referred to as ‘early menopause’. Women with early menopause are often at higher risk of certain health problems, such as cardiovascular disease, osteoporosis, type 2 diabetes, and early cognitive decline.

The age a woman reaches the menopause is strongly influenced by her genes, but non-genetic factors can also play a role. It is important to understand what these non-genetic factors are, especially if they are things that can be changed to protect women’s health.

Somewhere between 5 to 10% of women will experience early menopause. By age 45, 6.5% of women in BCS70 and 10% of women in 1958 cohort had undergone natural menopause.

What we asked BCS70 women

Menopause is a natural part of women’s lifelong journey of reproductive health. As such, researchers suspect it can have roots as far back as infancy. They also think that certain risks can be more severe if they’re experienced at certain ages. Cohort studies like BCS70 are excellent resources to study the menopause because they collect information about their study members from birth through the whole of their lives.

This research drew on information we collected from your families when you were very young, such as how much you weighed when you were born, whether you were breastfed, whether your mothers smoked during pregnancy, and your father’s occupation. It also considered what you’ve told us about any health problems you’ve experienced over the years, how old you were when you got your first period, how often you smoke or drink alcohol, and what you’ve done for work as an adult.

When you reached your late 40s, we also asked you when you had your last period. Women who had not had a period in the past 12 months were considered menopausal, unless there was another reason menstruation has stopped, such as surgery, medication or pregnancy.

What the researchers found

Researchers from University College London found that several factors throughout women’s lives were linked to early menopause. Women whose fathers worked manual jobs were twice as likely as their peers to experience early menopause, compared to those whose fathers worked non-manual jobs. The chances were even higher for women whose fathers didn’t live with them when they were born.

Women had 30% higher odds of experiencing early menopause if they were breastfed for less than a month, and 24% higher odds if their mothers smoked while pregnant. Women’s own smoking habits were also linked to early menopause. Women who smoked at age 16 had 51% higher odds of early menopause, compared to those who did not smoke at this age. Women who smoked in their early 30s were 69% more likely to be early menopausal than their peers who didn’t smoke at this age.

Women who had suffered gynaecological problems by their early thirties were 68% more likely to be menopausal before 45 than their peers, and women who were unemployed in their late thirties or early forties were also more likely to undergo early menopause than those who were in work at these ages.

Encouragingly, getting one or more days of exercise per week in adulthood lowered the odds of early menopause, compared to exercising less frequently.

Other factors, such as birthweight, age at first period, adult body mass index, mental health problems, use of oral contraceptives, or not bearing children were not related to early menopause. The researchers also did not find a link between drinking habits at 16 and early menopause. In adulthood, women who drank alcohol one to three times per month were less likely to reach menopause before age 45 than those who drank less often, but the researchers noted that many people who drink less often do so because they have other health problems.

It’s important to remember that just because certain factors are linked to early menopause, does not necessarily mean they are causing it. For example, it’s possible that smoking has a direct effect on a woman’s fertility. However other factors, like socioeconomic circumstances, may affect things like diet and nutrition or emotional stress, which in turn may affect the age women reach the menopause.

Why these findings matter

Early menopause can lead to a number of serious medical problems, so understanding who tends to reach this milestone before the age of 45 is an important first step in protecting women’s health. By understanding who is at risk, researchers can start to investigate why this might be, and – crucially – what can be done about it.

Find out more about this research

The full research paper, ‘Risk factors for early natural menopause: evidence from the 1958 and 1970 British birth cohorts’ by Darina Peycheva and colleagues, was posted on medRxiv in September 2021.