Low weight linked to risk of early menopause, study finds

In France, an estimated 30,000 to 40,000 people -- almost all of them adolescents -- suffer from anorexia nervosa. (sniegirova mariia/shutterstock.com)

Underweight women, or women who were underweight when they were young, are at greater risk of experiencing early menopause, according to a new study.

According to the new research, entering menopause at an early age -- before age 45 compared to around 50, on average -- could be linked to being underweight or to weight fluctuations from age 18, among other things.

Researchers studied 78,759 women aged 25 to 42 between 1989 and 2011, recording their body mass index (BMI), weight distribution, weight change during that period and age of menopause. Medical history, smoking and exercise were also recorded at the time of joining the study, then updated by means of questionnaires every two years thereafter.

During the period of study, 2,804 women reported early menopause, according to the authors.

The study found that the women who were underweight at any age -- with BMI under 18.5 kg/m2 -- had a 30 per cent increased risk of early menopause compared to slim or normal weight women (BMI of 18.5 to 22.4 kg/m2).

This rose to 50 per cent for women who were underweight at age 18 (BMI less than 17.5 kg/m2). At age 35, underweight women with a BMI under 18.5 kg/m2 had a 59 per cent increased risk of early menopause.

Being overweight appeared to lower the risk: women with a BMI between 25 and 29.9 kg/m2 had a 21-30 per cent lower risk of early menopause than normal weight women.

The researchers note that women who reported losing around 10 kg or more three times between the ages of 18 and 30 had a 2.4-fold increased risk of early menopause. However, this was reported by only seven women.

Around 10 per cent of women experience early menopause. Experiencing this hormonal change earlier in life is associated with elevated risk of cardiovascular disease, cognitive decline, osteoporosis and early death. Underweight women may, therefore, want to raise the issue of potential implications with their doctor, suggest the authors.

The study is published in the journal Human Reproduction.