Women who experience poverty as a child or as an adult are more likely to start the menopause early, a study suggests.

Researchers in the United States have found that women who suffer economic hardship are 80% more likely to have early symptoms than those who have had no money worries.

They believe the stress associated with poverty may affect women's egg levels and cause them to lose fertility at a younger age.

Lauren Wise and colleagues at Boston University School of Public Health analysed the cases of over 600 women between the ages of 36 and 45.

The women, none of whom were menopausal at the beginning of the study, were monitored for three years.

The researchers also asked the women about their financial histories.

Early onset

Women who had suffered economic hardship in their early or later years were most likely to have early onset of the perimenopause.

This is the period leading up to the menopause, when the hormonal, biological and clinical changes begin.

Early signs include changes in the duration of or time between periods and changes in blood flow.

Those women who had lived through poverty experienced the perimenopause more than a year earlier than those who had never had money worries.

On average, they reported symptoms at the age of 44.

Writing in the Journal of Epidemiology and Community Health, the researchers said: "The study found that women reporting both childhood and adult economic distress had increased rates of entry into perimenopause compared with women reporting no economic distress across the lifecourse."

The link was still evident when the researchers took other factors such as smoking, bodyweight and depression into account. However, these reduced the overall risk.

They said more research was needed to identify why these women became menopausal early.

Other factors

However, they suggested that it was probably a combination of factors including stress and exposure to tobacco smoke and other toxins.

Dr John Stevenson, a reader in metabolic medicine at Imperial College London, said the findings were not particularly surprising.

"The findings confirm some earlier suggestions from other studies," he told BBC News Online.

Dr Stevenson suggested that early menopause was more likely to be linked with smoking, nutrition and body.

"Economically deprived people tend to have these," he said.