The earlier a girl begins menstruating, the higher her risk of developing heart disease and cancer later in life, a new study suggests.
The research, published in the Journal of Clinical Endocrinology and Metabolism, found that women who had their first period before age 12 were 28 per cent more likely to die of cardiovascular disease and 25 per cent more likely to die of cancer than those who had their period later.
Women who had early menarche, the formal name for a girl's first menstrual period, also tended to have higher blood pressure, more heart disease and higher death rates overall once they reached middle age.
Dr. Rajalakshmi Lakshman of the Institute of Metabolic Science at Cambridge University in Cambridge, England, lead author of the study, said the connection between early menstruation and health problems later in life is not entirely clear.
What is known is that girls who are overweight or obese tend to menstruate earlier and that children who have weight problems often carry them into adulthood.
The new research, however, found a higher risk of illness and death for those who had early menarche regardless of their weight in adulthood.
Dr. Lakshman said one possibility is that excess weight in childhood and adolescence serves not only to trigger menstruation, but to "program" disease risk in some women, even if they are of healthy weight in their adult years. For this reason, she said, there needs to be greater awareness of the possible long-term health consequences of childhood obesity and that particular attention needs to be paid to girls who enter puberty at a young age.
Menarche can happen any time between 8 and 16. About 20 per cent of girls have their first period before age 12.
Exactly what triggers menstruation is not known, but it is widely believed to be related to critical weight - the name given to the ratio of fat to lean mass in a girl's body. Estrogen levels also play a role.
Menarche usually occurs within two years of the first signs of sexual maturation (breasts, pubic hair).
The new research involved 15,807 British women aged 40-79, who were followed between 1993 and 2007. During that period, researchers recorded 3,888 cardiovascular events (heart attacks, stroke, etc.) and 1,903 deaths.
Among the women who had early menarche, cardiovascular mortality was 28 per cent greater and cancer mortality 25 per cent more.
Earlier research has shown that breast cancer rates are significantly higher in women who began menstruating at a young age. That is because of greater exposure to estrogen.