Women who had their first menstrual cycle before the age of 13 may be at a higher risk of type 2 diabetes and stroke later in life.
Diabetes is rising among young and middle people in the United States, and it is estimated to affect one in three American adults by 2050 if the current trend continues.
At the same time, the age at which women start having periods is falling worldwide. In the U.S., it dropped from 12.1 in 1995 to 11.9 in 2013 and 2017.
To find the possible link between the two phenomena, researchers analyzed data from 17,377 women aged between 20 and 65 from the nationally representative National Health and Nutrition Examination Survey (NHANES) 1999–2018. The findings were published in the BMJ Nutrition Prevention & Health.
The women were categorized according to the age of their menarche — the medical term for the first menstrual cycle: 10 or younger, 11, 12, 13, 14, and 15 and older.
One in ten (1,773) women have been diagnosed with type 2 diabetes. And of those, 205 (11.5%) developed some cardiovascular disease.
Starting to have periods before the age of 13 was associated with an increased risk of type 2 diabetes after accounting for potentially influential factors, including family history of diabetes and weight.
Women who started menstruating at the age of 10 or younger were 32% more likely to develop diabetes. The first menstrual cycle at the age of 11 and 12 was associated with a 14% and 29% greater risk, respectively.
Earlier age at the first period was linked to an increased risk of stroke among women with diabetes but not cardiovascular disease in general.
The first menstruation at the age of 10 or younger was associated with a more than double stroke risk among women below the age of 65 with diabetes.
The risk of stroke fell with the increasing age of the first period: 81% among those who first menstruated at the age of 11, 32% at the age of 12, and 15% at the age of 14.
The study only shows an association, not a causal relationship, meaning that factors other than the first menstrual cycle may explain the increased incidence of diabetes. Because the age at the first menstruation was self-reported, women may not have recalled it correctly, potentially leading to classification errors.
However, the authors say that the earlier age at the first menstrual cycle "may be one of the early life indicators of the cardiometabolic disease trajectory in women."
They hypothesize that the increased risk can be explained by longer exposure to estrogen during life, as early menstruation has been linked to higher estrogen levels.
Higher risk of premature menopause
Previous studies have linked starting to have a menstrual cycle at an early age with an increased risk of breast cancer and early menopause before the age of 40.
A 2014 study found that women who had their first menstrual cycle at age 10 or younger were at a higher risk of heart disease, stroke, and complications of high blood pressure.
However, similar risks were observed in those who had their first period at 17 or older.
The study authors said that the cardiovascular risks could be reduced by tackling childhood obesity, which is linked to the lower age at the first menstrual cycle.
Other factors, such as genetics, increased subcutaneous fat, a high body mass index, and sugar-sweetened beverages, may also lower the age at which the first menstrual cycle occurs.
The new study does not prove that starting to menstruate at an early age causes diabetes later in life. However, genetics, being physically inactive, and being overweight are well-known risk factors for developing the condition.
- BMJ Nutrition Prevention & Health. Age at menarche, type 2 diabetes and cardiovascular disease complications in US women aged under 65 years: NHANES 1999–2018.
- EurekAlert. Young age at first menstrual cycle linked to heightened diabetes risk in mid-life.
- CDC. Number of Americans with Diabetes Projected to Double or Triple by 2050.
- National Library of Medicine. Early periods and late childbearing increase risk of breast cancer, study confirms.
- National Library of Medicine. Why should we be concerned about early menarche?
- Human Reproduction. Genome-wide association study meta-analysis of dizygotic twinning illuminates genetic regulation of female fecundity.
- Oxford Population Health. Women’s age at first menstrual cycle linked to heart disease risk.