Starting Your Period Before Age 13 Could Raise Your Risk of Type 2 Diabetes

Girls who started their period before age 13 were more likely to develop type 2 diabetes later in their adult years, according to a new study published on December 5 in BMJ Nutrition Prevention and Health.

In the women who developed diabetes, there was also an association found between early menstruation and having a stroke before age 65, especially in those who started their monthly cycles at age 10 or younger.

Based on these findings, women who started their periods at a very early age might be at higher risk for developing diabetes and diabetes complications in early adulthood and midlife, says coauthor Sylvia Ley, PhD, RD, an assistant professor at Tulane University School of Public Health and Tropical Medicine in New Orleans.

“These high-risk women may consider watching out for other early-onset metabolic risk factor changes, such as blood sugar levels, lipid profile [cholesterol and triglycerides], and blood pressure in early and middle adulthood,” says Dr. Ley.

The findings are thought provoking and the risks identified here should be the basis for further research, says Yalda Afshar, MD, PhD, an assistant professor-in-residence of obstetrics and gynecology in the division of maternal and fetal medicine at UCLA Health in Los Angeles.

It’s important to note that because of the way the study is designed, the link found here is an association — it hasn’t been proven that starting your period at an earlier age directly causes the increased risks for type 2 diabetes or stroke, says Dr. Afshar, who was not involved in the study.

But the findings do align with many other earlier studies which suggest that reproductive factors — such as the age you start your period or go through menopause — affect your long-term cardiometabolic health, she says.

When Do Most Girls Have Their First Period?

The first menstrual period, called menarche, typically occurs between the ages of 10 and 16, with the average age in the United States being 11.9 years old, according to a report published in September 2020 by the Centers for Disease Control and Prevention.

However, girls are also starting their periods earlier: The number of adolescents who started their first period by age 10 is on the rise, going from 7 percent of girls in 1995, to 10 percent in 2013 through 2017, according to the same report.

It isn’t clear why more girls are getting their first period earlier. It could be related to increasing body fat, as well as family income, genetics, general health, diet quality, exercise, seasonality, and even family size.

Study Among the First to Include a More Diverse Population of Women

Ley cites the younger age of first periods — along with the rise of diabetes and diabetes complications in U.S. adults under 65 years old — as the reasons for the study. “Age at menarche has been associated with higher risk of diabetes and with cardiovascular disease (CVD) independently, but it remains unclear whether age at menarche is a risk factor for CVD complications among younger women with diabetes,” she says.

Researchers analyzed data from about 17,000 women ages 20 to 65 years. As part of the National Health and Nutrition Examination Survey (NHANES) from 1999 to 2018, participants reported their age at first menstruation. Of the participants, 19 percent were Hispanic, 55 percent white, 20 percent Black, and 6 percent other races.

The relative diversity of the study is important: Most of the existing studies looking at earlier age at menstruation, type 2 diabetes, heart disease complications were primarily in white American and European populations, according to the authors.

Higher Risks Found in Women Who Had Their First Period Very Early

In total, 10.2 percent of the women had type 2 diabetes, and of these, 11.5 percent had cardiovascular disease, defined as coronary heart disease, heart attack, or stroke.

Compared with women who had their first menstrual period at age 13, those who had their first period at:

• 10 years or younger had a 32 percent increased risk of type 2 diabetes.
• 11 years had a 14 percent higher risk for type 2 diabetes.
• 12 years had a 29 percent higher risk for type 2 diabetes.

The findings were adjusted for age, race and ethnicity, education, income, menopause status, family history of diabetes, smoking status, physical activity, alcohol consumption, and body mass index (BMI).

Among the women with diabetes, compared with those who had their first menstrual period at age 13, those who had it at age 10 or younger had more than double (166 percent) the risk of having a stroke — but not coronary heart disease or cardiovascular disease in general, after adjusting for those multiple variables.

Similarly, among women with diabetes, compared with those who had their first period at age 13, the increased risk for stroke was:

• 81 percent higher for those with their first period at age 11
• 32 percent higher for those with their first period at age 12
• 15 percent higher for those with their first period at age 14

The authors acknowledged that as an observational study, it isn’t proven that early first period causes the increased risks, but the findings suggest that “earlier age at [first menstrual cycle] may be one of early life indicators of the cardiometabolic disease trajectory in women.”

Findings Highlight the Need for Heart Disease Risk Studies in Ethnically Diverse Groups of Women

“These findings add another dimension to the potentially less well understood determinants of cardiometabolic risk, particularly in women who have been relatively underrepresented in this area of research,” said Sumantra Ray, PhD, executive director of the NNEdPro Global Centre for Nutrition and Health in Cambridge, England, in a press release.

“And they provide a clear steer on the need to design interventional studies looking at the prevention of cardiometabolic disease in ethnically diverse groups of women who start menstruating at a young age,” said Dr. Ray.

Identifying modifiable and nonmodifiable risk factors for diseases such as type 2 diabetes and heart disease can help doctors and public health officials optimize interventions and keep people healthier, says Afshar.

How Could the Age That You Start Your Period Influence T2D or Stroke Risk?

If there is a link, one potential explanation is that these women are exposed to estrogen for longer periods of time, and early periods have been associated with higher estrogen levels, they wrote.

Being overweight or obese may also play a role. The associations between age at first menstrual cycle and stroke complications weakened slightly after accounting for weight, though they still remained statistically significant, the authors wrote. This suggests that body fat may play a role, given that higher childhood levels of overweight and obesity are associated with earlier age at menstruation and with cardiometabolic diseases later in life, they suggested.

Expert Advice For Women Who May Be at Higher Risk

Women who started their periods early — especially at age 10 or younger — may want to proactively discuss metabolic risk factors with their provider and watch out for changes in blood sugar, cholesterol, and triglyceride levels, and in blood pressure during early and middle adulthood, says Ley.

Afshar hopes that studies like this one will remove stigmas around talking about periods. “I hope that the findings become an impetus for reproductive-age people to discuss their menstrual histories with their physicians, early and openly,” she says.