The age at which girls start their first menstrual cycle may impact their risk of heart disease, new research has found.
“It all started with the idea that we think the reproductive factors of women affect their health in different ways,” lead study author Dexter Canoy, a cardiovascular epidemiologist at Oxford University, told FoxNews.com.
Canoy, who works in the cancer epidemiology unit at Oxford, said that previous research suggested a link between the age of a woman’s first menstrual cycle and her cancer risk. But prior to his team’s latest study, published Monday in the American Heart Association’s (AHA) journal Circulation, no wide-range study had examined a potential association between a woman’s age at menarche— or first menstrual cycle— and vascular and heart disease risk.
In the new analysis, researchers analyzed data from about 1.3 million women in the United Kingdom. The participants, Caucasian women between the ages of 50 and 64, were recruited during routine breast cancer screenings between 1996 and 2001. The study participants’ average age was 55, and the group represented 25 percent of women in that age range in the U.K.
At the onset of their participation, the women were given a survey about their medical history, reproductive and sexual health. Then, researchers used data from the National Health Service Database to follow up on participant’s health information until 2011. Information from the database included hospitalizations or deaths from heart, cerebrovascular and hypertensive disease to determine the potential risk for these illnesses based on menarche age.
The data revealed that females who started their periods at age 13 had the lowest risk of developing these health issues, while those who started at age 10 or younger, and 17 or older, had the highest risk. The results illustrated a U-shaped trend, which indicated the older or younger a woman is, relative to age 13, the greater her risk of developing these problems. Among the earlier and later menarche groups, the risk of coronary heart disease (CHD) was higher than that of vascular and hypertensive disease. Women who had menarche at 10 or younger, or 17 or older, saw a 27 percent increased risk of heart disease, compared to women in the middle age range, researchers noted.
Because CHD is a leading cause of death worldwide, researchers didn’t think that disparity was surprising.
Most intriguing, Canoy said, was the idea that an earlier or later menarche increased the risk of all three illnesses taken into account: coronary heart, cerebrovascular and hypertensive disease.
Previous studies also suggest that only early menarche— but not both early and late menarche— may increase the risk of cancer, another finding Canoy said he found interesting.
In the current study, the trend even held true when researchers adjusted for other risk factors such as age, body mass index (BMI), smoking, alcohol consumption, use of hormonal birth control, exercise, and socioeconomic status.
“We thought that if there’s any excess risk, it would be explained by these factors,” Canoy said, “but it was quite robust. It was U-shaped throughout.”
AHA spokeswoman Donna K. Arnett, chair and professor of the epidemiology department at the University of Alabama at Birmingham, said the findings are important because they suggest a potential link between the growing obesity epidemic in western populations and an abnormal menarche.
“What was interesting in this paper is that the girls who did have earlier menstruation, less than 10 years of age, were heavier and did have other cardiovascular risk factors,” Arnett told FoxNews.com.
Those with the earliest and latest menarche had an average BMI of 28.1, which is considered overweight. These groups also were more likely to be treated for diabetes and hypertension compared to the women in the middle age range of the study’s findings.
Because the mean age of menarche is thought to be similar among western populations, Canoy said he thought the results would be comparable if the research had been conducted among a study group with the same characteristics in the U.S.
“If that’s true, women with earlier or later menarche may be able to adjust their lifestyles to control these health risk factors, researchers noted. For example, these high-risk groups may see benefits if they “lose weight if they’re overweight, control their blood pressure through diet or medications if necessary, and work to prevent diabetes through diet, weight loss and physical activity,” Arnett said.
Canoy said researchers are now coordinating with scientists in other areas of the world to analyze whether the same association exists in populations with a different mean menarche, like in Asia, where women tend to start their periods at a later age.
Arnett said further study could delve deeper into the potential causes of early or late menarche in women.
“What causes the early menarche, and is it a hormonal link to heart disease?” she said. “I don’t think we know that answer. Or is it the drivers that lead to early menarche, like being overweight, just really an early marker of heart disease, or is it hormonally linked, or both?”