7 surprising things your first period can tell you about your health

Do you remember when you got your first period? If not, think harder because your doctor may soon be asking. In the last year, research has linked the age of first menstruation to health risks ranging from allergies and heart disease, to diabetes and cancer.

Scientists don't yet know the exact connection, but it may involve your weight at the time your period arrived. "Estrogen is tied to fat," says Taraneh Shirazian, M.D., a gynecologist at The Mount Sinai Hospital in New York. So if you began menstruating at a young age, this could be a clue that you reached your "normal" adult weight early, thereby setting yourself up for obesity and all its related health woes later.

Or it might just be genetics at work. "Women who have earlier first periods may have some factors that predispose them to disease," explains Shirazian. Until we know for sure, here's what the arrival of your menses might divulge about your health risks.

HEART DISEASE

According to a new study involving 1.3 million women published in the journal Circulation, those who started menstruating at age 13 had the lowest risk for heart disease, stroke and high blood pressure. Conversely, those who began at age 10 or younger (or 17 and older) had the highest risk, specifically 27 percent more for heart disease, 20 percent for high blood pressure, and 16 percent for stroke.

TYPE 2 DIABETES

Women who got their first period before age 12 have a significantly greater risk of type 2 diabetes than those who got it later in life, according to a survey of about 4,600 middle-aged women published in Diabetic Medicine. "The early menarche increased diabetes by increasing insulin resistance," says study author Jung Sub Lim, M.D., Ph.D.

PREECLAMPSIA

This condition is marked by high blood pressure and protein in the urine during pregnancy. It then becomes a risk factor for stroke afterward. If your first period arrived before age 12, your odds of developing this life threatening condition while pregnant is about 28 percent greater than if menstruation started at age 13 or later, according to a study in the Journal of Clinical & Diagnostic Research.

THYROID CANCER

In a study published in the American Journal of Epidemiology, French researchers interviewed about 600 young women who were diagnosed with thyroid cancer before age 35, in addition to about 600 healthy women. Those with an early first period had a higher risk of the disease.

BRAIN TUMOR

Chinese researchers examined many different reproductive factors and how they contribute to brain tumor risk. One of their most striking findings was that women who didn't start menstruating until age 17 or later had an elevated risk of developing brain tumors.

BONE DENSITY

Surveys of pre- and post-menopausal women reveal that a first period arriving at age 17 or older correlates with lower bone mineral mass and a higher risk of fracture from osteoporosis.

ALLERGIES

Researchers have found a link between early puberty (10 years old and under) and eczema, asthma, and rhinoconjunctivitis, especially among African-Americans and Hispanics. But so far it hasn't been determined whether it's early puberty that triggers these allergies, or vice versa.

If the arrival of your first period puts you at risk for one or more of these conditions, don't make the mistake of thinking your health is pre-determined. Lim and Shirazian both point out that a healthy lifestyle (being active, controlling weight, watching what you eat) can go a long way toward offsetting the risk.