When did you get your first period? 10, 12, 15? New studies show that a girl’s first period, “menarche,” can have a significant impact on her physical and mental well-being throughout the rest of her life.
The age of menarche has a significant impact on physical health. Women that experience menarche earlier are more likely to get diabetes or cardiovascular disease. This is likely due to the estrogen associated with the arrival of menarche. Longer estrogen exposure can increase chances of developing breast cancer and ovarian cancer.
A 2002 meta-analysis, published in the journal Lancet Oncology and involving more than 400,000 women, showed that the chance of having breast cancer increases by five percent for every year younger the woman reached menarche.
Another study that was published in the journal Cancer Epidemiology, Biomarkers & Prevention, showed that girls that started their period before the age of 12 were less likely to survive ovarian cancer than those that reached menarche after 12.
The age of menarche also has a significant effect on mental health and has been linked to depression and eating disorders. Early menarche forces girls to physically grow up before they are mentally prepared to deal with their growing bodies. Girls will often look 15 or 16 years old and be treated as such when they are actually younger. Research has also shown that women that go through menarche earlier are more likely to achieve lower levels of education, and are more at risk for high-risk behaviors such as smoking, drinking, using drugs and having unprotected sex.
Why does all of this matter? Because the average age of menarche has been falling. In the mid 1800’s, the average age of menarche was 17 years old. By 2002, the age was 12.6 years and according the CDC, the age in 2010 was 12.5 years old. This is not only something that is seen in the United States. This can be seen in all countries across the world.
What explains this decline? Some scientists hypothesize that the decline is a result of chemicals from the environment and food that can cause hormonal changes. However, most scientists believe that fat is the culprit. In the mid 19th century, girls were often malnourished and had low body fat content. Lower body fat delayed puberty because menarche only started when the body was ready to rear a child. However, as more fat was introduced into diets in the 20th century, girls’ started showing signs of puberty at an earlier age.
However, starting in the 1950’s and 1960’s, the introduction of processed foods and microwaves contributed to a steep decrease in the average age of menarche. Girls were reaching menarche not because they had some fat, but because they had too much fat.
This can explain why girls from lower income families, many of whom are black and Latina, face a higher risk of reaching menarche early. In addition, girls from lower income families often have less access to spaces for exercise and healthier foods. In fact, a study published a few months ago in the American Journal of Medicine found a correlation between soda intake and early menarche.