Pregnancy Bliss | Reproductive Health Answers
Published: Sunday, March 20, 2011 - 15:55
A Danish study involving over 3000 Danish girls has revealed that obesity in childhood is fueling increased levels of earlier menarche. It's nothing new that age at menarche has been falling and results of this study appear to confirm what experts have warned about for some time that the current obesity epidemic may be largely responsible for the trend. The study results appear in the March 10, 2011 online edition of the Journal Fertility and Sterility®.
Early-onset menstruation is linke d to later health problems such as breast cancer, said Dr. Sarah Keim, a researcher at The Ohio State University College of Medicine in Columbus who wasn't involved in the new study.
Girls who start menstruating earlier are also more likely to have sex before most of their peers do, Dr. Keim added, which increases the risk of teen pregnancy, cervical cancer and sexually transmitted diseases.
These results come only a few months after results of an earlier study carried out by researchers at the Medical university of South Carolina showing that overweight girls are more likely to start having sex early, to have multiple partners during their teen years, and to eschew condoms compared to thinner teens.
1 in 6 are obese
About 17% of American kids and teens are obese, according to the Center for Disease Control and Prevention. For the study, researchers analyzed information on body mass index (BMI) and age at first period from about 3,200 Danish girls born between 1984 and 1987.
On average, the girls had their first periods just after turning 13, which is about half a year later than in the U.S. Dr. Keim said part of the reason for this difference may be that African-Americans tend to start their periods before white girls.
On average, menarche came 25 days earlier for every point of BMI above average. Overweight and obese girls, for example, got their period three to five months before normal-weight girls, said Anshu Shrestha, a graduate student at the University of California, Los Angeles School of Public Health who worked on the study.
Past research has shown a link between BMI and the onset of menstruation. Since this study is recent, it shows the link persists in today's generation, Dr. Keim said.
The mother too
The researchers also found that a girl's mother's weight was related to when her daughter started menstruating, but less so than earlier work had hinted. For every point her mother's pre-pregnancy BMI went up, the girl's period came about a week earlier.