AGE THAT GIRLS HIT PUBERTY KEEPS DROPPING !!!!

[Daanyeer]

Source: http://news.cincinnati.com/article/2010 ... M1FC7Wk%3D

By Peggy O'Farrell • pofarrell@enquirer.com • August 9, 2010


The age at which girls hit puberty continues to drop, new research from Cincinnati Children's Hospital Medical Center shows.




Researchers led by Frank Biro, director of adolescent medicine at Cincinnati Children's, found that the number of 7- and 8-year-old girls with breast development was higher than found in studies conducted 10 to 30 years earlier.

Once breast development begins, menstruation typically follows within two to three years. Girls who menstruate earlier are at greater risk for breast cancer later in life.

Other health risks, including endometrial cancer, eating disorders and depression, are associated with earlier puberty and maturation. Behavioral issues, including earlier sexual activity, have also been noted.

"What causes earlier onset of puberty isn't entirely clear at this time, but we are looking closely at several different potential factors, including genes and environmental exposures, as well as how those two may interact with each other," Biro said.

The findings published today in Pediatrics include:

Among white girls, 10 percent of 7-year-olds had breast development, compared to 5 percent in a 1997 study. By age 8, 18 percent had breast development, compared to 10 percent found in a 1997 study.

Among black girls, 24 percent of 7-year-olds had breast development, while by age 8, 37 percent had breast development. The percentages were essentially the same as found in the 1997 study.

Researchers have found that race plays a role in puberty onset. Black girls tend to hit puberty younger than girls of other races and ethnicities. Heavier girls also hit puberty earlier, Biro said.

Biro's study is part of the ongoing "Growing Up Female" project at the University of Cincinnati, where he is on the faculty. It kicked off in 2003, and is following more than 1,200 girls from Cincinnati, East Harlem, N.Y., and the San Francisco Bay area.

Biro and his colleagues are focusing now on the role endocrine disruptors - chemicals that disrupt normal hormonal function - might play in earlier onset of puberty. Obesity is also believed to be a factor.

Endocrine disruptors are found in pesticides and herbicides, as well as in plastics, detergents and resins.

They enter the water or air during manufacturing or chemical processes, and build up in the fatty tissues in many animals.

For the study, girls are undergoing physical exams twice a year. Researchers are also collecting urine samples to analyze what chemicals and toxins they're being exposed to. They're also measuring hormone levels in the girls.

As the study goes on, researchers will "map out" all of that data and create a multilayered timeline linking age, chemical exposures and physical changes.

Researchers hope the data will help illustrate how puberty - and the events leading up to it, including environmental exposures - influences a woman's health over the rest of her life, said Susan Pinney, an environmental health researcher at UC and co-author of the study. She's also one of the investigators on the "Growing Up Female" project.

"Puberty is an extremely complex physical process," Pinney said. "This whole process is going to have an influence for the rest of her life."

Chemical exposures she experiences during childhood and adolescence may impact a woman's future children, for example, just as chemicals her mother was exposed to may have influenced her health.

A recent study showed women who gained weight during puberty had babies who were at higher risk of being obese, Pinney pointed out.

"I think the same kind of phenomenon may easily happen with environmental exposures," she said.

Researchers teamed up with breast cancer advocacy groups for the "Growing Up Female" project.

It's a unique angle to the project, Biro said.

And it's a unique opportunity for breast cancer survivors to learn how to reduce future generations' risk of developing the disease, said Ann Hernick, a Montgomery breast cancer survivor and president of the Breast Cancer Alliance of Greater Cincinnati.

"I became involved because I didn't want my daughter to face breast cancer, or, in the future, my granddaughter, if I'm lucky enough to have one," Hernick said.

"So many of us are involved in the project because we don't want to see future generations get this disease."