Study links early-maturing girls to risky behavior

As girls begin puberty at younger ages, physicians should be aware that early-maturing girls are more likely to engage in risk-taking behaviors such as sexual activity than their peers, says the author of a new study.

The study, published online Aug. 9 in Pediatrics, found that girls are more likely to start developing breasts at age 7 or 8 than were girls of the same age who were born more than a decade earlier.

"It's a little concerning, because we know that girls who develop early have significant social problems," said Warren Seigel, MD, chair of the Dept. of Pediatrics and director of adolescent medicine at Coney Island Hospital in Brooklyn, N.Y.

Women with a younger age of menarche also have an increased risk of breast cancer and endometrial cancer, according to the study (link).

Dr. Seigel recommends that pediatricians begin discussing sexual education with patients before they become teenagers. He said such discussions should be based on a patient's physical and cognitive development, as well as their age.

Researchers examined data on 1,239 girls in three metropolitan areas -- Cincinnati; East Harlem, N.Y.; and the San Francisco Bay. The girls were 6 to 8 when they enrolled in the ongoing study between 2004 and 2006.

At each site, health professionals assessed the participants' breast growth and pubic hair stages using criteria detailed in a June 1969 study in Archives of Disease in Childhood. Evaluations occurred annually at the health centers in California and New York. In Ohio, participants were seen every six months.

For breast development, the criteria range from Stage 1, when only the papilla is elevated above the level of the chest wall, to Stage 5, which indicates that mature breasts have developed.

Researchers found that at 7 years of age, 10.4% of white girls' breast maturation was at Stage 2 or greater. In Stage 2, the breasts may begin to elevate with some increased diameter of the areolae. Among Hispanic girls of the same age, 14.9% had breasts at Stage 2 or greater. For black girls, it was 23.4%.

The onset age of puberty was slightly later in a similar April 1997 Pediatrics study that examined girls 3 to 12 between July 1992 and September 1993. Researchers found that at 7 years of age, 5% of white girls' breast maturation was at Stage 2 or greater. Among black girls, the prevalence was 15.4%. There was no separate category for Hispanic girls.

Frank Biro, MD, lead author of the new Pediatrics study, recommends that physicians talk to patients and their parents about the importance of a healthy diet and regular exercise. A higher body mass index and inactivity can contribute to the early onset of puberty, said Dr. Biro, director of the Division of Adolescent Medicine at Cincinnati Children's Hospital Medical Center.

Other possible contributing factors include a person's genetics and exposure to certain chemicals in household and outdoor lawn products, he said.