The study, published in the June issue of the Journal of Pediatrics, was conducted as part of the National Heart, Lung and Blood Institute (NHLBI) Growth and Health Study. In the study, which followed more than 850 young girls over a period of 10 years, Frank Biro, MD, a physician at Cincinnati Children's, discovered that girls whose onset of puberty is marked by breast development are more likely to be obese by late adolescence than young girls whose first sign of puberty is pubic hair.
The study discovered that onset of puberty marked by breast development not only increases the risk of obesity but also "may serve as a risk marker for breast cancer," according to Dr. Biro, a physician in the division of Adolescent Medicine at Cincinnati Children's and the study's lead author.
"Girls whose initial manifestation of puberty is breast development had greater body mass and body fat one year before puberty as well as throughout puberty," says Dr. Biro. "In addition, epidemiological studies have noted a greater risk of breast cancer in those women who reported an earlier age of menarche (first menstruation). There is also an association between breast cancer, earlier age of menarche, and greater body mass index and body fat. Since girls who enter puberty with breast development have an earlier age of menarche, and greater BMI and body fat, this pathway beginning with breast development may serve as a risk factor for breast cancer."
Supporting Dr. Biro's suggestion of an increased risk of breast cancer is a study of twins published in the June 5, 2003 issue of The New England Journal of Medicine. In this study, researchers discovered that earlier age of breast development is associated with earlier age of diagnosis of breast cancer.
The study involved 859 white girls, who were 9 or 10 years old at the beginning of the study. They were followed with annual visits for 10 years. Physical examinations included height, weight, skinfold thicknesses and pubertal maturation assessment. Black participants were not able to be included in the study, because many had already initiated pubertal maturation at the age of intake into the study.
"Appoximately two of every three girls enter puberty with breast development preceding the development of pubic hair," says Dr. Biro. This study indicates that health care providers and families need to be more aware of the risks."
The study was funded by the NHLBI, a division of the National Institutes of Health. The Growth and Health Study is a longitudinal study that has examined for many years the impact of growth and development on cardiovascular risk factors among black and white adolescent girls.
Cincinnati Children's Hospital Medical Center is a 373-bed institution dedicated to the pursuit of perfect health care. It is the only pediatric organization in the United States to receive the prestigious Pursuing Perfection grant from the Robert Wood Johnson Foundation. The Cincinnati Children's Research Foundation ranks third nationally among all pediatric centers in research grants from the National Institutes of Health. The Cincinnati Children's vision is to be the leader in improving child health, through patient care, research and education. Additional information about Cincinnati Children's can be found at www.cincinnatichildrens.org.
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Journal
The Journal of Pediatrics