Early puberty in girls troubling; Phenomenon raises risk of breast cancer and emotional problems
DORSEY GRIFFITH
McClatchy Newspapers
16 September 2007
Charlotte Observer (NC)
Copyright 2007 The Charlotte Observer. All rights reserved.
SACRAMENTO, Calif.
American girls are entering puberty at earlier ages, putting them at far greater risk for breast cancer later in life and for all sorts of social and emotional problems well before they reach adulthood.
Girls as young as 8 increasingly are starting to menstruate, develop breasts, and grow pubic and underarm hair -- biological milestones that only decades ago typically occurred at 13 or older. African American girls are especially prone to early puberty.
Theories abound as to what is driving the trend, but the exact cause, or causes, are not known. A new report, commissioned by the San Francisco-based Breast Cancer Fund, has gathered heretofore disparate pieces of evidence to help explain the phenomenon -- and spur efforts to help prevent it.
"This is a review of what we know -- it's absolutely superb," said Dr. Marion Kavanaugh-Lynch, an oncologist and director of the California Breast Cancer Research Program in Oakland, which directs tobacco tax proceeds to research projects. "Having something like this document put together that discusses all the factors that influence puberty will advance the science and allow us to think creatively about new areas of study."
The stakes are high: "The data indicates that if you get your first period before age 12, your risk of breast cancer is 50 percent higher than if you get it at age 16," said the report's author, biologist Sandra Steingraber, herself a cancer survivor. "For every year we could delay a girl's first menstrual period, we could prevent thousands of breast cancers."
Kavanaugh-Lynch said most breast cancer cells thrive on estrogen, and girls who menstruate early are exposed to more estrogen.
Steingraber's paper, "The Falling Age of Puberty in U.S. Girls: What We Know, What We Need to Know," examines such things as obesity, inactivity, family stress, media imagery and accidental exposures of girls to chemicals that can change the timing of sexual maturation.
Steingraber concludes that early puberty could best be understood as an "ecological disorder," resulting from a variety of environmental hits.
"The evidence suggests that children's hormonal systems are being altered by various stimuli, and that early puberty is the coincidental, non-adaptive outcome," she writes.