Breast Cancer Fund Examines Causes, Effects Of Early Puberty
A variety of environmental factors could be responsible for earlypuberty among girls in the U.S., according to a recently releasedreport commissioned by the San Francisco-based Breast Cancer Fund, the Sacramento Bee reports. According to the Bee,U.S. girls as young as age eight are beginning to menstruate, developbreasts, and grow pubic and underarm hair, all of which a few decadesago typically occurred at age 13 or older. Black girls are more likelythan other girls to begin puberty at an early age.
The report-- titled "The Falling Age of Puberty in U.S. Girls: What We Know, WhatWe Need To Know" and written by biologist Sandra Steingraber --examined factors such as obesity, family stress, inactivity, sexualimagery in the media and accidental exposure to chemicals that mightprompt early puberty. The report concluded that early puberty can bebest described as an "ecological disorder" resulting from differentenvironmental factors.
According to Steingraber, risingchildhood obesity has contributed to early puberty because puberty istriggered by leptin, a hormone produced by body fat. According to the Bee, blackshave higher levels of leptin than other groups. In addition,Steingraber found that exposure to household chemicals also contributesto early puberty. The report also linked early puberty with prematurebirth, low birthweight, consumption of formula as an infant, andexcessive television viewing and media use. Steingraber said some ofthe shift in puberty age can be attributed to evolutionary factors,such as improved nutrition and infectious disease control.
Girlswho have their first menstrual period before age 12 have a 50% higherrisk for breast cancer than girls who have their first period at age16, Steingraber said. Marion Kavanaugh-Lynch, an oncologist anddirector of the California Breast Cancer Research Program,said girls who menstruate early are exposed to higher levels ofestrogen, which can cause breast cancer cells to spread. Early pubertyalso is linked to emotional and social problems, the report found.Steingraber noted that girls who experience early puberty are at"higher risk of depression, early alcohol consumption, substance abuse,early first sexual encounter and unintended pregnancies."
Research, Diagnostic Efforts
According to the Bee, research into the reasons for early puberty is increasing. The Breast Cancer and the Environment Research Center in San Francisco, a federally funded project conducted by scientists at Kaiser Permanente and the University of California-San Francisco,is monitoring environmental exposure in 400 girls over several years todetermine predictors of early puberty. In addition, the five-year,state-funded California Environmental Contaminant Biomonitoring Program will measure chemical exposure in blood and urine samples from more than 2,000 California residents, the Bee reports.
Charles Wibbelsman, a pediatrician with Kaiser Permanente and a member of the American Academy of Pediatricscommittee on adolescents, said that many pediatricians are adjustingthe way that they conduct routine check-ups among girls to identifysigns of early puberty. Kavanaugh-Lynch said the report "will advance"research into early puberty and will allow researchers to "thinkcreatively about new areas of study."
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