High Income, Absent Father May Lead to Early Puberty
Tuesday, September 21, 2010
Category: News > University > Research and Ideas
Over the past century, the changing voice of puberty has been arriving earlier and earlier in American children, a phenomenon that could - at least in girls - be partly attributed to a higher family income.
A study by UC Berkeley researchers published online Monday in the Journal of Adolescent Health examines the connection between an early onset of puberty in girls and environmental factors, such as the absence of a biological father in the home, body mass index, ethnicity and family income.
Earlier puberty for women is linked to breast cancer later in life and can increase the likelihood of teen pregnancy and substance abuse, said Julianna Deardorff, the study's lead author and an assistant professor in the UC Berkeley School of Public Health.
While the effects of a missing biological father and body mass index have been studied in previous research and ethnicity plays an important role, according to Deardorff, the effects that a family's income have on puberty had not been taken into consideration prior to this study.
"Income has (been of) interest (to researchers) for a while now, particularly because we know that extreme malnutrition, which doesn't typically happen in the United States, has been linked to delayed puberty," she said. "There's some suspicion that puberty in this country may be linked to food choices - higher caloric-density food - and that might affect female development."
However, Deardorff said the results of the income portion of the study were not what she expected. The research team, which included researchers from the Kaiser Permanente Northern California Division of Research, UC San Francisco and UC Berkeley, anticipated that girls in lower income families would undergo puberty earlier.
But in fact, girls in families without a biological father that made $50,000 or more experienced puberty earlier than those in lower income families did, leading to a conclusion the researchers said they do not quite understand yet themselves.
According to Larry Kushi, co-author of the study and associate director of etiology and prevention at the Kaiser Permanente Northern California Division of Research, researchers do not yet have a hypothesis as to why girls of higher incomes would experience puberty earlier.
Deardorff suggested factors such as nutrition, increased exposure to artificial lighting from televisions and computers and exposure to beauty products and chemicals may shed light on the phenomenon, but that none of these explanations fully account for the discrepancies in pubertal onset as they relate to income.
"This article brings up more questions than it answers in some ways," Deardorff said.
While previous studies on puberty have relied on information gathered after the fact, the UC Berkeley research has monitored 444 girls 6 to 8 years old since 2005, Deardorff said. Researchers plan to monitor the girls for five more years.
Claire Perlman covers research and ideas. Contact her at [email protected]
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