FRIDAY, Sept. 17 (HealthDay News) -- Girls growing up in higher-income homes without a biological father are likely to reach puberty earlier than others, new research finds.
"In higher-income families, father absence predicted earlier puberty, but it did not in lower-income, father-absent [households]," said study leader Julianna Deardorff.
"Girls in upper-income households without a father were at least twice as likely to experience early onset of puberty, as demonstrated by breast development," she said. The researchers defined higher income as $50,000 or more a year.
Early maturation in girls is linked with emotional and substance use problems and earlier sexual activity. These girls also face a higher risk for breast cancer and other reproductive cancers later in life.
Previous research has linked absent-father households and earlier puberty, but this study adds more information, said Deardorff, an assistant professor of public health at the University of California, Berkeley.
"We were looking at very early signs," such as breast development and the growth of pubic hair, she said. Other researchers have focused on the start of menstruation without looking at factors such as income and ethnicity, according to background information in the study.
Girls are reaching puberty earlier in the United States, where the average age of menstruation is about 12 years, Deardorff said. Recent research has found some girls starting to develop breasts as early as age 7 or 8.
For their study, published Sept. 17 in the Journal of Adolescent Health, Deardorff and her colleagues followed 444 girls, aged 6 to 8 at the start, and their mothers. They gathered extensive data on factors such as weight, height, stage of breast and pubic hair development, father's presence and income. Eighty percent of the girls said their fathers did not live with them.
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