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A study published in the medical journal Pediatrics on Monday found that 7-year-old girls are showing signs of breast development in higher numbers than in previous years. In 1997 a nation-wide study of 3 to 12 year-old’s found that it was surprisingly common for girls as young as 7 and 8 to have begun developing breasts or growing pubic hair. This most recent study, led by Dr. Biro of the Cincinnati Children’s hospital, found that the trend toward early puberty is continuing. The findings were based on a cohort of 1,239 girls from 3 different cities, racially comprised of a third each White, Black, and Latino. The percentage of white girls developing breasts at age 7 increased the most over the years compared to their black and Latino counterparts. It was already known that Black and Latino girls hit puberty earlier than their white peers. Obesity and environmental toxins are thought to be the two major factors influencing the early on-set of puberty. Body fat produces estrogen, a hormone required for menstruation and breast development. Dr. Biro said that while obesity plays a role, the study also was a “wake-up call” regarding the effects of environmental toxins. He told the New York Times, “It’s certainly throwing up a warning flag. We need to think about the stuff we’re exposing our bodies to and our kids bodies.” Girls who begin puberty early are more likely to experience mental health and medical problems later in life.

Guest: Dr. Sarah Pitts, Division of Adolescent/Young Adult Medicine at Children’s Hospital Boston