Is BPA making our kids grow up faster?

This was originally published at Washington Toxics Coalition.

A lot has changed for kids growing up these days. But besides the obvious factors, like the ubiquity of cell phones, more fundamental changes have been taking place.

Today, it’s not unusual for a seven year-old to look in the mirror and discover she’s started to grow breasts.

That’s what researchers found when they examined more than 1200 girls in California, Ohio, and New York. A recent study published in the journal Pediatrics found that times have changed when it comes to the start of puberty for girls.

Among the white girls in the study, more than 10% of the seven year-olds had started breast development—twice as many as in a study from the mid-1990s.

Rates are even higher for black and Hispanic girls, with about 23% of black and 15% of Hispanic seven year-olds having started development, though the increase over time was not as great.

This isn’t the first study to suggest that puberty is coming earlier for today’s generation, and a number of causes are postulated for these changes in the timing of puberty. They include low birth weight and premature birth, greater rates of obesity, lack of breastfeeding, stress, inactivity, and exposure to hormone-disrupting chemicals.

"Variations in the timing of pubertal maturation may be sensitive “sensors” of the effects of environmental exposure in human populations."

Pediatrics, "Pubertal Assessment Method and Baseline Characteristics in a Mixed Longitudinal Study of Girls"

Previous studies have indicated that, on average, girls now get their periods a few months earlier and develop breasts one to two years earlier than girls did 40 years ago.

Going through puberty can have serious impacts on social development and health. Girls who mature earlier have lower self-esteem and poorer body image, and are more likely to have problems like eating disorders and depression. Later in life, they are more likely to develop breast or endometrial cancer.

Accidental exposure to toxic chemicals, such as when farm families in Michigan were exposed to high levels of the flame retardant PBB, has been implicated in some cases of early puberty. Laboratory studies on chemicals such as Bisphenol-A (BPA) have also indicated that exposure to hormone disrupting chemicals during critical times of development may cause early puberty.

Factors such as low birth weight, formula feeding, obesity, and toxic exposures are all interrelated, and it will be some time before researchers and physicians tease out the complicated story of why our children are becoming adults earlier than we did. In the meantime, we can take a closer look at toxic chemicals that may be upsetting the delicate hormonal processes that control puberty.