A new US study suggesting that girls may reach puberty earlier than they did 13 years ago has rekindled worries about the chemical Bisphenol A (BPA) used in the manufacture of some plastic bottles, sipper cups and food cans.
Although the study does not concern the chemical itself, critics of BPA suggest it is further evidence of its adverse impact on human health. BPA has been linked to the activity of estrogens; the main female sex hormones. The scientists who conducted the study identified rising obesity rates as a possible reason for girls reaching puberty at an earlier age.
The study, lead by Dr Frank Biro of Cincinnati Children's Hospital Medical Center and published in Pediatrics, examined about 1,200 girls aged 7 and 8 in Cincinnati, New York and San Francisco using a standard measure of breast development to determine which girls had started puberty. The scientists also talked to the girls' doctors and nurses.
The researchers found that girls, particularly white girls, were more developed at a younger age compared with a similar nationwide study conducted in 1997. At age 7, about 10 per cent of white girls and 23 per cent of black girls had started developing breasts - compared with 5 per cent of white girls and 15 per cent of black girls in 1997.
The scientists noted that girls who reach puberty earlier are more likely to engage in risky sexual behavior and may be at higher risk of breast cancer than later developers.
Meanwhile, later this week the US Maine Board of Environmental Protection will hold a public hearing on whether to ban BPA A in baby bottles and other reusable food and beverage containers.
Certified as safe
BPA supporters insist that the chemical has been tested fully and is certified as safe by all the world’s major food agencies.
Earlier this month, German Federal Institute for Risk Assessment (BfR) concluded that two major studies do not show the chemical is hazardous.
It said that the studies by Stump et al and Ryan et al provided no indications for adverse health effects on neurological development and behaviour.
But a recent US study from the University of Michigan School of Public Health suggested that urinary BPA concentrations could be related to a fall in sperm quality and concentration.
Pubertal Assessment Method and Baseline Characteristics in a Mixed Longitudinal Study of Girls
Authors: Frank Biro, Maida Galvez, Louise Greenspan, Paul Succop, Nita Vangeepuram, Mary Wolff, Susan Pinney, Susan Teitelbaum, Gayle Windham, Lawrence Kushi.