A recent study shows that in the United States of America, the number of girls reaching puberty by the age of seven has doubled in the last decade. Scientists are still investigating the reasons, but early conclusions point towards obesity and the ingestion of chemicals which mimic the female hormone, oestrogen.
Research conducted by a team of American scientists* and revealed in the study “ Pubertal Assessment Method and Baseline Characteristics in a Mixed Longitudinal Study of Girls”, published in Pediatrics, the Official Journal of the American Academy of Pediatrics, shows startling revelations: namely that the number of white girls reaching puberty by seven has doubled since the year 1997.
The investigation was carried out on a multisite cohort of 1,239 girls taken from three different US sites (East Harlem, New York; greater Cincinnati metropolitan area and San Francisco Bay area in California) and revealed that while in 1997 the number of white girls showing breast development stage 2 consistent with the onset of puberty represented 5 per cent of the total, now in 2010 the figure has jumped to 10.4 per cent.
For Marcia Herman-Giddens, of the University of North Carolina, leader of the study carried out in 1997, the results are “extremely concerning”. She explains that “to have that much change in such a short time, it has to be the environment”. However, the study also shows a decline in the number of black girls reaching early puberty from 48 per cent to 43 per cent.
For the leader of the research team, Frank Biro (Cincinnati Children’s Hospital Medical Center, Ohio) there is a clear indication that the number of black girls reaching puberty by seven or eight years of age is levelling off while the number of white girls is rising.
“Part of it is the increase in overweight and obese girls,” he explains, stating that extra fat cells release hormones which lead towards early puberty. According to the researchers, another factor could be the presence of the female hormone oestrogen in the environment (contained in plastics) or in foodstuffs such as soya.
Investigations continue, however the question is raised as to exactly what research has been done into the possibly harmful effects of consuming the foodstuffs which appear on the shelves of our supermarkets.
*Frank M. Biro, MDa, Maida P. Galvez, MD, MPHb, Louise C. Greenspan, MDc, Paul A. Succop, PhDd, Nita Vangeepuram, MDb, Susan M. Pinney, PhDd, Susan Teitelbaum, PhDb, Gayle C. Windham, PhDe, Lawrence H. Kushi, ScDf, Mary S. Wolff, PhDb
a Division of Adolescent Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio;
bDepartment of Community and Preventive Medicine, Mount Sinai School of Medicine, New York, New York;
cDepartment of Pediatrics, Kaiser Permanente, San Francisco, California;
dDepartment of Environmental Health, University of Cincinnati College of Medicine, Cincinnati, Ohio;
eCalifornia Department of Public Health, Richmond, California; and
fDivision of Research, Kaiser Permanente Northern California, Oakland, California
Pediatrics, DOI: 10.1542/peds.2009-3079