Sobering Development: Falling Pubertal Age in Girls
Sobering Development: Falling Pubertal Age in Girls
Abstract & Commentary
By Russell H. Greenfield, MD, Editor
Synopsis: In a much-publicized study on the physical maturation of young girls in three distinct areas of the United States, researchers found a persistence of early attainment of puberty in African American girls and an increased proportion of Caucasian girls who had reached puberty at ages 7 and 8 years. The study leaders delineate physical and psychological risks associated with early maturation and posit that an explanation for such findings might be some combination of increasing toxic environmental and food exposures.
Source: Biro FM. Pubertal assessment method and baseline characteristics in a mixed longitudinal study of girls. Pediatrics 2010;126:e583-e590.
The authors of this cross-sectional longitudinal study sought to describe methods for assessing pubertal stage of development that were effective across multiple sites, and to report the maturation stages of a cohort of girls aged 7-8 years. Data collection occurred at three sites across the United States representing the northeast, the midwest, and the west coast. Girls were aged 6-8 years at the time of enrollment and designated by race/ethnicity. Pubertal assessment was categorized using Tanner and Marshall criteria for breast maturation and pubic hair stages. Staff was trained in the method of assessment in depth, and great lengths were taken to ensure consistent inter-rater agreement across the sites. Logistic regression models were used to examine factors that might impact pubertal stage and linear regression models employed to estimate the strength of the relationship between height velocity, a biological change associated with pubertal maturation, and other factors.
At baseline 1,239 girls were enrolled, composed of approximately 34% Caucasian (C), 31% African American (AA), 30% Hispanic (H), and 5% Asian (A) subjects. At age 7 years, stage of breast maturation was greater than or equal to 2 in 10% of C subjects, 23% of AA girls, and 15% of H participants. At age 8 years, breast maturation stage was greater than or equal to 2 in 18%, 43%, and 31%, respectively. The proportion of subjects who had attained breast stage greater than or equal to 2 at age 7 years was much higher specifically for C subjects than was reported in a 1997 study, and it remained high for AA girls.
Commentary
It has long been recognized from epidemiologic data that risk factors for breast cancer include early age of menarche, a period considered critical in terms of factors that might make a women more or less susceptible to the disease later in life. In recognition of this, the Breast Cancer and the Environment Research Centers (BCERC) consortium was developed in 2003 to research prepubertal and pubertal maturation, and also to focus on the potential impact of specific environmental factors on rapidly developing breast tissue. Accumulated research data show a continued trend toward earlier onset of breast development in young girls.
One of the strengths of the current trial is the standardized protocol for pubertal staging that was employed, as well as significant oversight by study directors to ensure "substantial" agreement between examiners. Another was choice of three different locales within the United States (New York, Cincinnati, and San Francisco). Of note, there were significant baseline differences between the sites regarding the proportion of subjects who had entered into puberty. Some experts believe such differences most likely occur as a result of unique local toxic exposures, for example to endocrine-disrupting chemicals, whereas others cite regional differences in dietary practices. In light of different farming methods currently in use regionally, the latter still could be considered for analysis of environmental influences in the maturation of young girls.
The proportion of AA girls attaining puberty at an early age remains high but largely unchanged according to data culled from more than 20 years' examination; however, the rate of breast maturation in C girls appears to be quickening. To be euphemistic, these statistics raise the spectre of some problems. The authors do a nice job describing what early sexual maturation can mean to a young girl: lowered self-esteem; earlier sexual experiences; higher rates of eating disorders, depression, and suicide attempts; and poor body image. The problems deepen when looking from the vantage point of physical health, where early puberty is associated with increased risks of breast and endometrial cancer, hypertension, hyperglycemia, and obesity.
Many in positions of authority, including physicians, have been complacent in the face of such data, often interested in them but choosing to observe instead of act. The members of the BCERC are to be commended for acting, and in ways that should help direct future actions. Many experts are concerned that only environmental factors could have hastened childhood physical development over such a short period of time, a fact that cannot be explained simply through genetic drift. Even if true, however, the sheer number of compounds with potential endocrine and other system impacts is overwhelming. The members of the BCERC have acted in a way that projects, "We have to start somewhere."
The President's Cancer Panel recently released its findings on environmental influences on cancer and ultimately called for a cohesive effort to identify and remove toxins in the environment that "increase health care costs, cripple our nation's productivity, and devastate American lives." This study supports such efforts, efforts that physicians need to get behind for the safety of our patients and loved ones. This isn't a political issue; it's a health care issue, meaning health care practitioners should take the lead. We recognize all too well what can happen to health care when we cede the leadership role to those not practiced in the healing arts... Hopefully that won't be the case as awareness of environmental impacts on health come more to the fore.
In a much-publicized study on the physical maturation of young girls in three distinct areas of the United States, researchers found a persistence of early attainment of puberty in African American girls and an increased proportion of Caucasian girls who had reached puberty at ages 7 and 8 years. The study leaders delineate physical and psychological risks associated with early maturation and posit that an explanation for such findings might be some combination of increasing toxic environmental and food exposures.Subscribe Now for Access
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