|
Herman-Giddens, ME, EJ Slora, RC Wasserman, CJ Bourdony, MV Bhapkar, GG Koch and CM Hasemeir. 1997. Secondary sexual characteristics and menses in young girls seen in office practice: a study from the pediatric research in office settings network. Pediatrics 99(4):505-512. |
|||
| Herman-Giddens et al. analyze data rating stages of sexual maturation in 17,077 girls ages 3 through 12 in the United States. Of the sample, 9.6% were African-American and 90.4% were white. | |||
| Even at the age of 3, the youngest in the study, 3% of African-American girls and 1% of white girls showed breast and/or pubic hair development, with proportions increasing to 27.2% and 6.7%, respectively, at 7 years of age. Age 8: 48.3% and 14.7%. | |||
 |
 |
||
| Prevalence of breast development at Tanner stage 2 or greater by age and race. | Prevalence of pubic hair development at Tanner stage 2 or greater by age and race. | ||
| The mean age for onset of breast development was 8.87 years for African-American girls and 9.96 years for white girls; for onset of pubic hair development mean ages were 8.78 years and 10.51 years, respectively. | |||
| Herman-Giddens et al. conclude that girls in the United States are developing pubertal characteristics earlier than the age suggested in standard pediatric textbooks and earlier than previous studies. They are unable, however, to establish with certainty whether these differences demonstrate a true shift in the age of pubertal onset because of difficulties of comparing these results with earlier studies. They suggest, however, that white girls appear to be developing 6 months to a year sooner than girls in the earlier studies. The age of menses appears to have remained stable in white girls over the past 45 years, whereas in African American girls it appears to have advanced by a little less than one-half year. | |||
| With respect to endocrine disruption, they state: "The possibility that the increasing use of certain plastics and insecticides that degrade into substances that have estrogen-related physiological effects on living things should be investigated in relation to the earlier onset of puberty. | |||