Onset of pubertal maturation in girls consists of a series of inter-related events, including reactivation of the hypothalamic-pituitary-ovarian axis, adrenarche (activation of the adrenal cortex), gonadarche (marked by the appearance of breast tissue), and pubarche (marked by the appearance of pubic hair). Researchers and clinicians have suggested several different approaches to mark and measure onset and progression of puberty, including breast development alone, onset of breast or pubic hair development (whichever is earlier), an increase in height velocity, bone age or dental age (with exposure to ionizing radiation), and menarche (a relatively late finding in puberty). There are very few studies in the scientific literature examining serial measurements of sex hormones in girls.
The Cincinnati site of the NIH-funded Breast Cancer and the Environment Research Centers (BCERC) recruited 379 girls, age 6-7 years at entry, and followed these girls every six months with assessment of multiple measures by trained examiners. These assessments included (among others) height, weight, maturation, biannual blood specimens for hormone analysis, and annual urine and blood specimens for biomarker analysis.
This presentation will discuss the results of 175 girls who entered puberty during the first three years of the project. Longitudinal comparisons of growth velocity, breast as well as pubic hair stage, and sex hormones will be presented. The sex hormones analyzed include the female hormones estradiol and estrone; the male hormone testosterone; the adrenal hormone DHEA-S; and sex hormone binding globulin (SHBG). Derived variables will include ratio of estradiol to testosterone, and free androgen index (FAI, [testosterone concentration] / SHBG).