Sex steroids, particularly estrogen, play an important role in increasing and maintaining bone mineral density (BMD) during puberty; sex steroids also promote bone maturation.1-3 To assess the relation between bone maturation and bone mineralization during exposure to excessive estrogen, we evaluated the BMD of patients with precocious puberty associated with advanced bone age.
Patients and Methods. We measured spinal BMD in 7 untreated girls with central precocious puberty (age range, 6.0-11.3 years), all with a history of breast development before 8 years of age. The patients' breast development was Tanner stage II through IV. Bone age, assessed by means of the TW2 RUS method for Japanese,4 was found to be advanced (bone age–chronological age ratio, 1.11-1.62). Bone mineral density was measured using dual-energy x-ray absorptiometry (Hologic QDR-2000, Hologic Inc, Waltham, Mass) at the lumbar spine (L2-4). Normal BMD values for Japanese 5 to 15 years of age were