Study Background

Over the past decade, there has been an alarming trend toward earlier breast development in girls. There have been some recent reports that overweight girls are developing breast tissue earlier than normal weight girls. However, questions remain about the validity of reports of early puberty among overweight girls due to the difficulty in distinguishing fatty tissue from breast tissue in this population.

In previous studies, doctors decided whether or not a girl had breast tissue by feeling the chest. This can be a problem in overweight girls because fatty tissue in the chest can often feel like breast tissue. We think that by using breast ultrasound, we can do a better job of telling whether or not an overweight girl has breast tissue. This will help us understand if overweight girls are truly entering puberty before normal weight girls.

The study consists of 2 parts, though the second part is optional and would occur within 6 months of the first. Each part requires 2 study visits, one to the NIEHS Clinical Research Unit (CRU) in Research Triangle Park, North Carolina and one to a nearby Wake Radiology center. Study procedures include a physical exam, blood and urine tests, DXA (for body composition), hand x-ray (for bone age), and breast and transabdominal (pelvic) ultrasounds.

All girls who join the study will be compensated for their time and travel costs. Parents or legal guardians must give permission and come with his/her daughter to all study visits.