A Natural History of Genetic and Environmental Predictors of Pubertal Timing Among Youth With Obesity

Background: Obesity affects 1 in 5 children in the United States. Childhood obesity often persists into adolescence and adulthood. It can also raise the risk of sleep apnea, fatty liver disease, and fluid buildup in the brain and lead to early-onset puberty. This natural history study will explore how factors such as genes, hormones, diet, and chemical exposures affect puberty in children with obesity. Objective: To learn which factors predict the early start of puberty in children with obesity vs those of normal weight. Eligibility: Children aged 5 to 7 years with obesity or of normal weight. Design: Participants will have clinic visits every 6 months until they reach age 12. Each clinic visit will include these tests and procedures: A physical exam. Collection of blood, urine, and saliva samples. Some samples will be used for genetic tests. Questions about medical history and medications and supplements. A questionnaire about their physical activity over the previous week. A silicone wrist band. Participants will wear a soft wristband for a week prior to each visit. It will tell researchers what chemicals the children were exposed to during that time. Breast ultrasound, for girls. A gel will be applied, and a wand will be pressed against the skin. The wand uses sound waves to see the tissue inside the breast. DXA whole body scan. Once a year, participants will have a DXA (dual energy X-ray absorptiometry) scan. This scan measures the amount of bone, muscle, and fat in the body. Optional food diary. Parents may record everything the participant eats for two 24-hour periods ...

* INCLUSION CRITERIA: To be eligible to participate in this study, an individual must meet all of the following criteria: 1. Stated willingness to comply with all study procedures and availability for the duration of the study, including sharing medical records 2. Male or female, aged 5 to 7 years at the screening visit 3. Normal weight (defined as BMI \> 5th percentile and \ 95th percentile for age and sex) 4. Ability of parent or guardian to understand and willingness to sign a written informed consent document. And ability of the participant (child) to provide verbal assent and/or to sign a written assent document. EXCLUSION CRITERIA: An individual who meets any of the following criteria will be excluded from participation in this study: 1. Known diagnosis of syndromic/genetic form of obesity 2. Current use of medications or supplements that affect reproductive hormones (e.g., estrogen, progesterone, testosterone, puberty blockers, regular use of lavender oil or tea tree oil) 3. Chronic medical conditions (e.g., type 1 or type 2 diabetes, cancer, renal failure, lupus, etc.), at the discretion of the Principal Investigator 4. Clinically significant abnormal laboratory values, at the discretion of the Principal Investigator 5. International adoptee (associated with earlier puberty) Individuals who do not meet the criteria for participation in this study (screen failure) because of an acute, reversible or transient medical reason may be rescreened upon reversal, improvement or stabilization of their clinical status. Participants who develop an acute, reversible or transient medical condition during the study may return upon reversal, improvement or stabilization of their clinical status.