A Study of Physical and Metabolic Abnormalities in HIV Infected and Uninfected Children and Youth

Inclusion Criteria For HIV uninfected participants (Group 1) * HIV-1 negative (perinatally HIV-exposed but uninfected participants are eligible) For HIV infected participants (Groups 2 and 3) * Mother-to-child (vertically) transmitted HIV infection * Confirmed diagnosis of HIV-1 infection by two positive assays from two different samples * For Group 2, cannot have taken a PI-containing regimen in the 12 months prior to study entry or have ever received a PI for 2 or more weeks * For Group 3, must currently be taking the same PI-containing regimen taken continuously for at least 12 months prior to study entry For all participants * Accessible medical and medications history * Parent, legal guardian, or participant willing to give informed consent and willing to comply with study requirements * Females who have begun menstruating must have negative pregnancy test Exclusion Criteria * Receipt of certain medications, including growth hormone, megestrol acetate, anabolic agents, anticytokine agents, systemic ketoconazole, systemic glucocorticoids (except if receiving stable physiologic doses), or drugs to treat osteoporosis * Type II diabetes mellitus and unable to omit medication prior to specimen collection * Pregnancy within the last 12 months, currently pregnant, or breastfeeding * History of eating disorder