Increased calcium intake is effective in increasing bone mineral density in children, but the effect disappears when calcium supplements are discontinued. Increased dietary calcium from daily food sources may have a greater impact on bone density than that achieved by calcium supplements. However, studies have not yet demonstrated sustained achievement of increased calcium from food sources. In addition, the effects of baseline calcium intake, bone density, and puberty status may influence bone response to increased dietary calcium. This study will develop, implement, and evaluate a Behavioral Modification-Nutrition Education (BM-NE) Intervention Program designed to promote sustained increases in dietary calcium. The study will quantify the impact of increased dietary calcium on bone density during growth and development and will determine whether the presence of risk factors for low bone density influences compliance with the program.

Participants will be recruited into two groups: a group of healthy children with no known risk factors for low bone density (i.e., no known chronic disease or previous oral steroid exposure), and a group of healthy children with potential risk factors for low bone density (previous fracture from usual childhood activities, daily dietary calcium refusal, lactose intolerance, family history of osteoporosis). Children with and without risk factors will be randomly assigned to participate in an intensive BM-NE intervention group or a usual care group that will receive counseling on bone health. The BM-NE Program will consist of five group sessions for parents and children over 6 weeks. The program will use individualized plans to increase children's calcium intake to 1500 mg per day.

Children will be followed for 3 years. Primary outcome measures will include daily calcium intake and bone mineral density. Data on height, weight, sexual and skeletal maturation, and physical activity will also be collected.