Bone Health of Obese Adolescents During Weight Loss

Context: The childhood obesity epidemic raises important clinical and public health questions about the effects of both obesity and obesity treatment on bone development. Osteoporotic fractures are a major cause of morbidity and mortality in the aged. However, peak bone mass, achieved shortly after puberty, is the key determinant of lifetime osteoporotic fracture risks. The size and direction of effects of obesity and weight loss on bone health in childhood are unclear, partly because of bone ascertainment issues. Obese children and adolescents may have elevated fracture risks, contrary to expectations based on adult data. Objectives: Primary aims of the proposed study are to: 1) characterize and compare bone health of obese and non-obese adolescents using the most accurate methods available, and 2) investigate the impact of comprehensive behavior weight control program on the bone health of obese adolescents. Study Design: Aim 1 will use a case-control design to compare bone status measures of 88 obese adolescents (ages 10 to 14 years), to be recruited for a randomized obesity treatment trial, with the same measurements of 51 contemporary non-obese control adolescents. For Aim 2, the 88 obese adolescents will be enrolled in a 12-month randomized trial, with 1:1 assignment, of a comprehensive behavioral weight control program vs. individualized nutrition education (usual care). This randomized trial is the object of this registration. Study Measures: For both aims the primary outcome will be bone strength, estimated by stress-strength index, and measured by peripheral quantitative computerized tomography (pQCT) at the tibia, a weight-bearing site.

Inclusion criteria

Eligible participants will be 10.0 to 14.9 years of age, with a body mass index (BMI) above the 97th percentile for age (~ +1.88 SD) and below +3.00 SD or less than 300 lb (~ 136 kg), whichever is lower.

Exclusion criteria

• Syndromic or secondary obesity,
• Developmental delay requiring special education,
• Depression, psychosis,
• Eating disorders that involve insufficient or excessive food intake, such as anorexia nervosa or bulimia,
• Orthopedic problems interfering with moderate to vigorous physical activity,
• Diabetes,
• Polycystic ovary syndrome,
• History of systemic corticosteroids use for more than three months cumulatively, use of immunomodulators, anticonvulsivants, weight loss medications (including diet supplements) and any other medications, or chronic conditions that could interfere with the intervention or with bone health.
• Weight loss in the preceding six months of 5% or more, participation in another weight loss program,
• Cigarette smoking (smoking and smoking cessation can affect weight and bones),
• Sexual activity without contraception and/or pregnancy,
• Subjects without a primary care provider or with a provider unwilling to provide to the research team medical information on the child will be excluded.