We propose to examine the following research question:

What aspects of the child's diet are related to bone structure in children either before and/or during puberty (depending on when the measures were made)?

Aspects of the diet will include:

• Overall assessment of the diet using dietary patterns
• Individual nutrients
• Individual foods and food groups
• Longitudinal measures of dietary effects (from prenatal to the current time)

Aspects of the bone structure to be examined will include:

• Bone size (assessed by area of the whole skeleton derived from total body DXA scans, width of the femoral neck derived from DXA scans of the hip, and cross sectional area of the tibia derived from pQCT scans).
• Bone shape (reflected by the ratio of length and width of the humerus based on a novel method we have recently developed19).
• Cortical thickness (based on hip DXA scans and tibial pQCT scans).
• Trabecular bone mass (based on bone mineral density (BMD) of the spine obtained from sub-regional analysis of total body DXA scans).
• Bone strength (reflected by cross sectional moment of inertia derived from hip DXA scans and tibial pQCT scans).