The goal of this project is to learn about differences in bone development between children with and without type-1 diabetes (T1D). The main questions this study aims to answer are: 1. Assess how and when sex-specific bone developmental trajectories in the leg and arm will differ between children with T1D and control cohorts relative to the critical period of rapid skeletal growth in puberty. It is hypothesized that children with T1D will have inferior bone development, particularly lower gains in bone strength. 2. Assess why bone trajectories differ between T1D and control cohorts by identifying the role of body composition, site-specific muscle force and physical activity on differences in bone properties in female and male children with and without T1D. It is hypothesized that children with T1D will have lower gains in lean mass, muscle force, number of daily bone impacts and minutes of moderate-vigorous physical activity and will be associated with inferior gains in bone development. 3. Assess why T1D may impair sex-specific bone development by exploring the role of disease-related factors (e.g., duration, glucose control, hormones and markers of bone turnover) and fracture history on bone trajectories of children with T1D. It is hypothesized that longer exposure to T1D, poorer glucose control, alterations in hormones, lower bone formation markers and higher history of fracture will be negatively associated with bone trajectories of children with T1D. Participant's physical growth, bone growth, muscle strength, physical activity and nutrition habits will be assessed and followed up annually for up to 4 years.