Bone marker concentration assessment
At the 10-year physical examination, serum bone turnover markers were measured in 2264 children. Of these children, 17.8% (402/2264) were also invited for over-night fasting blood sampling (the fasting children means that the children should not take food, juice, mild, etc. before the blood collection. children who are fasting have a significantly higher body mass index [BMI] compared to non-fasting children (Thiering et al., 2013)). The collected blood samples were centrifuged after collection and stored frozen at −80 °C until assayed for bone turnover marker concentrations.