Madsen et al. [5] evaluated OC, P1NP, and C-terminal cross-linked telopeptide of type-1 collagen (CTX) levels in individuals with T1DM aged 7.7–17.5 years and reported that these individuals had lower levels than did the reference population and that CTX levels were negatively associated with HbA1c levels. Here, CYP27A1 is linked to type 1 diabetes mellitus.