Biochemistry
BLOOD
Blood samples from the infants and their mothers were collected, as previously reported.In infants at birth, serum total 25(OH)D concentrations were measured using an automated chemiluminescent immunoassay (LIAISON analyzer; DiaSorin), as previously reported,During the trial, infant serum (200 μL) was used to measure 25(OH)DPlasma procollagen type 1 N-terminal propeptide (P1NP; Human P1NP ELISA; Creative Diagnostics) and urinary alpha telopeptide of type 1 collagen (CTX-I; EIA; Immunodiagnostic Systems) were measured as recommended