Hauta-Alus HH, Holmlund-Suila EM, Kajantie E, et al. - In this randomized, double-blinded intervention study, researchers sought to examine how maternal and child 25-hydroxyvitamin D [25(OH)D] and vitamin D supplementation impact growth during the first 2 years of life. The authors discovered that toddlers born to mothers with pregnancy 25(OH)D > 125 nmol/L were at 2 years lighter and thinner compared with the reference group with 25(OH)D 50-74.9 nmol/L. Toddlers in the highest quartile of 25(OH)D were shorter, lighter and thinner compared with the lowest quartile. There may be an inverse U-shaped relationship with vitamin D and early childhood growth.