PTH, 25-OHD, 1,25(OH)2D, and FECa in the three groups. The two bars for each group represent study visits 1 and 2 as previously described. Means and sebars are shown. A and B, There were no statistical differences among groups or time points in regard to PTH or plasma 25-OHD; C, plasma 1,25(OH)2D was significantly lower in the bottle-feeding group compared with both lactation and control groups at baseline; D, There were no statistical differences among groups in regard to FECa at baseline, but in the time period between the two study visits, FECa significantly increased in the lactation group (P = 0.023). FECa remained stable in the control and bottle-feeding groups.