highly significantP < 0.001
There was a highly significant positive correlation between baseline and 12 months serum 25(OH)D in both the DD and DP groups (r = 0.40 and r = 0.69, respectively ( P < 0.001)), and a significant negative correlation between baseline and delta serum 25(OH)D (r = - 0.57 and r = - 0.49, respectively ( P < 0.001)).