Fig. 3: Forest plots comparing the long-term (after 40 weeks’ postmenstrual age or at the outpatient clinic follow-up) outcomes between the high-dose and low-dose vitamin D supplementation for preterm infants.

A Long-term outcomes: continuous variables. B Long-term outcomes: categorical variables. CI confidence interval, MD mean difference, RD risk difference, 25(OH)D 25-hydroxyvitamin D.