Weight, length, head circumference and BMI in infants
The weight, length and head circumference in infants were measured to assess infant's physical growth at the baseline, at the end of the 2- and 5-month intervention by one investigator, who was blinded from group division. The weight and length were measured by using an intelligent physical examination instrument (WS-RTG-ID, Wuhan Computer Software Development Co. LTD, China). Body mass index (BMI) was also calculated by using the following formula: BMI= weight (kg) /length (m)