Study population
This is a cross-sectional descriptive study approved by the Human Ethics
Committee of Thammasat University No. 1 (Faculty of Medicine). Infants
aged 6 to12 months who attended the Well Baby Clinic at Thammasat
University Hospital, from June 2016 to June 2017, were recruited
randomly after informed consent was granted by their parents or legal
guardians. Our inclusion criteria were term newborns (38-42 weeks
gestation) with a birth weight between 2500-4000 grams having no
prenatal and perinatal complications such as severe birth asphyxia,
severe respiratory distress, or neonatal intensive care unit admission.
Infants with chromosome abnormalities/syndromes, infectious/inflammatory
diseases, and any acute health problems were excluded. All clinical
samples from enrolled subjects were collected before routine universal
iron supplementation. We collected demographic/clinical data through
direct interviews with two investigators (PSi and PSu). Weight and
length of participants were measured and evaluated by Z-score, according
to WHO guidelines.26 The Z-scores of
weight-for-lengths below or above two standard deviations (SD) are
categorized as underweight and overweight, respectively.