- id
ID, unique id of each child (numeric)
- age
Decimal age, 0-2.68 years (numeric)
- sex
Sex, "male" or "female" (character)
- ga
Gestational age, completed weeks (numeric)
- bw
Birth weight in grammes (numeric)
- hgt
Height measurement in cm (numeric)
- hgt_z
Height in SDS relative Fourth Dutch Growth Study 1997 (numeric)