Table 1. Variable collection methods.
| Variable | Prospective/Recalled |
| Participants (born 1983–4) | |
| Birth weight | Prospective |
| Gestational age | Prospective |
| Current height | Prospective |
| Adult household income | Prospective |
| Spouses of male participants | |
| Height | Prospective |
| Weight | Prospective |
| Offspring (of 1983–4 born parent) | |
| Birth weight | Recalled (maternally) |
| Gestational age | Recalled (maternally) |
| Twins (Yes/No) | Recalled (maternally) |
| Birth date | Recalled (maternally) |
| Weighed (Yes/No) | Recalled (maternally) |
| Live birth (Yes/No) | Recalled (maternally) |
| Weight | Recalled (maternally) |
| Gestational age | Recalled (maternally) |
| Sex | Recalled (maternally) |
| Mother worked in pregnancy | Recalled (maternally) |
| Mother received prenatal care | Recalled (maternally) |
| First born | Recalled (maternally) |
a
Male and female – mothers and fathers.