Table 1.
Characteristics of the studied population of three Pelotas birth cohort studies
| 1982 cohort | 1993 cohort | 2004 cohort | ||||
|---|---|---|---|---|---|---|
| n | % | n | % | n | % | |
| Maternal pre-pregnancy BMI category | ||||||
| Underweight | 388 | 7·8 | 412 | 9·8 | 181 | 8·3 |
| Normal weight | 3486 | 70·3 | 2992 | 70·8 | 1470 | 67·5 |
| Overweight | 875 | 17·6 | 669 | 15·8 | 391 | 18·0 |
| Obese | 212 | 4·3 | 151 | 3·6 | 136 | 6·2 |
| Socio-economic variables at birth | ||||||
| Maternal schooling in years | ||||||
| 0–4 | 1959 | 33·3 | 1185 | 27·3 | 464 | 14·8 |
| 5–8 | 2444 | 41·4 | 2000 | 46·1 | 1269 | 40·6 |
| 9–11 | 652 | 11·1 | 787 | 18·1 | 1053 | 33·7 |
| ≥ 12 | 834 | 14·2 | 370 | 8·5 | 340 | 10·9 |
| Maternal age in years | ||||||
| < 20 | 912 | 15·5 | 788 | 18·1 | 619 | 19·6 |
| 20–25 | 2193 | 37·2 | 1470 | 33·8 | 1051 | 33·4 |
| 26–30 | 1485 | 25·2 | 1080 | 24·9 | 686 | 21·7 |
| > 30 | 1305 | 22·1 | 1008 | 23·2 | 799 | 25·3 |
| Maternal variables | ||||||
| Parity | ||||||
| 1 | 2318 | 39·3 | 1561 | 35·9 | 1254 | 39·8 |
| 2 | 1653 | 28·1 | 1234 | 28·4 | 849 | 26·9 |
| ≥ 3 | 1923 | 32·6 | 1552 | 35·7 | 1052 | 33·3 |
| Maternal smoking during pregnancy | ||||||
| No | 3797 | 64·4 | 2864 | 65·9 | 2253 | 71·4 |
| Yes | 2099 | 35·6 | 1483 | 34·1 | 903 | 28·6 |
| Birth conditions | ||||||
| Gestational age | ||||||
| < 37 weeks | 291 | 6·2 | 426 | 11·0 | 420 | 13·3 |
| ≥ 37 weeks | 4367 | 93·8 | 3446 | 89·0 | 2727 | 86·7 |
| Birth weight (g) | ||||||
| < 2500 | 570 | 9·7 | 425 | 9·8 | 287 | 9·1 |
| 2500–< 3000 | 1517 | 25·8 | 1156 | 26·8 | 811 | 25·7 |
| 3000–< 3500 | 2190 | 37·1 | 1694 | 39·0 | 1264 | 40·1 |
| ≥ 3500 | 1614 | 27·4 | 1059 | 24·4 | 793 | 25·1 |
| Offspring anthropometry and body composition | ||||||
| Mean age at body composition assessment (years) | ||||||
| Mean | 30·2 | 22·6 | 10·9 | |||
| sd | 0·3 | 0·3 | 0·3 | |||
| Mean BMI (kg/m2) | ||||||
| Mean | 26·8 | 25·1 | 19·6 | |||
| sd | 5·5 | 5·2 | 4·2 | |||
| Mean waist circumference (cm) | ||||||
| Mean | 84·8 | 85·7 | 66·2 | |||
| sd | 12·6 | 11·9 | 9·5 | |||
| Fat mass index (%) | ||||||
| Mean | 31·8 | 29·8 | 27·6 | |||
| sd | 11·5 | 12·6 | 10·9 | |||
| Lean mass index (%) | ||||||
| Mean | 64·4 | 65·8 | 69·0 | |||
| sd | 10·6 | 11·7 | 10·4 | |||
| Height (cm) | ||||||
| Mean | 167·7 | 167·5 | 145·4 | |||
| sd | 9·2 | 9·5 | 7·4 | |||