Table 1.
Characteristics of sample according to the variables studied (The 1993 Pelotas Birth Cohort, Brazil) (Number of participants and percentages; mean values and standard deviations; median values and interquartile ranges (IQR))
| Total | Male | Female | ||||
|---|---|---|---|---|---|---|
| Variables | n | % | n | % | n | % |
| Birth order | ||||||
| First born | 1634 | 39·8 | 791 | 39·3 | 843 | 40·4 |
| Second | 1225 | 29·9 | 603 | 29·9 | 622 | 29·8 |
| Third | 652 | 15·9 | 311 | 15·4 | 341 | 16·3 |
| Fourth or later | 592 | 14·4 | 311 | 15·4 | 281 | 13·5 |
| Younger siblings | ||||||
| 0 | 1621 | 41·5 | 770 | 41·2 | 851 | 42·0 |
| 1 | 1300 | 33·4 | 617 | 33·0 | 683 | 33·7 |
| 2 | 545 | 14·0 | 286 | 15·3 | 259 | 12·8 |
| ≥ 3 | 431 | 11·1 | 197 | 10·5 | 234 | 11·5 |
| Total siblings | ||||||
| 0 | 470 | 12·1 | 216 | 11·6 | 254 | 12·5 |
| 1 | 1198 | 30·8 | 560 | 30·0 | 638 | 31·6 |
| 2 | 963 | 24·7 | 466 | 25·0 | 497 | 24·5 |
| ≥ 3 | 1263 | 32·4 | 626 | 33·4 | 637 | 31·4 |
| Maternal skin colour | ||||||
| White | 3155 | 76·9 | 1562 | 77·4 | 1593 | 76·3 |
| Black | 763 | 18·6 | 361 | 17·9 | 402 | 19·3 |
| Other | 186 | 4·5 | 95 | 4·7 | 91 | 4·4 |
| Pregnancy smoking consumption | ||||||
| Yes | 1349 | 32·9 | 644 | 31·9 | 705 | 33·8 |
| No | 2757 | 67·1 | 1374 | 68·1 | 1383 | 66·2 |
| Pregnancy alcohol consumption | ||||||
| Yes | 212 | 5·2 | 91 | 4·5 | 121 | 5·8 |
| No | 3894 | 94·8 | 1927 | 95·5 | 1967 | 94·2 |
| Gestational systemic hypertension | ||||||
| Yes | 631 | 15·7 | 332 | 16·8 | 299 | 14·6 |
| No | 3398 | 84·3 | 1645 | 83·2 | 1753 | 85·4 |
| Gestational diabetes | ||||||
| Yes | 108 | 2·7 | 51 | 2·6 | 57 | 2·8 |
| No | 3911 | 97·3 | 1918 | 97·4 | 1993 | 97·2 |
| Presence of the father | ||||||
| Yes | 3618 | 88·1 | 1766 | 87·5 | 1852 | 88·7 |
| No | 488 | 11·9 | 252 | 12·5 | 236 | 11·3 |
| Maternal education (completed years) | 4099 | 2014 | 2085 | |||
| Mean | 6·8 | 6·8 | 6·7 | |||
| sd | 3·5 | 3·5 | 3·5 | |||
| Maternal age at birth (years) | 4105 | 2017 | 2088 | |||
| Mean | 26·1 | 26·1 | 26·1 | |||
| sd | 6·4 | 6·5 | 6·3 | |||
| Maternal height* (cm) | 3780 | 1832 | 1948 | |||
| Mean | 157·7 | 157·6 | 157·8 | |||
| sd | 6·7 | 6·3 | 7·0 | |||
| Gestational weight gain (g) | 3953 | 1940 | 2013 | |||
| Mean | 11·7 | 11·9 | 11·6 | |||
| sd | 5·9 | 5·9 | 5·8 | |||
| Family income (MMW) | 4035 | 1989 | 2046 | |||
| Median | 2·6 | 2·5 | 2·8 | |||
| IQR | 1·5–4·6 | 1·5–4·5 | 1·5–4·8 |
MMW, monthly minimum wages.
*
Maximum percentage of unknown observations: (n 326; 7·9 %) for the maternal height variable.