Table 1.
Description of the variables in the three Pelotas birth cohort studies
| Pelotas Cohort |
|||
|---|---|---|---|
| 1982 | 1993 | 2004 | |
| Cohort total | 5914 | 5249 | 4287 |
| Median of maternal education (years) | 5.5 | 6.2 | 8.0 |
| Low maternal BMI (<18.5 kg/m2, %) | 7.8 | 8.9 | 4.9 |
| Median duration (months) of | |||
| Any breastfeeding | 2.9 | 3.0a | 6.2 |
| Exclusive breastfeeding | –b | 0.1a | 1.2 |
| Predominant breastfeeding | 2.0 | 1.9a | 2.5 |
| Median age (months) at the introduction of | |||
| Cow's milk | 3.1 | 2.0a | 3.1 |
| Formula | 2.2 | 1.6a | 1.6 |
| Fruits | 3.3 | 3.5a | 4.1 |
| Vegetables/legumes | 3.7 | 4.0a | 5.0 |
| Mean environmental temperature according to trimester of birthc | |||
| January–March | 22.2 (2.2) | 23.1 (2.0) | 22.5 (1.9) |
| April–June | 15.9 (4.0) | 16.1 (4.5) | 16.2 (4.3) |
| July–September | 14.7 (3.6) | 12.6 (3.6) | 14.3 (3.6) |
| October–December | 19.1 (3.5) | 20.2 (3.0) | 19.2 (2.9) |
| Mean environmental temperature in the 1st month of lifec | |||
| Coldest quintile | 12.8 (0.6) | 11.7 (0.7) | 13.2 (0.6) |
| Quintiles 2–4 | 18.1 (2.4) | 18.0 (3.1) | 17.9 (2.7) |
| Hottest quintile | 23.1 (0.4) | 23.0 (0.8) | 23.0 (0.6) |
aWeighted results for a sample of all low birthweight children and a systematic sample of 20% of the remaining children.
bNot available but assumed to be less than 1 week based on key informants.
cMean and standard deviation.