Table 1.
Characteristics of the mothers and sons at recruitment. Tapachula, Chiapas, Mexico 2002–2003
| Characteristics | % or median (IQR) n = 747 |
|---|---|
| Mothers | |
| Age at delivery | 23.7 (7.2) |
| Education (years) | |
| 0 – 6 | 35.1 |
| 7 – 9 | 31.6 |
| 10 – 12 | 23.1 |
| > 12 | 10.2 |
| Parity | |
| 1 | 41.1 |
| 2 | 34.9 |
| 3+ | 24.0 |
| Poverty statusa | |
| Poorest | 71.1 |
| Less poor | 18.6 |
| Not poor | 10.3 |
| Residence area | |
| Urban | 59.6 |
| Rural | 40.4 |
| Parental smokingb | |
| None | 84.5 |
| Dad only | 14.3 |
| Mom only | 1.1 |
| Both parents | 0.1 |
| p,p′-DDT (μg/g lipid) | 0.27 (0.67) |
| p,p′-DDE (μg/g lipid) | 2.70 (4.50) |
| Sons | |
| Birth season | |
| Winter | 19.0 |
| Spring | 28.4 |
| Summer | 28.9 |
| Fall | 23.7 |
| Underweightc | |
| No | 83.3 |
| Yes | 16.7 |
| Exclusive breastfeedingd | |
| No | 16.1 |
| Yes | 83.9 |
| Duration of breastfeeding (months) | 11.0 (12.9) |
IQR, interquartile range; SD, standard deviation
a
Defined using Mexican national standards based on monthly per capita income: Urban (Poorest, ≤672 pesos; Less poor, >672 to ≤1367; Not poor, >1367) and Rural (Poorest, ≤495; Less poor, >495 to ≤946; Not poor, >946) (Cupul-Uicab et al. 2008)
b
Smoking during pregnancy and/or anytime during follow-up
c
Weight-for-age z-scores ≤−2.00 during follow-up based on the CDC 2000 growth charts for boys
d
Median of exclusive breastfeeding, 3 days (quartiles 1 and 30.5 days)