Table 1.
Demographic characteristics of Bangladesh and Mexico cohorts
| Characteristics | Mean (SD) or n (%) | |
|---|---|---|
| Bangladesh (n = 497) |
Mexico (n = 390) |
|
| Maternal educationa | ||
| High education | 266 (53.5%) | 231 (59.2%) |
| Low education | 231 (46.5%) | 159 (40.8%) |
| Maternal marital status at delivery | ||
| Married or living with partner | 497 (100%) | 316 (81.0%) |
| Single, separated, or divorced | 0 (0%) | 74 (19.0%) |
| Prenatal exposure to second-hand smoke | ||
| Smoker living in home | 207 (41.6%) | 140 (35.9%) |
| No smoker living in home | 290 (58.4%) | 250 (64.1%) |
| Child gender | ||
| Male | 241 (48.5%) | 209 (53.6%) |
| Female | 256 (51.5%) | 181 (46.4%) |
| Delivery type | ||
| Vaginal (including forceps) | 303 (61.0%) | 192 (49.2%) |
| Cesarean section | 194 (39.0%) | 198 (50.8%) |
| Maternal age (years) | 22.8 (4.3) | 27.7 (5.5) |
| Gestational age (weeks) | 38.1 (1.7) | 38.5 (1.6) |
| Birth weight (kg) | 2.86 (0.40) | 3.10 (0.43) |
| Head circumference (cm) | 32.76 (1.43) | 34.28 (1.48) |
| Cord blood Pb (μg/dL) | 5.10 (6.51) | 3.83 (2.70) |
| Bayley Scales of Infant Development, 24 months | ||
| Mental composite raw score | 112.7 (10.4) | 108.6 (9.8) |
| Motor composite raw score | 92.7 (5.0) | 91.7 (4.5) |
aMaternal education in Mexico cohort: < high school or ≥ high school. Maternal education in Bangladesh cohort: < primary school or ≥ primary school