Table 1.
Participants’ characteristics.
| Characteristic | Overall (n = 919) | Male (n = 472) | Female (n = 447) |
|---|---|---|---|
|
| |||
| Continuous variables | |||
| Asset index [(median, (IQR)] | −0.37 (−1.28,0.85) | −0.39 (−1.32, 0.94) | −0.36 (−1.25, 0.84) |
| Maternal age at enrollment, years [mean, (sd)] | 28.1 (7.2) | 27.7 (7.3) | 28.6 (7.0) |
| Maternal BMI, kg/m2, [mean, (sd)] | 23.4 (3.4) | 23.5 (3.3) | 23.3 (3.5) |
| Parity [(median, IQR)] | 2.0 (1.0, 4.0) | 2.0 (1.0, 4.0) | 3.0 (1.0, 4.0) |
| Gestational age at birth, wk [mean (sd)] | 39.2 (1.7) | 39.1 (1.59) | 39.3 (1.79) |
| Birthweight, Kg [mean, (sd)] | 2.90 (0.46) | 2.93 (0.47) | 2.87 (0.46) |
| Average prenatal CO, ppm | |||
| Mean (sd) | 1.33 (1.00) | 1.33 (0.90) | 1.33 (1.09) |
| Median (IQR) | 1.11 (0.69, 1.72) | 1.11 (0.72, 1.70) | 1.11 (0.64, 1.75) |
| Child average postnatal CO, ppm | |||
| Mean (sd) | 0.88 (1.39) | 0.89 (1.63) | 0.87 (1.07) |
| Median (IQR) | 0.53 (0.24, 1.02) | 0.51 (0.23, 0.99) | 0.58 (0.27, 1.03) |
| Prenatal PM2.5, μg/m3 | |||
| Mean (sd) | 85.77 (58.56) | 88.39 (63.13) | 82.97 (53.26) |
| Median (IQR) | 70.40 (43.32, 107.46) | 70.47 (43.70, 110.31) | 69.72 (42.87, 101.80) |
| Missing n (%) | 391 (42.5) | 200 (42.4) | 191 (42.7) |
| Maternal postnatal PM2.5, μg/m3 | |||
| Mean (sd) | 65.83 (40.15) | 66. 28 (41.93) | 65.34 (38.27) |
| Median (IQR) | 55. 64 (37.26, 83.84) | 56.81 (35.39, 83.75) | 55.23 (38.67, 85.89) |
| Missing n (%) | 438 (47.7) | 225 (47.7) | 213 (47.7) |
| Categorical variables [(n (%)] | |||
| Ethnicity | |||
| 1 | 163 (17.7) | 73 (44.8) | 90 (55.2) |
| 2 | 121 (13.2) | 62 (51.2) | 59 (48.8) |
| 3 | 596 (64.9) | 312 (52.3) | 284 (47.7) |
| 4 | 39 (4.2) | 25 (64.1) | 14 (35.9) |
| Second-hand tobacco exposure | 189 (20.6) | 93 (19.7) | 96 (21.5) |
| Low birth weight | 149 (16.6) | 71 (15.5) | 78 (17.7) |
| Missing | 20 | 15 | 5 |
| Small for gestational age | 196 (21.8) | 92 (20.1) | 104 (23.5) |
| Preterm Birth | 33 (3.6) | 17 (3.6) | 16 (3.6) |
| Missing | 2 | 1 | 1 |
| Breastfeeding at 1 year | 911 (99.2) | 469 (99.6) | 442 (98.9) |
| Missing | 1 | 1 | 0 |
| Maternal Education | |||
| None | 376 (40.9) | 197 (52.4) | 179 (47.6) |
| Primary | 245 (26.7) | 133 (54.3) | 112 (45.7) |
| Middle/Junior High School | 258 (28.1) | 127 (49.2) | 131 (50.8) |
| Secondary/post-secondary | 40 (4.4) | 15 (37.5) | 25 (62.5) |
| Season of birth | |||
| Dry | 534 (58.1) | 276 (51.7) | 258 (48.3) |
| Rainy | 385 (41.9) | 196 (50.9) | 189 (49.1) |