Table 1.
Characteristics of study participants overall and by third trimester black carbon (BC) exposure
| Quartiles of third trimester BC | |||||
|---|---|---|---|---|---|
| 3rd trimester BC (µg/m3), Mean (SD) | Total 0.69 (0.23) |
Q1 (lowest) 0.40 (0.09) |
Q2 0.60 (0.05) |
Q3 0.76 (0.05) |
Q4 (highest) 1.00 (0.14) |
| Mean (SD) or % | Mean (SD) or % | ||||
| Maternal characteristics | |||||
| Age at enrollment (years) | 32.1 (5.2) | 33.0 (4.3) | 32.7 (5.1) | 31.5 (5.6) | 31.2 (5.8) |
| Prepregnancy BMI (kg/m2) | 24.8 (5.3) | 24.6 (5.2) | 24.8 (5.6) | 24.6 (5.0) | 25.3 (5.6) |
| College graduate (%) | 68 | 78 | 71 | 66 | 58 |
| Smoking habits (%) | |||||
| Never | 69 | 67 | 68 | 70 | 71 |
| Former | 20 | 24 | 21 | 18 | 18 |
| During pregnancy | 11 | 10 | 11 | 12 | 11 |
| Glucose tolerance (%) | |||||
| Normal | 83 | 82 | 82 | 85 | 85 |
| Failed GCT, normal OGTT | 9 | 11 | 10 | 6 | 7 |
| IGT | 3 | 3 | 3 | 3 | 4 |
| GDM | 5 | 5 | 5 | 6 | 4 |
| Neighborhood characteristics | |||||
| Median household income in census tract ($)a | 57,763 (21,656) | 70,993 (20,006) | 60,396(20,411) | 53,505(20,740) | 45,508 (17,035) |
| Child characteristics in infancy | |||||
| Gestational age (weeks) | 39.5 (1.8) | 39.5 (1.7) | 39.4 (1.8) | 39.6 (1.6) | 39.5 (1.8) |
| Birth weight-for-gestational age z-score | 0.20 (0.97) | 0.32 (1.02) | 0.20 (0.93) | 0.19 (0.96) | 0.06 (0.94) |
| Sex (%) | 49 | 47 | 50 | 49 | 49 |
| Race/ethnicity (%)b | |||||
| White | 64 | 84 | 67 | 56 | 47 |
| Black | 17 | 5 | 14 | 24 | 25 |
| Hispanic | 6 | 1 | 6 | 5 | 11 |
| Asian | 5 | 3 | 5 | 6 | 4 |
| Other | 9 | 7 | 8 | 9 | 13 |
| Early childhood characteristics | |||||
| Age at early childhood visit | 3.3 (0.4) | 3.3 (0.3) | 3.3 (0.3) | 3.3 (0.4) | 3.3 (0.5) |
| BMI z-score | 0.5 (1.0) | 0.4 (1.0) | 0.5 (1.0) | 0.4 (1.1) | 0.5 (1.0) |
| Waist circumference (cm) | 51.4 (3.7) | 51.4 (3.5) | 51.4 (3.5) | 51.2 (3.8) | 51.4 (4.0) |
| Sum of skinfolds (mm) | 16.7 (4.3) | 16.7 (4.2) | 17.1 (4.2) | 16.6 (4.7) | 16.5 (4.2) |
| Leptin (ng/mL) | 2.0 (2.0) | 1.9 (2.1) | 1.8 (1.7) | 2.1 (2.3) | 2.0 (1.8) |
| Adiponectin (µg/mL) | 22.3 (5.6) | 22.8 (5.2) | 22.1 (5.6) | 22.4 (5.4) | 22.0 (5.9) |
| Mid-childhood characteristics | |||||
| Age at mid-childhood visit | 8.0 (0.9) | 7.8 (0.7) | 7.9 (0.9) | 8.0 (0.8) | 8.1 (1.0) |
| BMI z-score | 0.4 (1.0) | 0.4 (1.0) | 0.4 (1.0) | 0.3 (1.1) | 0.5 (1.0) |
| Total fat mass (kg) | 7.5 (3.9) | 7.0 (3.2) | 7.4 (3.9) | 7.4 (4.1) | 8.0 (4.2) |
| Truncal fat mass (kg) | 2.5 (1.7) | 2.3 (1.4) | 2.5 (1.8) | 2.5 (1.7) | 2.7 (1.8) |
| Leptin (ng/mL) | 6.1 (7.5) | 5.6 (6.6) | 5.4 (6.5) | 5.8 (7.5) | 7.6 (8.7) |
| Adiponectin (µg/mL) | 15.6 (8.8) | 15.8 (8.9) | 14.4 (8.8) | 16.2 (8.5) | 15.5 (8.9) |
| HOMA-IR | 1.9 (1.8) | 1.6 (1.4) | 1.8 (1.4) | 1.8 (1.6) | 2.3 (2.5) |
Abbreviations: GCT: Glucose tolerance test; OGTT: Oral glucose tolerance test; IGT: Impaired glucose tolerance; GDM: Gestational diabetes mellitus
a
Based on address at the time of delivery
b
Maternal race/ethnicity is substituted in 10% of children whose race/ethnicity is missing