Table 1.
Characteristics of Study Population (Births in at Least One Pollutant Specific Analysis), by Birth Category. New Jersey Air Pollution and Adverse Birth Outcomes Study. 1999-2003 (N=199,221 Term Births).
| REFERENCE BIRTHS |
SGA* BIRTHS |
VSGA† BIRTHS |
||||||
|---|---|---|---|---|---|---|---|---|
| CHARACTERISTIC | N | % | N | % | p-value χ2 test (SGA vs. Reference) |
N | % | p-value χ2 test (VSGA vs. Reference) |
| Sample Size | 178,198 | 90 | 16,340 | 8 | 4,683 | 2 | ||
|
| ||||||||
| Maternal Age (years) | <0.01 | <0.01 | ||||||
| <20 | 14,223 | 8 | 2,007 | 13 | 597 | 13 | ||
| 20-24 | 34,420 | 19 | 3,769 | 23 | 1,070 | 23 | ||
| 25-29 | 45,010 | 25 | 3,947 | 24 | 1,103 | 24 | ||
| 30-34 | 51,615 | 29 | 3,960 | 24 | 1,096 | 23 | ||
| ≥35 | 32,930 | 19 | 2,657 | 16 | 817 | 17 | ||
|
| ||||||||
| Prenatal Care Initiation | <0.01 | <0.01 | ||||||
| 1st Trimester | 141,153 | 79 | 12,208 | 75 | 3,387 | 72 | ||
| 2nd Trimester | 29,605 | 17 | 3,218 | 20 | 992 | 21 | ||
| 3rd Trimester | 7,440 | 4 | 914 | 5 | 304 | 7 | ||
|
| ||||||||
| Maternal Smoking during pregnancy | 14,350 | 8 | 2,384 | 15 | <0.01 | 893 | 19 | <0.01 |
|
| ||||||||
|
Maternal Alcohol Use during
pregnancy |
1,867 | 1 | 297 | 2 | <0.01 | 121 | 3 | <0.01 |
|
| ||||||||
| Maternal Drug Use during pregnancy | 2,419 | 1 | 553 | 3 | <0.01 | 305 | 7 | <0.01 |
|
| ||||||||
| Maternal Marital Status | <0.01 | <0.01 | ||||||
| Single | 63,534 | 36 | 7,348 | 45 | 2,361 | 51 | ||
| Married | 112,997 | 63 | 8,817 | 54 | 2,265 | 48 | ||
| Separated, Divorced, Widowed | 1,667 | 1 | 175 | 1 | 57 | 1 | ||
|
| ||||||||
| Maternal Education | <0.01 | <0.01 | ||||||
| < High School | 30,160 | 17 | 3,589 | 22 | 1,140 | 24 | ||
| High School Graduate | 57,743 | 32 | 5,548 | 34 | 1,741 | 37 | ||
| Some College or More | 90,295 | 51 | 7,203 | 44 | 1,802 | 39 | ||
| Maternal Race | <0.01 | <0.01 | ||||||
| White (non-Hispanic) | 84,747 | 47 | 7,478 | 46 | 1,930 | 41 | ||
| African American (non-Hispanic) | 38,978 | 22 | 3,952 | 24 | 1,363 | 29 | ||
| Hispanic | 54,473 | 31 | 4,910 | 30 | 1,390 | 30 | ||
|
| ||||||||
| Pregnancy Complications | ||||||||
| Pre-pregnancy Hypertension | 1,990 | 1 | 256 | 2 | <0.01 | 139 | 3 | <0.01 |
| Gestational Hypertension | 10,028 | 6 | 1,452 | 9 | <0.01 | 788 | 17 | <0.01 |
| Pre-eclampsia | 3,742 | 2 | 688 | 4 | <0.01 | 491 | 10 | <0.01 |
| Eclampsia | 142 | 0 | 15 | 0 | 0.60 | 21 | 0 | <0.01 |
| Diabetes Mellitus (Type I and II) | 1,491 | 1 | 109 | 1 | 0.02 | 47 | 1 | 0.22 |
| Gestational Diabetes | 8,416 | 5 | 574 | 4 | <0.01 | 198 | 4 | 0.11 |
| Placenta Previa | 766 | 0 | 92 | 1 | 0.01 | 53 | 1 | <0.01 |
| Fetal Distress | 9,740 | 5 | 1,336 | 8 | <0.01 | 600 | 13 | <0.01 |
| Placental Abruption | 839 | 0 | 177 | 1 | <0.01 | 136 | 3 | <0.01 |
| Premature Rupture of Membrane | 5,757 | 3 | 797 | 5 | <0.01 | 369 | 8 | <0.01 |
|
| ||||||||
|
Percentage of population(≥ 25 years)
in maternal residence census tract with < 12 years of education |
<0.01 | <0.01 | ||||||
| <15 | 68,143 | 38 | 5,847 | 36 | 1,564 | 33 | ||
| 15 to <25 | 39,325 | 22 | 3,686 | 23 | 1,015 | 22 | ||
| 25 to <40 | 41,354 | 23 | 3,935 | 24 | 1,236 | 26 | ||
| ≥40 | 29,376 | 17 | 2,872 | 17 | 868 | 19 | ||
|
| ||||||||
|
Percentage of population(≥ 25 years)
in maternal residence census tract with at least 4 years of college |
<0.01 | <0.01 | ||||||
| <15 | 62,346 | 35 | 6,021 | 37 | 1,836 | 39 | ||
| 15 to <25 | 41,095 | 23 | 3,846 | 24 | 1,111 | 24 | ||
| 25 to <40 | 35,765 | 20 | 3,123 | 19 | 871 | 19 | ||
| ≥40 | 38,992 | 22 | 3,350 | 20 | 865 | 18 | ||
|
Percentage of population in maternal
residence census tract below federally defined poverty line |
<0.01 | <0.01 | ||||||
| <5 | 67,854 | 38 | 5,762 | 35 | 1,519 | 32 | ||
| 5 to <10 | 35,328 | 20 | 3,334 | 21 | 929 | 20 | ||
| 10 to <20 | 40,086 | 22 | 3,759 | 23 | 1,110 | 24 | ||
| ≥20 | 34,930 | 20 | 3,485 | 21 | 1,125 | 24 | ||
*
SGA = “Small for gestational age” defined as a fetal growth ratio (i.e. newborn’s birth weight divided by median birth weight of corresponding gestational age/gender/race specific stratum) ≥0.75 and <0.85.
†
VSGA = “Very small for gestational age” defined as fetal growth ratio <0.75.