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Table 1 Characteristics at study entry for women residing in North Carolina who delivered at least two singleton neonates, 2002-2006

From: A longitudinal study of exposure to fine particulate matter during pregnancy, small-for-gestational age births, and birthweight percentile for gestational age in a statewide birth cohort

 

Non-Hispanic black

(n = 13,797)

n (%)a

Non-Hispanic white

(n = 39,617)

n (%)a

p-valueb

Infants born SGA

2940 (21.3)

2305 (5.82)

< 0.001

Mean birthweight percentile for gestational age

37.3 (26.5)

51.3 (27.9)

 

Age of mother, years

  

< 0.001

  < 20

4372 (31.7)

4993 (12.6)

 

 20-24

5333 (38.6)

9877 (25.0)

 

 25-29

2442 (17.7)

12,015 (30.3)

 

 30-34

1248 (9.05)

10,078 (25.4)

 

 35-39

373 (2.70)

2514 (6.32)

 

 40-44

31 (0.22)

130 (0.33)

 

Educational level, years

  

< 0.001

 No high school diploma

4308 (31.2)

5352 (13.5)

 

 High school diploma

7727 (56.0)

17,281 (43.6)

 

 College diploma

1762 (12.8)

16,894 (42.9)

 

Not married

10,052 (72.9)

8072 (20.4)

< 0.001

Birth order

  

< 0.001

 1

7865 (57.0)

27,584 (69.6)

 

 2

4092 (29.7)

8921 (22.5)

 

 3

1794 (13.0)

3053 (7.71)

 

  > 4

46 (0.33)

59 (0.15)

 

Smoker

1412 (10.2)

5491 (13.9)

< 0.001

Median household income (census tract)

$35,239 (13,115)

$46,485 (16,621)

< 0.001

  1. aThe cell count and percentage are presented except in the cases of birthweight percentile for gestational age and median household income, where the mean and standard deviation are provided
  2. bThe chi-square test was used to test for differences by race group for categorical variables. The Kruskal-Wallis rank sum test was used birthweight percentile for gestational age and census tract-level median household income