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Table 5 Crude and adjusted* odds ratio of preterm birth comparing above versus below the median of environmental exposure stratified by census tract-level socioeconomic status (SES) in Fresno County, 2009–2012 (N = 53,843)

From: Environmental pollution and social factors as contributors to preterm birth in Fresno County

Environmental Exposure

Low SES

High SES

< 37 weeks

≥37 weeks

  

< 37 weeks

≥37 weeks

  

N (%)

N (%)

cOR (95% CI)

aOR* (95% CI)

N (%)

N (%)

cOR (95% CI)

aOR* (95% CI)

Sample

2455

24,998

  

2105

24,285

  

Exposures Score

    < 50th

924 (37.6)

10,360 (41.4)

Reference

Reference

1172 (55.7)

14,101 (58.1)

Reference

Reference

    ≥ 50th

1531 (62.4)

14,638 (58.6)

1.16 (1.07, 1.25)

1.16 (1.06, 1.25)

933 (44.3)

10,184 (41.9)

1.09 (1.00, 1.19)

1.07 (0.98, 1.17)

 Ozone

    < 50th

1481 (60.4)

15,063 (60.3)

Reference

Reference

777 (36.9)

8752 (36.0)

Reference

Reference

    ≥ 50th

974 (39.7)

9935 (39.7)

1.00 (0.92, 1.08)

1.00 (0.92, 1.08)

1295 (61.5)

14,916 (61.4)

0.98 (0.90, 1.07)

0.99 (0.90, 1.08)

 Pesticides

    < 50th

1019 (41.5)

9872 (39.5)

Reference

Reference

1244 (59.1)

14,691 (60.5)

Reference

Reference

    ≥ 50th

1436 (58.5)

15,126 (60.5)

0.93 (0.86, 1.00)

0.92 (0.85, 1.00)

861 (40.9)

9594 (39.5)

1.05 (0.97, 1.15)

1.05 (0.97, 1.15)

 PM2.5

    < 50th

592 (24.1)

6434 (25.7)

Reference

Reference

1425 (67.7)

17,259 (71.1)

Reference

Reference

    ≥ 50th

1736 (70.7)

17,286 (69.2)

1.08 (0.99, 1.19)

1.07 (0.98, 1.18)

650 (30.9)

6492 (26.7)

1.19 (1.09, 1.31)

1.15 (1.05, 1.26)

 Diesel PM

    < 50th

1096 (44.6)

12,166 (48.7)

Reference

Reference

1051 (49.9)

12,587 (51.8)

Reference

Reference

    ≥ 50th

1359 (55.4)

12,832 (51.3)

1.16 (1.07, 1.25)

1.16 (1.07, 1.25)

1054 (50.1)

11,698 (48.2)

1.07 (0.98, 1.17)

1.04 (0.96, 1.14)

 Toxic Release

    < 50th

735 (29.9)

8106 (32.4)

Reference

Reference

1315 (62.5)

16,391 (67.5)

Reference

Reference

    ≥ 50th

1720 (70.1)

16,892 (67.6)

1.11 (1.02, 1.21)

1.11 (1.02, 1.22)

790 (37.5)

7894 (32.5)

1.22 (1.12, 1.34)

1.18 (1.08, 1.29)

 Traffic

    < 50th

1240 (50.5)

13,288 (52.9)

Reference

Reference

972 (46.2)

11,579 (47.7)

Reference

Reference

    ≥ 50th

1215 (49.5)

11,770 (47.1)

1.09 (1.01, 1.18)

1.09 (1.01, 1.18)

1133 (53.8)

12,706 (52.3)

1.05 (0.97, 1.15)

1.03 (0.95, 1.13)

 Drinking Water

    < 50th

143 (5.8)

1863 (7.5)

Reference

Reference

402 (19.1)

4713 (19.4)

Reference

Reference

    ≥ 50th

2312 (94.2)

23,135 (92.6)

1.27 (1.08, 1.51)

1.29 (1.09, 1.52)

1703 (80.90

19,572 (80.6)

1.02 (0.91, 1.14)

1.00 (0.90, 1.12)

  Arsenic

    < 50th

234 (9.5)

2467 (9.9)

Reference

Reference

493 (23.4)

6230 (25.7)

Reference

Reference

    ≥ 50th

2221 (90.5)

22,531 (90.1)

1.04 (0.91, 1.19)

1.01 (0.88, 1.16)

1612 (76.6)

18,055 (74.4)

1.12 (1.01, 1.24)

1.09 (0.99, 1.21)

  Cadmium

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

  1,2-Dibromo-3-chloropropane (DBCP)

    < 50th

979 (39.9)

10,100 (40.4)

Reference

Reference

604 (28.7)

6924 (28.5)

Reference

Reference

    ≥ 50th

1476 (60.1)

14,898 (59.5)

1.02 (0.94, 1.11)

1.02 (0.94, 1.10)

1472 (69.9)

16,834 (69.3)

1.00 (0.91, 1.10)

1.00 (0.91, 1.10)

  Hexavalent Chromium

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2147 (87.5)

21,281 (85.1)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

  Lead

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

  Nitrate

    < 50th

1019 (41.5)

10,330 (41.3)

Reference

Reference

1226 (58.2)

14,410 (59.3)

Reference

Reference

    ≥ 50th

1436 (58.5)

14,668 (58.7)

0.99 (0.92, 1.08)

0.99 (0.92, 1.07)

879 (41.8)

9875 (40.7)

1.04 (0.96, 1.14)

1.03 (0.94, 1.12)

  Perchlorate

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

  Trichloroethylene (TCE)

    < 50th

1036 (42.2)

11,114 (44.5)

Reference

Reference

1182 (56.2)

13,607 (56.0)

Reference

Reference

    ≥ 50th

1419 (57.8)

13,884 (55.5)

1.09 (1.00, 1.18)

1.07 (1.00, 1.17)

923 (43.9)

10,678 (44.0)

1.00 (0.91, 1.09)

0.99 (0.91, 1.08)

  Trihalomethane (THM)

    < 50th

1145 (46.6)

11,838 (47.4)

Reference

Reference

859 (40.8)

9593 (39.5)

Reference

Reference

    ≥ 50th

1310 (53.4)

13,160 (52.6)

1.03 (0.95, 1.11)

1.01 (0.93, 1.09)

1246 (59.2)

14,692 (60.5)

0.95 (0.87, 1.04)

0.96 (0.88, 1.04)

  Uranium

    < 50th

487 (19.8)

5535 (22.1)

Reference

Reference

294 (14.0)

3801 (15.7)

Reference

Reference

    ≥ 50th

1968 (80.2)

19,463 (77.9)

1.15 (1.04, 1.27)

1.14 (1.03, 1.25)

1679 (79.8)

18,9488 (78.0)

1.13 (1.00, 1.28)

1.12 (0.99, 1.27)

  Maximum Contaminant Level (MCL)Violations

    < 50th

1030 (42.0)

10,577 (42.3)

Reference

Reference

1207 (57.3)

13,998 (57.6)

Reference

Reference

    ≥ 50th

1425 (58.0)

14,4211 (57.7)

1.01 (0.94, 1.10)

1.00 (0.92, 1.09)

898 (42.7)

10,287 (42.4)

1.01 (0.93, 1.10)

1.00 (0.92, 1.09)

  Total coliform rule (TCR) Violations

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

Environmental Effects Score

    < 50th

1036 (42.2)

10,073 (40.3)

Reference

Reference

1254 (59.6)

14,381 (59.2)

Reference

Reference

    ≥ 50th

1419 (57.8)

14,925 (59.7)

0.93 (0.86, 1.01)

0.92 (0.85, 1.00)

851 (40.4)

9904 (40.8)

0.99 (0.90, 1.08)

0.98 (0.89, 1.07)

 Cleanup Sites

    < 50th

1168 (47.6)

11,805 (47.2)

Reference

Reference

1139 (54.1)

12,799 (52.7)

Reference

Reference

    ≥ 50th

1287 (52.4)

13,193 (52.8)

0.99 (0.91, 1.07)

0.97 (0.90, 1.05)

966 (45.9)

11,486 (47.3)

0.95 (0.87, 1.03)

0.95 (0.87, 1.04)

 Groundwater Threats

    < 50th

973 (39.6)

9545 (38.2)

Reference

Reference

1290 (61.3)

15,062 (62.0)

Reference

Reference

    ≥ 50th

1482 (60.4)

15,453 (61.8)

0.95 (0.87, 1.03)

0.93 (0.86, 1.01)

815 (38.7)

9223 (38.)

1.03 (0.94, 1.12)

1.02 (0.94, 1.12)

 Hazardous Waste

    < 50th

1023 (41.7)

10,195 (40.8)

Reference

Reference

1240 (58.9)

14,430 (59.4)

Reference

Reference

    ≥ 50th

1432 (58.3)

14,803 (59.2)

0.97 (0.89, 1.05)

0.98 (0.90, 1.06)

865 (41.1)

9855 (40.6)

1.02 (0.93, 1.11)

0.99 (0.91, 1.09)

 Impaired Water Bodies

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

 Solid Waste

    < 50th

0 (0.0)

0 (0.0)

Reference

Reference

0 (0.0)

0 (0.0)

Reference

Reference

    ≥ 50th

2455 (100.0)

24,998 (100.0)

NC

NC

2105 (100.0)

24,285 (100.0)

NC

NC

Pollution Burden Score

    < 50th

827 (33.7)

8615 (35.5)

Reference

Reference

1380 (65.6)

16,068 (66.2)

Reference

Reference

    ≥ 50th

1628 (66.3)

16,383 (65.5)

1.03 (0.95, 1.12)

1.04 (0.96, 1.13)

725 (34.4)

8217 (33.8)

1.03 (0.94, 1.12)

1.03 (0.93, 1.11)

  1. NC Not Calculated, cOR crude odds ratio, aOR adjusted odds ratio
  2. *Adjusted for maternal race/ethnicity, age, education, payment for delivery
  3. SES defined as “Socioeconomic Factors” score from the CalEnviroScreen, which includes the following variables derived from the US Census American Community Survey: educational attainment, linguistic isolation (households where no one over 14 years of age speaks English very well), poverty and unemployment
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