Autism Spectrum Disorder and Particulate Matter Air Pollution before, during, and after Pregnancy: A Nested Case–Control Analysis within the Nurses’ Health Study II Cohort

http://dx.doi.org/10.1289/ehp.1408133



Table 2. Control population characteristics by pregnancy PM2.5 quartile, Nurses’ Health Study II (n = 1,522 controls).
Characteristic Quartile [μg/m3 (range)]
1st
(5.24–12.3)
2nd
(12.4–14.5)
3rd
(14.6–16.7)
4th
(16.7–30.8)
IQR, interquartile range.
n 397 376 375 374
Male sex (n (%)] 208 (52) 203 (54) 192 (51) 190 (51)
Year of birth [median (IQR)] 1995 (5) 1994 (4) 1993 (4) 1992 (3)
Maternal age at birth (years) (mean ± SD) 34.3 ± 3.8 34.0 ± 3.8 33.5 ± 3.6 32.7 ± 3.6
Paternal age at birth (years) (mean ± SD) 37.4 ± 5.1 36.5 ± 4.9 36.1 ± 5.0 35.2 ± 4.5
Median census income ($1,000) [median (IQR)] 62 (31) 64 (28) 61 (26) 58 (24)
Median census house value ($1,000) [median (IQR)] 137 (107) 144 (104) 135 (96) 128 (82)
Birth weight (lbs) (mean ± SD) 7.2 ± 1.3 7.2 ± 1.2 7.1 ± 1.3 7.2 ± 1.3
Premature birth (n (%)]        
Yes 56 (14) 57 (15) 52 (14) 62 (17)
No 298 (75) 282 (75) 275 (73) 282 (75)
Missing 43 (11) 36 (10) 48 (13) 30 (8)
Gestational diabetes (n (%)]        
Yes 18 (5) 27 (7) 21 (6) 21 (6)
No 314 (79) 303 (81) 299 (80) 306 (82)
Missing 65 (16) 46 (12) 55 (15) 47 (13)
Preeclampsia (n (%)]        
Yes 12 (3) 9 (2) 8 (2) 14 (4)
No 320 (81) 321 (85) 312 (83) 313 (84)
Missing 65 (16) 46 (12) 55 (15) 47 (13)
Smoking during pregnancy (n (%)]        
Yes 17 (4) 17 (4) 21 (5) 17 (4)
No 323 (73) 313 (71) 308 (70) 315 (71)
Missing 102 (23) 112 (25) 112 (25) 110 (25)