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Table 2 Frequency of exposed case and control infants where the exposed group is defined as living in a census tract with an average metal level greater than or equal to the 90 th percentile a of average metal concentrations in tracts across the state

From: Association between arsenic, cadmium, manganese, and lead levels in private wells and birth defects prevalence in North Carolina: a semi-ecologic study

  Arsenic n (%)c Cadmium n (%)c Manganese n (%)c Lead n (%)c
1. Spina bifida (n = 218) 8 (3.7) 4 (1.8) 11 (5.0) 13 (6.0)
2. Anotia/microtia (n = 94) 3 (3.2) 3 (3.2) 6 (6.4) 5 (5.3)
3. Conotruncals (n = 435) 20 (4.6) 16 (3.7) 31 (7.1) 19 (4.4)
4. AVSD/ECD (n = 150) 8 (5.3) 5 (3.3) 10 (6.7) 5 (3.3)
5. HLHS (n = 142) 3 (2.1) 5 (3.5) 4 (2.8) 13 (9.2)
6. Cleft palate (n = 351) 17 (4.8) 15 (4.3) 18 (5.1) 20 (5.7)
7. Cleft lip ± CP (n = 516) 35 (6.8) 22 (4.3) 35 (6.8) 29 (5.6)
8. EA/TEF (n = 140) 9 (6.4) 6 (4.3) 7 (5.0) 8 (5.7)
9. Pyloric stenosis (n = 1,204) 73 (6.1) 20 (1.7) 63 (5.2) 59 (4.9)
10. Limb reduction (n = 255) 7 (2.7) 5 (2.0) 12 (4.7) 12 (4.7)
11. Gastroschisis (n = 215) 12 (5.6) 7 (3.3) 6 (2.8) 16 (7.4)
12. Hypospadias (n = 1,994) 92 (4.6) 94 (4.7) 107 (5.4) 122 (6.1)
Total cases (n = 5,534b) 283 (5.1) 196 (3.5) 303 (5.5) 310 (5.6)
Total controls (n = 668,381) 33,252 (5.0) 29,579 (4.4) 36,845 (5.5) 35,492 (5.3)
  1. aThe 90th percentile of census tract average levels was 2.54 ppb for arsenic, 1.82 ppb for cadmium, 139.69 ppb for manganese, and 7.28 ppb for lead.
  2. bNumber of case infants with a diagnosis of one or more of the twelve prioritized structural outcomes of interest.
  3. cPercent of each specific defect (Example: 8/218 = 3.7%).
  4. Abbreviations: ‘Conotruncals’ consists of a group of heart defects including common truncus, Tetralogy of Fallot, and transposition of the great arteries; Atrioventricular septal/Endocardial cushion defects (AVSD/ECD); Hypoplastic left heart syndrome (HLHS); Esophageal atresia also called tracheo-esophageal fistula (EA/TEF); ‘Limb reduction’ includes reduction defects of the upper and lower limbs.