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Table 5 Prevalences and prevalence odds ratios of the most common birth defects according to exposure to trihalomethanes in Taiwan 2001–2003.

From: Water disinfection by-products and the risk of specific birth defects: a population-based cross-sectional study in Taiwan

Outcomes   TTHM TTHM TTHM TTHM
   0–4 μg/L 5–9 μg/L 10–19 μg/L 20+ μg/L
   Reference Low Medium High
Any birth defect      
   N 2,148 978 368 421 381
   P (%) 0.540 0.540 0.660 0.510 0.510
   OR   1.00 1.23 0.95 0.94
   aOR (95% CI)   1.00 1.21 (1.07–1.36) 0.97 (0.86–1.08) 1.00 (0.89–1.13)
Anencephalus      
   N 43 19 9 2 13
   P (%) 0.011 0.010 0.016 0.002 0.017
   OR   1.00 1.54 0.23 1.65
   aOR (95% CI)   1.00 1.59 (0.72–3.52) 0.23 (0.05–1.01) 1.96 (0.94–4.07)
Hydrocephalus      
   N 118 58 24 19 17
   P (%) 0.030 0.032 0.043 0.023 0.023
   OR   1.00 1.35 0.72 0.71
   aOR (95% CI)   1.00 1.36 (0.85–2.20) 0.71 (0.42–1.20) 0.74 (0.43–1.28)
Ventricular septal defects      
   N 59 27 6 8 18
   P (%) 0.015 0.015 0.011 0.010 0.024
   OR   1.00 0.72 0.65 1.61
   aOR (95% CI)   1.00 0.74 (0.31–1.80) 0.65 (0.29–1.43) 1.81 (0.98–3.35)
Atrial septal defects      
   N 19 8 5 2 4
   P (%) 0.005 0.004 0.009 0.002 0.005
   OR   1.00 2.03 0.55 1.21
   aOR (95% CI)   1.00 2.15 (0.70–6.60) 0.53 (0.11–2.49) 1.33 (0.39–4.58)
Tetralogy of Fallot      
   N 24 13 6 3 2
   P (%) 0.006 0.007 0.011 0.004 0.003
   OR   1.00 1.50 0.51 0.37
   aOR (95% CI)   1.00 1.60 (0.61–4.23) 0.46 (0.13–1.61) 0.32 (0.07–1.47)
Cleft lip with/without palate      
   N 358 155 55 84 64
   P (%) 0.090 0.085 0.098 0.101 0.085
   OR   1.00 1.15 1.19 1.00
   aOR (95% CI)   1.00 1.15 (0.84–1.56) 1.20 (0.91–1.55) 0.98 (0.73–1.32)
Cleft palate      
   N 129 52 15 28 34
   P (%) 0.033 0.029 0.027 0.034 0.045
   OR   1.00 0.94 1.18 1.58
   aOR (95% CI)   1.00 0.94 (0.53–1.68) 1.17 (0.74–1.86) 1.56 (1.00–2.41)
Renal agenesis & dysgenesis      
   N 76 33 14 13 16
   P (%) 0.019 0.018 0.025 0.016 0.021
   OR   1.00 1.38 0.87 1.17
   aOR (95% CI)   1.00 1.33 (0.71–2.48) 0.92 (0.48–1.75) 1.27 (0.69–2.33)
Obstructive urinary tract defects      
   N 49 19 10 10 10
   P (%) 0.012 0.010 0.018 0.012 0.013
   OR   1.00 1.71 1.16 1.27
   aOR (95% CI)   1.00 1.65 (0.77–3.56) 1.24 (0.57–2.67) 1.44 (0.66–3.14)
Hypospadias      
   N 72 43 8 14 7
   P (%) 0.018 0.024 0.014 0.017 0.009
   OR   1.00 0.61 0.72 0.39
   aOR (95% CI)   1.00 0.59 (0.28–1.26) 0.76 (0.41–1.38) 0.47 (0.21–1.04)
Chromosome anomalies      
   N 364 174 72 67 51
   P (%) 0.092 0.096 0.129 0.081 0.068
   OR   1.00 1.35 0.85 0.71
   aOR (95% CI)   1.00 1.25 (0.95–1.65) 0.93 (0.70–1.24) 0.90 (0.66–1.24)
Down syndrome      
   N 166 73 36 30 27
   P (%) 0.042 0.040 0.064 0.036 0.036
   OR   1.00 1.60 0.90 0.89
   aOR (95% CI)   1.00 1.48 (0.99–2.21) 1.00 (0.65–1.54) 1.17 (0.74–1.83)
Trisomy 13      
   N 14 4 2 6 2
   P (%) 0.004 0.002 0.004 0.007 0.003
   OR   1.00 1.63 3.30 1.21
   aOR (95% CI)   1.00 1.56 (0.28–8.55) 3.36 (0.94–12.0) 1.12 (0.20–6.29)
Trisomy 18      
   N 54 23 12 13 6
   P (%) 0.014 0.013 0.021 0.016 0.008
   OR   1.00 1.70 1.24 0.63
   aOR (95% CI)   1.00 1.64 (0.81–3.30) 1.31 (0.66–2.59) 0.81 (0.33–2.02)
  1. *cOR: crude odds ratio; aOR: adjusted odds ratio. Logistic regression analysis adjusting for maternal age, plurality, and population density.*Estimates not given for the following rare outcomes: spinal bifida (n = 14) microcephalus (n = 9); endocardial cushion defects (n = 7); transposition of great vessels (n = 12); choanal atresia (n = 2); dysplasia of lung (n = 9); congenital cystic kidney (n = 24).
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