Table 6

Summary of the results from previous and present studies focusing on seven most common specific birth defect.

Sweden 2000 [14]
 Norway 2002 [12]
 California 2003(1) [11]
 California 2003(2) [11]
 England and Wales 2007 [13]
 Taiwan 2008
Type of study
 Cross-sectional, population-based
 Cross-sectional, population-based
 Case-control
 Case-control
 Cross-sectional, population-based
 Cross-sectional, population-based
Study Population
 115,801 births
 184,676 births
 539 controls
 481 conrols
 2,605,226 births
 396,409 births
No of birth Defects
 1,842
 5,764
 538
 265
 22,828
 2,148
Exposure
 Chlorine dioxide
 Chlorination, High color
 TTHMs 50–74 μg/l
 TTHMs 50–74 μg/l
 TTHMs >= 60 μg/l
 TTHMs >= 20 μg/l
Reference
 None
 No chlorination, Low color
 TTHMs 0 μg/l
 TTHMs 0 μg/l
 TTHMs <30 μg/l
 TTHMs 0–4 μg/l
Anencephalus
0.79 (0.15–4.23) (n = 46)
 0.55 (0.26–1.10) (n = 164)
 1.80 (0.76–4.40) (n = 89)
1.96 (0.94–4.07) (n = 43)
Hydorcephalus
 1.50 (0.30–7.30) (n = 36)
 2.70 (0.77–9.51) (n = 68)


0.74 (0.43–1.28) (n = 118)
Ventricular septal defects
1.81 (1.05–3.09) (n = 279)

1.43 (1.00–2.04) (n = 408)
 1.81 (0.98–3.35) (n = 59)
Atrial septal Defects
0.92 (0.24–1.50) (n = 73)


1.33 (0.39–4.58) (n = 19)
Cleft lip with/without palate
0.85 (0.53–1.38) (n = 248)
1.90 (0.81–4.50) (n = 117)
 0.94 (0.83–1.06) (n = 2,909)
 0.98 (0.73–1.32) (n = 358)
Cleft palate
1.07 (0.35–3.27) (n = 95)
1.00 (0.32–3.40) (n = 58)
 0.95 (0.76–1.10) (n = 1,929)
 1.56 (1.00–2.41) (n = 129)
Obstructive urinary tract defects
1.99 (0.66–5.96) (n = 102)


1.44 (0.66–3.14) (n = 49)

* Sweden 2000 [14]; California 2003(1): Shaw et. al. Study 1 [11]; California 2003(1): Shaw et. al. Study 2 [11]; Norway 2007 [12]; England and Wales 2007 [13]; Taiwan 2008: the present study.

Hwang et al. Environmental Health 2008 7:23   doi:10.1186/1476-069X-7-23

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