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. 2014 Mar 21;122(7):651–660. doi: 10.1289/ehp.1306912

Table 3.

Characteristics of studies that focused on physical pipe integrity.a

Study Location Source water Treatment plant Distribution system Design Exposure Comparison exposure Outcome assessment Effect estimate (95% CI)
D’Argenio et al. 1995 Italy Not reported Not reported Presumed to be continuously operated; some chlorine residual; total coliforms, fecal coliforms, and fecal streptococci detected in affected pipe segment Cohort Pipeline with fecal contamination from cross-connections Pipeline with no fecal contamination Self-report RR = 2.67 (1.16, 6.11)b
Mohanty et al. 2002 India Surface water Conventional treatment with chlorination Intermittently operated; inadequate residual; total and fecal coliforms detected Ecological Unit increase in percentage of cast-iron pipes in service zone NA Self-report Regression coefficient, –0.42 (p = 0.10)
Yassin et al. 2006 Palestine Groundwater Chlorination Intermittently operated; inadequate residual; fecal contamination detected more often than at the source Cross-sectional Network > 1 year old Network ≤ 1 year old Self-report RR = 1.51 (0.80, 2.83)b
Abu Amr and Yassin 2008 Palestine Groundwater Chlorination Intermittently operated; inadequate residual; fecal contamination detected more often than at the source Cross-sectional Network > 1 year old Network ≤ 1 year old Self-report RR = 1.03 (0.68, 1.56)b
Nygård et al. 2004 Sweden Surface and groundwater Chlorination (for surface water only) Presumed to be continuously operated; low-level residual Ecological 10-m increase in pipe length per person in municipality NA Surveillance records IDR = 1.12 (1.08, 1.16)
Tinker et al. 2009 USA Not reported Not reported Presumed to be continuously operated; adequate residual Ecological ZIP code with long hydraulic residence time ZIP code with intermediate hydraulic residence time Emergency department records OR = 1.06 (1.04, 1.08)c
Abbreviations: IDR, incidence density ratio; NA, not applicable; OR, odds ratio; RR, relative risk. aResults not pooled. bCalculated from data reported in the study. cPooled from estimates for two utilities reported in the study.