Table 1.
Systematic Review Search Terms. a
Figure 1.
Systematic review flow chart.
Table 2.
Selected Characteristics of Included Studies.
Table 3.
Summary of EC Study Exposure and Outcome Measurements.
Table 4.
Summary of FC Study Exposure and Outcome Measurements.
Table 5.
EC Study Results.
Table 6.
FC Study Results.
Figure 2.
Forest plot for all included studies.
Figure 3.
Funnel plot for all included studies (EC and FC studies).
Studies are plotted relative to size (SE of Log RR), and reported log relative risk (Log RR); studies higher on the vertical axis are larger, and studies further to the right have larger RRs. The solid vertical line is the log of the summary RR for all studies, and the dotted lines are “pseudo 95% confidence intervals” for the summary measure. The absence of smaller studies with small or null RRs (lower left region of the plot) creates plot asymmetry, and provides evidence of possible publication bias.
Figure 4.
Forest plot for all studies stratified by indicator organism.
Top panel, EC: Escherichia coli; Bottom panel, FC: thermotolerant (“fecal”) coliforms.
Figure 5.
Studies are plotted relative to size (SE of Log RR), and reported log relative risk (Log RR); studies higher on the vertical axis are larger, and studies further to the right have larger RRs. The solid vertical line is the log of the summary RR for all studies, and the dotted lines are “pseudo 95% confidence intervals” for the summary measure. Studies on this plot are generally symmetrical, with the exception of one small study with a large RR, providing minimal evidence of publication bias.
Figure 6.
Funnel plot for all FC studies.
Studies are plotted relative to size (SE of Log RR), and reported log relative risk (Log RR); studies higher on the vertical axis are larger, and studies further to the right have larger RRs. The solid vertical line is the log of the summary RR for all studies, and the dotted lines are “pseudo 95% confidence intervals” for the summary measure. The absence of smaller studies with small or null RRs (lower left region of the plot) creates plot asymmetry, and provides evidence of possible publication bias.
Figure 7.
Forest plot for two studies with extractable data at multiple thresholds.
Data were pooled across the two studies at the 1 EC/100 ml threshold (top panel), 10 EC/100 ml threshold (middle panel), and 100 EC/100 ml threshold (bottom panel). EC: Escherichia coli.