Use of sensitivity analysis to assess the effects on anti-hepatitis A virus antibodies of access to household water supply

Abstract

The objective of this study was to assess the impact of a possible unmeasured confounding variable in a previously published association between the effects of household water supply and positive results for hepatitis A serology. This was estimated using a path of integration between two methods of sensitivity analysis, called Rosenbaum's method and Greenland's external adjustment. The association between household water supply and positive results for hepatitis A (outcome) serology was insensitive to confounding unless the odds ratio for the association between the confounder and the outcome was 4. The integration of the two sensitivity analysis methods presented proved useful when assessing the effects of a potential unmeasured confounder. © 2007 Cambridge University Press.