## Citation

Alderman, Beth W.; Barón, Anna E.; & Savitz, David A. (1993). Cautions in the Use of Antecedents as Surrogates for Confounders. American Journal of Epidemiology, 137(11), 1259-1272.

## Abstract

When lacking information on confounding variables, epidemiologists have used surrogates which are antecedents of both the exposures and confounders of interest. The usefulness of this strategy is explored in a series of scenarios for a prospective epidemiologic study wherein risk ratios relating antecedent to confounder, antecedent to exposure, and confounder to exposure were varied. Antecedent-adjusted, confounder-adjusted, and crude risk ratios were calculated and compared. The antecedent-adjusted risk ratio was useful, that is, was closer to the confounder-adjusted risk ratio than was the crude risk ratio, in 1,067 (49%) of 2,187 scenarios. The antecedent-adjusted risk ratio, the crude risk ratio, and the risk ratio relating confounder to exposure together predicted the usefulness of the antecedent (or any variable) as a confounder proxy. The antecedent was useful in 97% of scenarios wherein: 1) the antecedent-adjusted risk ratio was less than the crude risk ratio, and the risk ratio relating confounder to exposure was greater than 1.0, or 2) the antecedent-adjusted risk ratio was greater than the crude risk ratio, and the risk ratio relating confounder to exposure was less than 1.0. In the remaining scenarios, it was useful only 5% of the time.

## URL

http://dx.doi.org/10.1093/oxfordjournals.aje.a116628

Journal Article

1993

## Journal Title

American Journal of Epidemiology

## Series Title

Am J Epidemiol 1994 Sep 1;140(5):487.

## Author(s)

Alderman, Beth W.
Barón, Anna E.
Savitz, David A.