Attributable Risk of Exposures Associated with Sexually Transmitted Disease

Attributable risk combines information on the prevalence of an exposure with a measure of the associated increment in risk, providing an estimate of the proportion of incident or prevalent disease that might be avoided by eliminating the exposure. Thus, attributable risk identifies exposures most productively targeted by public health interventions. Attributable risk can be defined as the ratio of average excess risk to average risk. As with other measures of association between exposure and disease computed from observational data, adjustment must be made for confounding factors. Estimates of attributable risk are highly variable. Nonetheless, attributable risk retains its usefulness as an approximate measure of the public health significance of exposures associated with acquisition of sexually transmitted disease, provided it is estimated and interpreted cautiously. AR = pr(E)(RR- l)/[pr(E)(RR- 1) + 1] (1) A more natural expression for AR involves the excess risk (ER)-that is, the difference in risk between the exposed and unexposed: risk of infection, and on a measure of the increment in risk of infection associated with exposure. The most commonly use