Define attributable risk and population attributable risk.

• A. Attributable risk is the excess risk among the exposed: Re - Ru; PAR is the proportion of disease in the population attributable to the exposure
• B. Attributable risk is the risk in the unexposed; PAR is the total risk in the population
• C. Attributable risk equals RR minus 1; PAR equals Pe*(RR-1)
• D. Attributable risk is the difference in incidence between unexposed and exposed; PAR is the proportion prevented by exposure

Answer: (A)