Population attributable risk is defined as the difference between-

.population attributable risk is the incidence of the disease or death in the total population minus the incidence of disease or death among those who were not exposed to the suspected casual factor..this concept is useful in that it provides an estimate of the amount by which the disease could be reduced in that population if the suspected factor was eliminated or modified. ref:park&;s textbook,22 nd ed,pg 75