Excess Absolute Risk: Translating Occupational Measures of Relative Risk to Expected Lifetime Risk Among the General...

Measures of relative risk obtained from occupational epidemiological studies present only part of a risk evaluation needed when conducting public health risk assessments (e.g., among members of the general population). Relative risk alone can often mask the true magnitude of effect and may significantly overestimate the actual risk at the population level, particularly if the background rate of the disease or condition is rare. It is recognized in public health risk assessment and epidemiology that significantly increased relative risk estimates observed in occupational epidemiological studies may not necessarily translate to a significant or excess public health risk. To estimate the expected risk of a given health endpoint among the general population, and thus effectively translate measures of relative risk observed in observational occupational studies, the focus must shift from relative risk models to those of absolute risk. This can be achieved through the epidemiological calculation of excess absolute risk. In this perspective report, the authors discuss the importance of using excess absolute risk calculations in public health risk assessments of rare diseases and demonstrate its application using the body of published occupational epidemiological studies on cosmetic talc miners and millers and mesothelioma risk. By calculating the excess absolute risk among the general population, the argument that cosmetic talc exposure is associated with an increased mesothelioma risk is disputed, and further demonstrates epidemiologically that there is no to negligible (if any) increased risk of mesothelioma from cosmetic talc exposures in the general public.