Mortality surveillance strategies and study results for a cohort of U.S. petroleum company men and women

This petroleum company has surveillance programs to study overall mortality patterns and trends among workers in North America. This is possible because of the availability of public data systems in the U.S. and Canada that allow a complete accounting of deaths among former and current employees and stable population death rates for comparisons. We recently completed a cohort mortality study of almost 177,000 U.S.-based men and women who contributed close to three million person-years of observation during a 22-year period (1979-2000). The cohort is unique in its high proportion of relatively more recent employees; this allows us to study mortality among employees with workplace conditions closer to those of the present day. The cohort also offers the opportunity to study 50,000 women in the petroleum industry. We will provide an overview of results for men and women and discuss how interpretation takes into account the strengths of this methodology and its limitations (such as the healthy worker effect). We will also discuss the uses of information gained from such studies and the importance of communicating findings to employees and others.