Occupational Cohort Studies in North America: Opportunities for Collaboration with OMEGA-NET partners

Abstract

BACKGROUND AND AIM: While establishing and maintaining occupational cohorts is resource-intensive, findings from these studies often provide the basis for evidence-based policy decisions. The global harmonization of occupational cohort studies, as proposed by the OMEGA-NET project, will increase their value. This presentation provides an overview of selected U.S. and Canadian occupational cohorts, highlighting international collaborations. We will also discuss characteristics of successful international collaborations in progress, and some of the challenges. METHODS: The National Institute for Occupational Safety and Health has over 70 industrial cohorts representing a range of exposures including metals, organic compounds, particles and physical agents. Inclusion criteria vary and cohort sizes range from a few hundred to over 100,000. Many cohorts have detailed exposure histories and job-exposure matrices. In the U.S., cause of death and cancer incidence are determined by linkage with the U.S. National Death Index and state-based cancer registries, respectively. In Canada, cohort studies focused on specific industries (e.g. mining or forestry) or very large multi-industry cohorts have been conducted using national mortality and tumor registry or provincial medical record linkages. RESULTS:Several North American occupational cohorts currently participate in international pooled studies, including the International Nuclear Workers Study (INWORKS; n=308,000); the Pooled Uranium Miner Analysis (PUMA; n=120,000); and A Consortium of Agricultural Cohorts (AGRICOH; 22 cohorts). Potential cohorts that could involve global collaboration include workers exposed to engineered nanomaterials, firefighters, flight crew, and styrene. Challenges of pooling data include privacy concerns, and institutional restrictions on data sharing. Benefits of encouraging OMEGA-NET users to include North American occupational cohorts in pooled studies include the increased ability to investigate effect heterogeneity due to diversity of participants. CONCLUSIONS:Occupational exposures are among the most important modifiable risk factors in public health. The OMEGA-NET activity promotes collaborative and harmonized research that will enable evidence-based decision-making to reduce occupational disease. KEYWORDS: Cancer, International Pooled Studies, Occupational