Long-term residential exposure to air pollution and Hodgkin lymphoma risk among adults in Denmark: a population-based case-control study.

The etiology of Hodgkin lymphoma (HL) is obscure. Research on air pollution and risk of HL provides inconsistent results. We aimed to investigate the association between long-term residential exposure to air pollution and risk of adult Hodgkin lymphoma in Denmark. We performed a nationwide register-based case–control study, including all (n = 2,681) Hodgkin lymphoma cases registered in the nationwide Danish Cancer Registry between 1989 and 2014. We randomly selected 8,853 age- and sex-matched controls from the entire Danish population using the Civil Registration System, and identified 20-year residential address history for all cases and controls. We modeled outdoor air pollution concentrations at all these addresses using the high-resolution multiscale air pollution model system DEHM/UBM/AirGIS. We used conditional logistic regression to estimate odds ratios adjusted for individual and neighborhood level sociodemographic variables. There was no association between 1, 5, 10, and 20 years’ time-weighted average exposure to fine particles (PM2.5), O3, SO2, NO2, or the PM2.5 constituents OC, NH4, NO3, and SO4 and risk of Hodgkin lymphoma. Residential exposure to ambient air pollution does not seem to increase the risk of developing Hodgkin lymphoma.