Residential exposure to traffic noise and risk for non-hodgkin lymphoma among adults

Exposure to traffic noise may result in stress and sleep disturbances, which have been associated with impairment of the immune system. People with weakened immune systems are known to have a higher risk for non-Hodgkin lymphoma (NHL). We aimed to determine whether traffic noise was associated with risk for NHL in a nationwide case-control study. We identified 2753 cases aged 30-84 years with a primary diagnosis of NHL in Denmark between 1992 and 2010. For each case we selected two random population controls, matched on sex and year of birth. Road traffic and railway noise were calculated, and airport noise was estimated for all present and historical residential addresses of cases and controls from 1987 to 2010. Associations between traffic noise and risk for NHL were estimated using conditional logistic regression, adjusted for disposable income, education, cohabiting status and comorbidity. We found that a 5-year time-weighted mean of road traffic noise above 65 dB was associated with an 18% higher risk for NHL (95% confidence interval (CI) 1.01-1.37) when compared to road traffic noise below 55 dB, whereas for exposure between 55 and 65 dB no association was found (odds ratio: 0.98; 95% CI: 0.88-1.08). In analyzes of NHL subtypes, we found no association between road traffic noise and risk for T-cell lymphoma, whereas increased risks for B-cell lymphoma and unspecified lymphomas were observed at exposures above 65 dB. In conclusion, our nationwide study may indicate that high exposure to traffic noise is associated with higher NHL risk.