Relationship between long-term residential transportation noise characteristics and incident diabetes in the SAPALDIA study.

Abstract

Introduction: There is limited but suggestive evidence on the role of transportation noise exposure in the development of diabetes. Noise intermittency may be also relevant in relation to metabolic outcomes. We investigated the relationship between residential road, railway and aircraft noise levels including their intermittency, and incident diabetes in Swiss adults Methods: We followed 2,799 participants without diabetes, at the first follow-up (2001) of the Swiss Cohort Study on Air Pollution and Lung and Heart Diseases in Adults, over ten years, up to the second follow-up. Incident diabetes cases were identified from self-reported physician diagnosis, use of medication or glycated haemoglobin>6.5%. Noise exposures were derived from high-resolution Swiss noise models for 2001, assigning annual road, railway and aircraft 24-hour noise levels (Ldensource in dB(A)) and total intermittency ratio at night (i.e. % of contribution of individual events in the total noise level from all sources above a certain threshold, IRtotal,%) from the maximum exposure façade of participants’ residences. We applied mixed logistic regression and adjusted for potential confounders in models that included all noise exposure sources Results: There were 131 incident diabetes cases. Exposure means (SD) were 35.7 (8.8), 36.6 (9.1) and 54.5 (7.7) dB(A) for Ldenair, Ldenrail and Ldenroad, respectively, and 70.3% (19.5) for IRtotal. Ldenroad was significantly associated with incident diabetes (OR: 1.36; 95%CI: 1.01, 1.83) independently of Ldenair and Ldenrail, which showed positive but non-significant associations with incident diabetes. Associations with Ldenroad were strongest at lower IRtotal (Pinteraction=0.031). The same intermittency interaction pattern was observed for day- and night-time road noise levels and for noise assigned at the bedroom façade Conclusion: Constant noise levels may be more relevant than intermittency, a potential effect modifier, in the development of diabetes