摘要：A wide variety of environmental exposures have been linked to diabetes (
Dendup et al. 2018). Recently, a meta-analysis of five cohort studies reported a positive association between road traffic noise and type 2 diabetes (
Vienneau et al. 2019a). In a new report in
Environmental Health Perspectives, Thacher et al. (
2021) evaluated potential associations of long-term exposure to road, railway, and aircraft noise with type 2 diabetes in a nationwide cohort from Denmark. A major strength of this study is the inclusion of transportation noise at the most and least exposed residential façade. Health effects of transportation noise are believed to be mediated partly through sleep disturbance (
Héritier et al. 2018;
Münzel et al. 2017). As modeled day- and nighttime transportation noise are generally very strongly correlated with one another, it is impossible to disentangle effects of these exposures. However, many dwellings have quiet(er) façades, which could be where the bedroom would be located. Noise at the least exposed façade may better describe exposure during sleep, and studies including transportation noise at the most and least exposed façades could help to indicate whether daytime noise and noise during sleep are biologically relevant exposures for disease development.
Thacher et al. (
2021) observed a moderate correlation (Spearman
ρ
=
0.45
) between road traffic noise during the day, evening, and night (
L
den
) at the most and least exposed façade. This could be explained by several factors. Road traffic noise is mainly produced by the combustion engine and contact of wheels with the road and is transmitted by pressure waves. As noise waves spread out over the area, their energy decreases relatively quickly, and noise levels drop (
Davies et al. 2009). Moreover, dense and complex road networks and building configurations can affect noise levels because noise waves can be reflected and refracted by buildings and noise barriers.
In the study by Thacher et al. (
2021), associations of road traffic noise at the most and least exposed façades with diabetes were quite similar in the minimally adjusted model. However, after adjustment for socioeconomic status (SES), green space, and ambient fine particulate matter
PM
2.5
, associations of 10-y mean road traffic noise at the most exposed façade attenuated from
hazard ratio
(
HR
)
=
1.07
[95% confidence interval (CI): 1.07, 1.08
