Table A29.
Summary of findings table for the association between road traffic noise exposure and mortality due to ischaemic heart disease: cohort and case-control studies.
| Question | Does Exposure to Road Traffic Noise Increase the Risk of IHD | |||
|---|---|---|---|---|
| People | Adult population (men and women) | |||
| Setting | Residential setting: people living several cities in Europe | |||
| Outcome | Mortality due to IHD | |||
| Summary of findings | RR per 10 dB increase in road traffic noise level (LDEN) | 1.05 (95% CI: 0.97–1.13) per 10 dB | ||
| Number of participants (# studies) | 532,268 (3) | |||
| Number of cases | 6884 | |||
| Rating | Adjustment to rating | |||
| Quality assessment | Starting rating | 1 cohort studies, 2 case-control studies | 4 (high) # | |
| Factors decreasing confidence | Risk of bias | Limited a | Downgrading | |
| Inconsistency | Limited b | No downgrading | ||
| Indirectness | None c | No downgrading | ||
| Imprecision | None d | No downgrading | ||
| Publication bias | NA e | No downgrading | ||
| Factors increasing confidence | Strength of association | Small f | No upgrading | |
| Exposure-response gradient | Evidence of a non-significant exposure-response gradient f | No upgrading | ||
| Possible confounding | No conclusions can be drawn g | No upgrading | ||
| Overall judgement of quality of evidence | 3 (moderate) | |||
# Since cohort and case-control studies were available, we started with a grading of “high” (4); a For the largest of the three studies, there was a possible risk of bias since there were worries with regard to exposure assessment, and one was not able to adjust for smoking; b Results across studies differed in the magnitude and direction of effect estimates (see Figure 5.5 of the complete review). This was not confirmed by the heterogeneity analyses, demonstrating “low” heterogeneity (I2residual = 34.9%); c The study assessed population, exposure and outcome of interest; d We considered the results to be precise: Both the number of participants and cases were much larger than 200. The 95% CI did not contain values below 0.75 or above 1.25; e Due to the low number of available effect estimates, it was not possible to test for publication bias or small study bias; f Most studies found that the risk of IHD increased when road traffic noise level increased (RR per 10 dB > 1). There was evidence of a non-significant exposure-response gradient: After aggregating the results of the evaluated studies, we found a non-significant effect size of 1.05 per 10 dB. The noise range of the studies under evaluation was 42–70 dB; g We were not able to draw any conclusions whether possible residual confounders or biases would reduce our effect estimate.