Table A23.
Summary of findings table for the association between rail traffic noise exposure and the prevalence of ischaemic heart disease.
| Question | Does Exposure to Rail Traffic Noise Increase the Risk of IHD | ||||
|---|---|---|---|---|---|
| People | Adult population (men and women) | ||||
| Setting | Residential setting: people living several cities in Europe | ||||
| Outcome | The prevalence of IHD | ||||
| Summary of findings | RR per 10 dB increase in road traffic noise level (LDEN) | 1.18 (95% CI: 0.82–1.68) per 10 dB | |||
| Number of participants (# studies) | 13,241 (4) | ||||
| Number of cases | 283 | ||||
| Rating | Adjustment to rating | ||||
| Quality assessment | Starting rating | 4 cross-sectional studies | 2 (low) # | ||
| Factors decreasing confidence | Risk of bias | Serious a | Downgrading | ||
| Inconsistency | Serious b | Downgrading | |||
| Indirectness | None c | No downgrading | |||
| Imprecision | Minor d | No downgrading | |||
| Publication bias | NA e | No downgrading | |||
| Factors increasing confidence | Strength of association | Large, but non-significant 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 | 0 (very low) | ||||
# Since only cross-sectional studies were available, we started with a grading of “low” (2); a Response rates were in two of the four studies below 60%. In all studies, IHD was ascertained by means of a questionnaire only; b Results across studies differed in the magnitude and direction of effect estimates (see Figure 5.7 of the complete review). This was confirmed by the results of the heterogeneity analyses, indicating “moderate” heterogeneity (I2residual = 57.4%); c The studies assessed population, exposure and outcome of interest; d We considered the results to be less precise: the 95% CI contained values > 1.25; however, we considered the sample size to be sufficiently large; 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 rail 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 1.18 per 10 dB. The noise range of the studies under evaluation was 30–80 dB. This means that if rail traffic noise level increases from 30 to 80 dB, the RR = 2.29; g We were not able to draw any conclusions whether possible residual confounders or biases would reduce our effect estimate.