Table A14.
Summary of findings table for the association between aircraft noise exposure and the prevalence of hypertension.
| Question | Does Exposure to Aircraft Noise Increase the Risk of Hypertension | |||
|---|---|---|---|---|
| People | Adult population (men and women) | |||
| Setting | Residential setting: people living in cities (general population) located around airports in Europe and Japan | |||
| Outcome | The prevalence of hypertension | |||
| Summary of findings | RR per 10 dB increase in aircraft noise level (LDEN) | 1.05 (95% CI: 0.95–1.17) per 10 dB | ||
| Number of participants (# evaluated studies) | 60,121 (9) | |||
| Number of cases | 9487 | |||
| Rating | Adjustment to rating | |||
| Quality assessment | Starting rating | 9 cross-sectional studies a | 2 (low) | |
| Factors decreasing confidence | Risk of bias | Serious b | Downgrading | |
| Inconsistency | Serious c | Downgrading | ||
| Indirectness | None d | No downgrading | ||
| Imprecision | None e | No downgrading | ||
| Publication bias | None f | No downgrading | ||
| Factors increasing confidence | Strength of association | Small g | No upgrading | |
| Exposure-response gradient | Non-significant exposure-response gradient g | Upgrading | ||
| Possible confounding | No serious bias h | Upgrading | ||
| Overall judgement of quality of evidence | 0 (low) | |||
a Since only cross-sectional studies were available, we started with a grading of “low” (2); b Methods used to select the population: In six studies, the participants were randomly selected, taking into account aircraft noise exposure; three studies were originally not designed to investigate the impact of aircraft noise exposure, but still participants were randomly selected. In six studies, participants were probably not aware of the fact that they participated in a study investigating the impact of noise; for three studies, this was unclear. For one study, it was likely that participants were aware of the fact that they participated in a study investigating the impact of noise. In six studies, response rates were below 60%; for two studies, the response rate was unclear and only in one study response rate was higher than 60%; c Results across studies differed in magnitude and direction of effect estimates (see Figure 4.1 of the complete review). This was confirmed by the results of the heterogeneity analyses, demonstrating moderate heterogeneity (I2residual = 72.1%); d The studies assessed population, exposure, and outcome of interest; e We considered the results to be precise, since the number of participants and the number of cases was large enough. The 95% confidence interval was sufficiently narrow; f There was little reason to believe that there is major publication bias or small study bias (see also Figure 4.2). The Egger test did not provide evidence for small-study effects; g Most studies found that the risk of hypertension increased when aircraft 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 35–75 dB. This means that if air traffic noise level increases from 35 to 75 dB, the RR = 1.22. We found indications for an effect of exposure duration: The effect estimates turned out to be larger for the sample that lived for a longer period in the same house; h We did not find evidence that suggests that possible residual confounders or biases would reduce our effect estimate.