Table A20.
Summary of findings table for the association between rail traffic noise exposure and the incidence of hypertension.
| Question | Does Exposure to Rail Traffic Noise Increase the Risk of Hypertension | |||
|---|---|---|---|---|
| People | Adult population (men and women, 50–64 years) | |||
| Setting | Residential setting: people living in Aarhus or Copenhagen (Denmark) | |||
| Outcome | The incidence of hypertension | |||
| Summary of findings | RR per 10 dB increase in road traffic noise level (LDEN) | 0.96 (0.88–1.04) per 10 dB | ||
| Number of participants (# studies) | 7249 (1) | |||
| Number of cases | 3145 | |||
| Rating | Adjustment to rating | |||
| Quality assessment | Starting rating | 1 cohort study # | 4 (high) | |
| Factors decreasing confidence | Risk of bias | Serious limitations a | Downgrading | |
| Inconsistency | NA 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 | NA f | No upgrading | |
| Exposure-response gradient | No evidence of an exposure-response gradient f | No upgrading | ||
| Possible confounding | None | No upgrading | ||
| Overall judgement of quality of evidence | 2 (low) g | |||
# Since a cohort study was available, we started with a grading of “high” (4); a Participants were people participating in the DCH cohort. For this cohort, people living in Aarhus or Copenhagen, aged 50–64 years. and who were cancer-free, were randomly selected and invited. Attrition rate was > 20% after three years of follow-up time. Hypertension was ascertained by a questionnaire; b Since only one study was evaluated, this criterion was not applied; c The study assessed population, exposure, and outcome of interest; d We considered the results to be precise: the sample was sufficiently large, and the 95% CI was sufficiently narrow; e Since only one study was evaluated, we were not able to test for publication bias; f We found a non-significant effect size of less than 1.00 per 10 dB; g The overall judgement of the quality of evidence was graded as “moderate”(3). Since only one study was available, we downgraded the overall level of evidence to “low” (2).