Table A49.
Summary of findings table for the association between road traffic noise exposure and the change in waist circumference.
| Question | Does Exposure to Road Traffic Noise Increase the Risk of Obesity | |||
|---|---|---|---|---|
| People | Adult population (men and women) | |||
| Setting | Residential setting: people living in Stockholm in areas located around the airport (Sweden), people living in Oslo (Norway), People living in Aarhus or Copenhagen (Denmark) | |||
| Outcome | Change in waist circumference (cm) | |||
| Summary of findings | Change in waist circumference per 10 dB increase in road traffic noise level (LDEN) | 0.17 (95% CI: −0.06–0.40) cm | ||
| Number of participants (# studies) | 71,431 (3) | |||
| Number of cases | NR | |||
| Rating | Adjustment to rating | |||
| Quality assessment | Starting rating | 3 cross-sectional studies # | 2 (low) | |
| Factors decreasing confidence | Risk of bias | Limited a | No downgrading | |
| Inconsistency | Serious b | Downgrading | ||
| Indirectness | None c | No downgrading | ||
| Imprecision | Serious 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 | 1 (very low) | |||
# Since only cross-sectional studies were available, we started with a grading of “low” (2); a The quality of the studies was judged as high; b Results across studies differed in the magnitude and direction of effect estimate (see Figure 8.1 of the complete review). This was confirmed by the results of the heterogeneity analysis, demonstrating “strong” heterogeneity (I2residual = 84.4%); c The study assessed population, exposure and outcome of interest; d We considered the results to be precise enough: The standard deviation of the reported effect size was smaller than the mean difference in waist circumference; e Since the number of available estimates was small, it was not possible to test for publication bias or small study bias; f Two studies found a harmful effect of road traffic noise. There was evidence of a non- significant exposure-response gradient: After aggregating the results of the three evaluated studies, we found a non-significant effect size of 0.17 per 10 dB. The noise range of the study under evaluation was ~40–65 dB. This means that if the road traffic noise level increases from 40 to 65 dB, the waist circumference increased with 0.43 cm (this is probably less than 3-5% change in waist circumference, which is considered clinically significant); g Residual confounding primarily due to the way exposure was assessed cannot be ruled out. For the rest we were not able to draw any conclusions whether possible residual confounders or biases would reduce our effect estimate.