Table 5.
Summary of findings.
| Effect of occupational exposure to noise on cardiovascular disease among workers | |||||
|---|---|---|---|---|---|
|
Population: all ≥ 15 years workers Settings: all countries and work settings Exposure: occupational exposure to noise (defined as ≥85 dBA) Comparator: no occupational exposure to noise (defined as <85 dBA) | |||||
| Outcomes | Relative effect (95% CI) | No. of participant (studies) | Navigation Guide quality of evidence rating | Navigation Guide strength of evidence rating for human evidence | Comments |
| IHD prevalence | Inadequate evidence for harmfulness | No eligible studies found. | |||
| IHD incidence | –x | 11,758 (2 studies) | ⊕⊝⊝ Lowa,b |
Limited evidence of harmfulness | Better indicated by lower values. The available evidence is sufficient to determine the effects of the exposure, but confidence in the estimate is constrained. As more information becomes available, the observed effect could change, and this change may be large enough to alter the conclusion. A positive relationship is observed between exposure and outcome where chance, bias, and confounding cannot be ruled out with reasonable confidence. |
| IHD mortality | –x | 198,926 (4 studies) | ⊕⊝⊝ Lowa,c |
Inadequate evidence of harmfulness | Better indicated by lower values. Studies permit no conclusion about a toxic effect. The available evidence is insufficient to assess effects of the exposure. More information may allow an estimation of effects. |
| Stroke prevalence | Inadequate evidence for harmfulness | No eligible studies found. | |||
| Stroke incidence | –x | 170,000 (2 studies) | ⊕⊝⊝ Lowa,d |
Inadequate evidence of harmfulness | Better indicated by lower values. Studies permit no conclusion about a toxic effect. The available evidence is insufficient to assess effects of the exposure. More information may allow an estimation of effects. |
| Stroke mortality | –x | 195,539 (3 studies) | ⊕⊝⊝ Lowa,d |
Inadequate evidence of harmfulness | Better indicated by lower values. Studies permit no conclusion about a toxic effect. The available evidence is insufficient to assess effects of the exposure. More information may allow an estimation of effects. |
| Hypertension prevalence | Inadequate evidence for harmfulness | No eligible studies found. | |||
| Hypertension incidence | –x | 147,820 (3 studies/4 estimates) | ⊕⊝⊝ Lowa,d,c,e |
Inadequate evidence of harmfulness | Better indicated by lower values. Studies permit no conclusion about a toxic effect. The available evidence is insufficient to assess effects of the exposure. More information may allow an estimation of effects. |
| Hypertension mortality | Inadequate evidence for harmfulness | No eligible studies found. | |||
CI: confidence interval; RR: relative risk.
Navigation Guide quality of evidence ratings:
High quality: Further research is very unlikely to change our confidence in the estimate of effect.
Moderate quality: Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate.
Low quality: Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate.
Navigation Guide strength of evidence ratings:
Sufficient evidence of toxicity/harmfulness: The available evidence usually includes consistent results from well‐designed, well‐conducted studies, and the conclusion is unlikely to be strongly affected by the results of future studies. For human evidence a positive relationship is observed between exposure and outcome where chance, bias, and confounding, can be ruled out with reasonable confidence.
Limited evidence of toxicity/harmfulness: The available evidence is sufficient to determine the effects of the exposure, but confidence in the estimate is constrained by such factors as: the number, size, or quality of individual studies, the confidence in the effect, or inconsistency of findings across individual studies. As more information becomes available, the observed effect could change, and this change may be large enough to alter the conclusion. For human evidence a positive relationship is observed between exposure and outcome where chance, bias, and confounding cannot be ruled out with reasonable confidence.
Inadequate evidence of toxicity/harmfulness: Studies permit no conclusion about a toxic effect. The available evidence is insufficient to assess effects of the exposure. Evidence is insufficient because of: the limited number or size of studies, low quality of individual studies, or inconsistency of findings across individual studies. More information may allow an estimation of effects.
Evidence of lack of toxicity/harmfulness: The available evidence includes consistent results from well‐designed, well‐conducted studies, and the conclusion is unlikely to be strongly affected by the results of future studies. For human evidence more than one study showed no effect on the outcome of interest at the full range of exposure levels that humans are known to encounter, where bias and confounding can be ruled out with reasonable confidence. The conclusion is limited to the age at exposure and/or other conditions and levels of exposure studied.
Because we are very uncertain about the effect estimate, we do not present it in this summary of findings table.
Downgraded by two level (−2) for very serious concerns for indirectness.
Upgraded by one level (+1) for large effect size (defined as RR ≥ 1.25).
Downgrade by one level (−1) for serious concerns for publication bias.
Downgrade by one level (−1) for serious concerns for imprecision.
Upgrade by one level (+1) for residual confounding.