In 2000 there were 1.1 million lung or bronchial cancer deaths worldwide, with relatively limited evidence of causation other than for smoking. We aimed to search and appraise the literature regarding evidence for a causal relationship between air pollution and lung cancer according to the 10 Bradford Hill criteria for causality.
A MEDLINE search was performed using the following key words: 'lung neoplasm', 'epidemiology', 'human', 'air pollution'and 'not molec*'. The criteria for inclusion was: cited original research that described the study population, measured environmental factors, was of case control or cohort design, and was undertaken after 1982.
Fourteen papers (10 case control, four cohort studies) fulfilled the search criteria, with a sample size ranging from 101 cases and 89 controls, to a cohort of 552 cases and 138 controls. Of the 14 papers that fulfilled the search criteria the number of papers addressing each of the Bradford Hill criteria were as follows: Strength of association: eight studies demonstrated significant positive associations between environmental exposure and lung cancer with a relative risk range of 1.14-5.2. One study found a negative association with relative risk 0.28. Consistency: eight of 14 studies found significant positive associations and one of 14 a significant negative association. Specificity: tobacco smoking and occupational exposure were addressed in all studies (often crudely with misclassification). Temporality: exposure prior to diagnosis was demonstrated in nine studies. Dose-response relationship: evident in three studies. Coherence, analogy: not addressed in any study.
Evidence for causality is modest, with intermediate consistency of findings, limited dose-response evidence and crude adjustment for important potential confounders. Large studies with comprehensive risk factor quantification are required to clarify the potentially small effect of air pollution given the relatively large effects of tobacco smoking and occupational carcinogen exposure.
Pharmacology, Toxicology and Pharmaceutical Science
4
6%
Agricultural and Biological Sciences
3
5%
Biochemistry, Genetics and Molecular Biology
2
3%
Other
4
6%
Unknown
34
52%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 5. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 26 November 2022.
All research outputs
#7,785,559
of 28,701,752 outputs
Outputs from Respirology
#1,041
of 3,348 outputs
Outputs of similar age
#22,199
of 65,996 outputs
Outputs of similar age from Respirology
#8
of 17 outputs
Altmetric has tracked 28,701,752 research outputs across all sources so far. This one has received more attention than most of these and is in the 72nd percentile.
So far Altmetric has tracked 3,348 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 8.3. This one has gotten more attention than average, scoring higher than 68% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 65,996 tracked outputs that were published within six weeks on either side of this one in any source. This one has gotten more attention than average, scoring higher than 65% of its contemporaries.
We're also able to compare this research output to 17 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 52% of its contemporaries.
