Table 2.
Quality assessment
| Study [ref.] | Methodological items | |||||
|---|---|---|---|---|---|---|
| Cohort or case−control study | Relevant age group | Independent assessment of exposure/outcome | Exposure- response or duration | COPD diagnosed by a physician, spirometry or cause of death | Relevant potential confounders considered | |
| Albin et al. [15] | + | − | + | + | − | + |
| Clausen et al. [16] | + | + | + | − | − | + |
| Dement et al. [25] | − | + | + | − | + | + |
| Dement et al. [22] | + | + | + | + | + | + |
| Ringen et al. [18] | + | + | + | + | + | + |
| Robinson et al. [19] | + | + | + | − | + | −c |
| Torén and Järvholm [20] | + | + | + | − | + | + |
| De Matteis et al. [24] | − | + | + | − | + | + |
| Hnizdo et al. [7] | − | + | + | −a | + | + |
| Molgaard et al. [17] | + | + | + | − | +b | −c |
| Tüchsen et al. [21] | + | + | + | − | +b | −c |
| Mastrangelo et al. [23] | + | + | + | + | + | + |
Items are scored as positive (+) or negative (−) according to checklist in Table 1. A positive score denotes less risk of bias.
aIn the study by Hnizdo et al. [7], analyses were made for trend with duration of employment, but the results are not shown separately among construction workers.
bThe studies by Molgaard et al. [17] and by Tüchsen et al. [21] included asthma in the diagnosis of COPD.
cThe studies did not adjust for smoking.