Items for critical appraisal | Were the two groups similar and recruited from the same population? | Were the exposures measured similarly to assign people to both exposed and unexposed groups? | Was the exposure measured in a valid and reliable way? | Were confounding factors identified? | Were strategies to deal with confounding factors stated? | Were the groups/participants free of the outcome at the start of the study (or at the moment of exposure)? | Were the outcomes measured in a valid and reliable way? | Was the follow up time reported and sufficient to be long enough for outcomes to occur? | Was follow up complete, and if not, were the reasons to loss to follow up described and explored? | Â | Â | Â | Were strategies to address incomplete follow up utilized? | Â | Â | Â | Â | Â | Â | Â | Overall appraisal | Quality of the evidence | ||||||||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
studies | yes | No | Unclear | Not applicable | yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Yes | No | Unclear | Not applicable | Â | Â |
Thomson et al. [53]. | √ |  |  |  | √ |  |  |  |  | √ |  |  | √ |  |  |  | √ |  |  |  |  |  |  | √ | √ |  |  |  |  |  | √ |  | √ |  |  |  | √ |  |  |  | √ |  |  |  | Included | High |