Appendix 2 Methodological quality of studies included

Joanna Briggs Institute Checklist	McKeigue et al.421	Taher et al.117	Poblador-Plou et al.216	McQueenie et al. 202018	Gavin et al 202019	De Smet et al.322	Sun et al. 202020
Case Control Studies£
1.Were the groups comparable other than the presence of disease in cases or the absence of disease in controls?	Yes
2.Were cases and controls matched appropriately?	Yes
3.Were the same criteria used for identification of cases and controls?	No
4.Was exposure measured in a standard, valid and reliable way?	Yes
5.Was exposure measured in the same way for cases and controls?	Yes
6.Were confounding factors identified?	Unclear
7.Were strategies to deal with confounding factors stated?	Yes
8.Were outcomes assessed in a standard, valid, and reliable way for cases and controls?	Yes
9.Was the exposure period of interest long enough to be meaningful?	Yes
10.Was appropriate statistical analysis used?	Yes
Total Score	8
Cohort Studies#
1.Were the 2 groups similar and recruited from the same population?		Yes	Yes	Yes
2.Were the exposures measured similarly to assign people		Yes	Yes	Yes
3.to both exposed and unexposed groups?		No	No	Yes
4.Was the exposure measured in a valid and reliable way?		Yes	Yes	Yes
5.Were confounding factors identified?		No	No	Yes
6.Were strategies to deal with confounding factors stated?		No	No	Yes
7.Were the groups/participants free of the outcome at the start of the study (or at the moment of exposure)?		No	No	No
8.Were the outcomes measured in a valid and reliable way?		Yes	Yes	Yes
9.Was the follow-up time reported and sufficient to be long enough for outcomes to occur?		No	Yes	Yes
10.Was follow-up complete, and if not, were the reasons for loss to follow-up described and explored?		Yes	Yes	Yes
11.Were strategies to address incomplete follow-up utilized?		No	Yes	Yes
12.Was appropriate statistical analysis used?		Yes	Yes	Yes
Total Score		6	8	11
Prevalence Dataπ
1.Was the sample frame appropriate to address the target population?					Yes	Yes	Yes
2.Were study participants sampled in an appropriate way?					Yes	Yes	Yes
3.Was the sample size adequate?					Yes	Yes	Yes
4.Were the study subjects and the setting described in detail?					Yes	No	Yes
5.Was the data analysis conducted with sufficient coverage of the identified sample?					Yes	Yes	Yes
6.Were valid methods used for the identification of the condition?					Yes	Yes	Yes
7.Was the condition measured in a standard, reliable way for all participants?					Yes	Yes	Yes
8.Was there appropriate statistical analysis?					Yes	Yes	Yes
9.Was the response rate adequate, and if not, was the low response rate managed appropriately?					Yes	Yes	Yes
Total Score					9	8	9

^£Maximum Attainable Score for Case Control Studies is 10.

^#Maximum Attainable Score for cohort Studies is 12.

^πMaximum Attainable Score for prevalence Studies is 9.