Fig. 2

Quality assessment of included articles Illustrates the Newcastle-Ottawa Scale evaluation of the methodological quality of included studies. Selection: Q1- Was the case definition adequate? Q2- Were the cases representative? Q3- Were the controls selected? Q4- Were the controls clearly defined? Comparability: Q5- Was the adjustment made for the most important risk factors? Q6-Was the adjustment made for other risk factors? Outcome: Q7- Was the outcome assessment adequate? Q8- Was the follow-up length sufficient? Q9- Was the follow-up process adequate? Each plot represents the publication bias assessment for the corresponding outcome. The symmetrical distribution around the pooled effect size suggests no significant bias, as confirmed by Egger’s tests (p-values > 0.05)