Quality appraisal

The risk of bias and the methodology quality of the identified publications were assessed using the Newcastle-Ottawa Scale (NOS) for cohort studies and a NOS adapted version for cross-sectional studies [9]. NOS is a star-rating based system, with a maximum of 9 scores for cohort studies, randomized controlled trials and a maximum of 10 scores for cross-sectional studies. Each study’s quality is assessed using the following grading algorithms: with a NOS score of 7 and above, it is considered a high-quality study, studies with 4 to 6 points are considered medium-quality, while those with 0 to 3 scores are considered low-quality [10].