Fig 1.
PRISMA flowchart for the selection of eligible studies.
Table 1.
Outcome measures sharing the same number in superscript belong to the same thematic category.
Table 2.
Synthesis of the impact of identified risk and protective factors on the development of mental health problems based on vote counting of the direction of effect.
The unknown directions of effect represent the factors which did not significantly contribute to the multivariate regression analyses and of which the direction of effect was not reported.
Fig 2.
Risk of bias graph showing each item presented as percentages across all observational studies with green: Low risk of bias, yellow: Unclear risk of bias, red: High risk of bias and grey: Not applicable.