Methods for conducting systematic reviews of risk factors in low- and middle-income countries.

There are many studies on child conduct problems and youth violence in LMICs which have not been included in prior reviews. Most research on these subjects in LMICs has been produced in the last two-three decades and mostly in middle-income countries, such as China, Brazil, Turkey, South Africa and Russia. Based on our findings, it appears that many studies of child conduct problems and youth violence in LMICs are reported in English, Chinese, Spanish and Portuguese, but few such studies are published in French, Arabic or Russian. If non-English language searches and screening had not been conducted in the current review, 15% of eligible studies would have been missed. Although there are benefits to non-English language searches and the inclusion of non-English studies in meta-analyses, systematic reviewers also need to consider the resources required to incorporate multi-lingual research.