1.4 Quality assessment
We used the Newcastle-Ottawa Scale (NOS) to assess the quality of each cohort and case-control studies 44. It evaluated the quality of articles from case and control selection, exposure record, the comparability and the outcome. The average score of quality assessment was 8.1 of the cohort studies and 8.0 of the case-control studies. The lowest was 7 and the highest was 9. (Table S3- S4)