Table 4.

Study-level results for risk of bias assessment.

	Agnoli et al. [43]	Bosco [62]	Inoue et al. [63]	Kabat et al. [48]	Osaki et al. [13]	Ronco et al. [51]	Rosato et al. [14]	Russo et al. [64]
Methods
Study design	Low	Low	Low	Low	Low	High	High	Low
Variables (confounders)	Low	High	High	Low	High	Low	Low	Unclear
Participants (eligibility, selection)	Low	Low	Low	Low	Low	Low	Low	Low
Data sources/predictor measurement	Low	High	Low	Low	Low	High	High	High
Data sources/outcome measurement	Low	Low	High	Low	Low	Low	Low	Low
Study size (adequate power)	Low	Low	Low	Low	Low	Low	Low	Low
Missing data analysis	High	High	High	Low	High	Low	Unclear	Unclear
Results
Participants (non-participation)	High	High	High	High	Low	Low	High	High