Summary of Systematic Review.

Exposures investigated by lead author of study. An “X” indicates whether the agent was evaluated by a particular study. The last row indicates whether there was sufficient evidence to demonstrate the studies estimated heterogeneous effects. Drugs with an asterisk (*) next to their names identify those implicated by the meta-analysis. Plus signs (+) indicate exclusion from analysis due to incompatible definition of exposure and/or reference group. “Greater Than” symbols (>) and “Less Than” symbols () or protection (本研究第一作者所考察的暴露因素。标记为"X"的条目，表示该暴露因素是否被某项特定研究纳入评估。最后一行用于标注是否存在足够证据，证明各项研究估算得到了异质性效应。名称旁带有星号（*）的药物，为该荟萃分析（meta-analysis）所关联的药物。带有加号（+）的条目，则表示因暴露因素与/或参照组的定义不兼容，该暴露因素被排除出本次分析。"Greater Than"符号（>）与"Less Than"符号（）或保护（