Figure 2. Association between XRCC1 Arg194Trp and risk of head and neck cancer under four genetic models.

Forest plots for a: Trp vs. Arg; b: TrpTrp vs. ArgArg; c: ArgTrp vs. ArgArg; d: TrpTrp+ ArgTrp vs. ArgArg. Random-effects models were used for a, c, and d; a fixed-effects model was used for b. Squares and horizontal lines represent the study-specific OR and 95% CI respectively; diamond indicates the summary OR and 95% CI.