Association between XRCC1 Arg280His and risk of head and neck cancer under four genetic models.

<p>Forest plots for a: His vs. Arg; b: HisHis vs. ArgArg; c: ArgHis vs. ArgArg; d: HisHis+ ArgHis vs. ArgArg. Fixed-effects models were used for a, b, c, and d. Squares and horizontal lines represent the study-specific OR and 95% CI respectively; diamond indicates the summary OR and 95% CI.