Odds ratios (ORs) for associations between two single nucleotide polymorphisms (Arg194Trp and Arg399Gln) in the x-ray repair cross-complementing group 1 gene ( XRCC1 ) and bladder cancer risk. The size of the black square corresponding to each study is proportional to the sample size and the center of each square represents the OR. The horizontal line shows the corresponding 95% CI of the OR. Pooled OR is represented by a hollow diamond. A) Arg194Trp TT genotypes versus the CC-plus-CT genotype; B) Arg399Gln GA genotypes versus the GG-plus-AA genotype. CI, confidence interval.