SPP1 and neoplasm: There was no significant difference between the two groups for any of the demographic parameters except for the gender (OR: 0.78, 95% CI 0.62–0.99; p = 0.04), and the tumor size, which was larger for the OPN group (weighted mean difference [WMD]:−0.74; 95% confidence interval [CI], −1.11 to −0.37; p<0.0001).