*3.6. Case-Control Studies*

The studies with a case-control design numbered 11/46 (23.9%) in the selection, with a total of 611 cases vs. 227 controls [14,19,20,32,37,42,47,49,50,53,54]. The overall prevalence was 27.3% (167/611) and 4.4% (10/227) in cases and controls, respectively. The pooled odds ratio (OR) was 7.8406 (95% CI, 4.3425–14.1567; *p*-value < 0.00001; I2: 34.7%) for the association between HPV infection and occurrence of BCa (Table 5; Figure 3).

**Table 5.** HPV prevalence stratified by the presence (case) or absence (control) of any type of bladder tumor (case-control studies).

