Table 3.
Diabetes mellitus and the incidence of bladder cancer.
| Study Author | Study Year | Total No. of Patients |
Total No. of Studies | Study Type | Comments |
|---|---|---|---|---|---|
| Xu et al. [31] | 2017 | 13,505,643 | 21 (includes studies A–F, H, and I) | Meta-analysis of cohort studies | In sub-group analyses, positive associations have exclusively been seen in men. |
| Zhu et al. [32] | 2013 | 14,885,014+ | 29 (includes studies A–F and H) | Meta-analysis of cohort studies | “In stratified analysis, the RRs of bladder cancer were 1.36 (1.05–1.77) for diabetic men and 1.28 (0.75–2.19) for diabetic women, respectively”. |
| Zhu et al. [33] | 2013 | 13,670,340+ | 36 (includes studies A–F and H) | Updated meta-analysis of observational studies | “In analysis stratified by study design, diabetes was positively associated with risk of bladder cancer in case–control studies (RR = 1.45, 95% CI 1.13–1.86, p = 0.005, I2 = 63.8%) and cohort studies (RR = 1.35, 95% CI 1.12–1.62, p < 0.001, I2 = 94.3%), but not in cohort studies of diabetic patients (RR = 1.25, 95% CI 0.86–1.81, p < 0.001, I2 = 97.4%). The RRs of bladder cancer were 1.38 (1.08–1.78) for men and 1.38 (0.90–2.10) for women with diabetes, respectively”. |
| Larsson et al. [34] | 2006 | 1,558,356 | 16 (includes studies B and G) | Meta-analysis | “Stratification by study design found that diabetes was associated with an increased risk of bladder cancer in case–control studies (RR = 1.37, 95% CI 1.04–1.80, p = 0.005) and cohort studies (RR = 1.43, 95% CI 1.18–1.74, p = 0.17), but not in cohort studies of diabetic patients (RR = 1.01, 95% CI 0.91–1.12, p = 0.35)”. |
| Xu et al. [35] | 2013 | 8,009,591 | 15 (includes studies B–F) | Meta-analysis of cohort studies | “When restricting the analysis to studies that had adjusted for cigarette smoking (n = 6) or more than three confounders (n = 7), the RRs were 1.32 (95% CI 1.18–1.49) and 1.20 (95% CI 1.02–1.42), respectively”. |
| Fang et al. [36] | 2013 | 9,752,495 | 24 (includes studies A and B–F) | Meta-analysis of observational studies | “Cohort studies showed a lower risk (RR 1.23, 95% CI 1.09–1.37) than case–control studies (odds ratio 1.46, 95% CI 1.20–1.78). The positive association was significant only in women (RR 1.23, 95% CI 1.02–1.49), but not in men (RR 1.07, 95% CI 0.97–1.18)”. |
| Yang et al. [37] | 2013 | 5,463,339 | 23 (includes studies A, B, and G) | Meta-analysis | “Analysis of subgroups demonstrated this to be the case in both case–control studies (OR = 1.59, 95% CI 1.28–1.97, I2 = 58%) and cohort studies (RR = 1.70, 95% CI 1.23–2.33, I2 = 96%). There was no gender difference in DM-associated bladder cancer risk. Bladder cancer risk was increased in Asia and the North America region, but not in Europe”. |
A = Tseng et al., 2009, B = Tripathi et al., 2002, C = Larsson et al., 2008, D = Khan et al., 2006, E = Ogunleye et al., 2009, F = Atchison et al., 2011, G = Adami et al., 1991, and H = Marrianne et al., 2009.