Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, 1300 S. Second Street, Suite 300, Minneapolis, MN 55454-1015, USA.
Cancer Causes Control. 2013 Mar;24(3):603-8. doi: 10.1007/s10552-012-0143-3. Epub 2013 Jan 8.
Studies have indicated that diabetes is a risk factor for bladder cancer; however, many failed to adjust for confounding variables. An earlier publication from the Iowa Women's Health Study reported a positive association of baseline diabetes with bladder cancer risk between 1986 and 1998, although the number of cases was small (n = 112). We re-examined the diabetes-bladder cancer risk association by accounting for 12 more years of follow-up and assessed whether the association varied by diabetes duration, body mass index, or waist-to-hip ratio (WHR).
Proportional hazards regression was used to estimate the hazard ratio (HR) of bladder cancer (n = 277) in relation to diabetes (before enrollment and during follow-up) and diabetes duration using a time-dependent approach.
In a multivariate time-dependent analysis, the HR for bladder cancer was 1.69 (95 % CI 1.40-2.41) in relation to diabetes among 37,327 postmenopausal women initially free of cancer. There was an interaction between diabetes and WHR (p = 0.01). Bladder cancer HR in diabetic women with WHR > 0.9 was 2.5 times higher than expected. There was no dose-response relation of bladder cancer risk with diabetes duration. Compared to no diabetes, HRs were 1.77, 2.03, and 1.55 for diabetes durations of ≤5, 6-10, and >10 years, respectively.
We confirmed a positive association between diabetes and bladder cancer risk among white postmenopausal women. We also observed a synergistic interaction between diabetes and high WHR in bladder cancer development that might be explained by increased insulin resistance and inflammation related to abdominal obesity.
有研究表明糖尿病是膀胱癌的一个风险因素，但许多研究未能调整混杂变量。爱荷华妇女健康研究的早期研究报告称，在 1986 年至 1998 年间，基线糖尿病与膀胱癌风险之间存在正相关，尽管病例数量较少（n=112）。我们通过纳入 12 年的随访时间，重新检查了糖尿病与膀胱癌风险之间的关联，并评估了这种关联是否因糖尿病持续时间、体重指数或腰围-臀围比（WHR）而异。
使用比例风险回归估计了膀胱癌（n=277）与糖尿病（在登记前和随访期间）和糖尿病持续时间之间的风险比（HR），采用时间依赖性方法。
在多变量时间依赖性分析中，37327 名绝经后最初无癌症的女性中，与糖尿病相关的膀胱癌 HR 为 1.69（95%CI 1.40-2.41）。糖尿病与 WHR 之间存在交互作用（p=0.01）。WHR>0.9 的糖尿病女性膀胱癌 HR 是预期的 2.5 倍。糖尿病持续时间与膀胱癌风险之间没有剂量反应关系。与无糖尿病相比，糖尿病持续时间分别为≤5、6-10 和>10 年的 HR 分别为 1.77、2.03 和 1.55。
我们证实了白种绝经后妇女中糖尿病与膀胱癌风险之间存在正相关。我们还观察到糖尿病与高 WHR 之间在膀胱癌发展方面存在协同交互作用，这可能与与腹部肥胖相关的胰岛素抵抗和炎症增加有关。
