title: Type 2 diabetes mellitus, insulin-use and risk of bladder cancer in a large cohort study.
abstract: Type 2 diabetes mellitus (T2DM) is associated with increased bladder cancer incidence in some, but not all, studies. Many studies had limited statistical power and few examined risk by insulin-use, duration of diabetes or cancer stage. We examined the association between T2DM and bladder cancer incidence in the Cancer Prevention Study II Nutrition Cohort, a large prospective study with information on insulin-use and duration of diabetes. Diabetes and insulin-use were ascertained from a questionnaire at study enrollment in 1992 or 1993 and updated in 1997 and every 2 years thereafter. During follow-up through 2007, 1,852 cases of incident bladder cancer were identified among 172,791 participants. Multivariable adjusted relative risks (RRs) and 95% confidence intervals (CIs) were estimated using extended Cox regression modeling. There were no associations of T2DM with the risk of bladder cancer overall (RR = 1.01, 95% CI: 0.87-1.17), noninvasive disease (RR = 0.93, 95% CI: 0.76-1.14) or invasive disease (RR = 1.13, 95% CI: 0.91-1.40). Compared to participants without T2DM, risk of invasive bladder cancer was higher among participants who had had T2DM for >15 years (RR = 1.63, 95% CI: 1.09-2.43) and among those using insulin (RR = 1.64, 95% CI: 1.18-2.27). These results do not support an association of T2DM with overall bladder cancer incidence, but do suggest positive associations of long-term T2DM and insulin-use or other factors correlated with severe diabetes, with invasive bladder cancer incidence.
authors.affiliation: Epidemiology Research Program, American Cancer Society, Atlanta, GA 30303-1002, USA. christina.newton@cancer.org
authors.forename: Christina C
authors.initials: CC
authors.lastname: Newton
authors.forename: Susan M
authors.initials: SM
authors.lastname: Gapstur
authors.forename: Peter T
authors.initials: PT
authors.lastname: Campbell
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Jacobs
mesh_terms: D000368:Aged; D048909:Diabetes Complications / Q000453:epidemiology / Q000209:etiology*; D003924:Diabetes Mellitus, Type 2 / Q000150:complications* / Q000188:drug therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology / Q000209:etiology*
chemical_list: D007004:Hypoglycemic Agents; D007328:Insulin