Objective: Incidence rates for diabetes and cancer are increasing globally. Epidemiologic studies have observed increased risk between diabetes and several cancers, including breast, colorectal, liver, and pancreatic. Yet, the association between diabetes and other cancers remains unclear. Thus, we evaluated the association between diabetes and cancer incidence and mortality in the prospective NIH-AARP Diet and Health Study.

Methods: Our analysis included 295,287 men and 199,665 women who resided in one of eight states (CA, FL, GA, LA, MI, NC, NJ, and PA) at baseline (1995-1996). Diabetes was assessed by self-report. Hazard ratios and 95% confidence intervals were estimated from Cox proportional hazards models adjusted for age, education, BMI, smoking status, self-reported health status, physical activity, vitamin supplement use, intake of alcohol, fruits, vegetables and meat, family history of cancer, and among women, menopausal hormonal therapy.

Results: After 11 years of follow-up, 55,888 men and 26,364 women were diagnosed with incident cancer; 13,037 men and 6,474 women died of cancer. We observed a modest inverse association between diabetes and total incident cancer in men (HR=0.96, 95% CI: 0.93-0.99) and a modest positive association in women (1.06, 1.02-1.12). Inverse associations in men stemmed from prostate cancer (n=23,483 cases, 42% of incident cancers; 0.75, 0.71-0.79). After excluding prostate cancer, diabetes became positively associated with cancer in men (1.08, 1.05-1.12). For total cancer mortality, we observed a positive association in men (1.20, 1.14-1.27) and women (1.15, 1.05-1.26). Associations were similar for cancers occurring during the first year, years 1 to 5, and years 5 to 11 of follow-up.

When evaluated by site, diabetes was positively associated with cancers of the colon (1.15, 1.04-1.28; 1.33, 1.13-1.55), rectum (1.28, 1.08-1.51; 1.45, 1.10-1.91), and liver (2.40, 1.90-3.02; 1.90, 1.16-3.10) in both men and women. In men, diabetes was positively associated with cancers of the pancreas (1.47, 1.24-1.75) and urinary bladder (1.10, 1.01-1.20); risk estimates for these cancers were similar in women but not statistically significant. In women, diabetes was positively associated with cancers of the stomach (1.74, 1.14-2.67), anus (2.44, 1.18-5.02), and corpus and uterus (1.20, 1.01-1.41); the risk estimate for stomach cancer was similar in men but not statistically significant. We observed no association between diabetes and lung (1.02, 0.94-1.10; 0.97, 0.85-1.10), skin (0.99, 0.88-1.11; 0.97, 0.76-1.24), or other cancers.

Discussion: Diabetes was associated with lower rates of incident prostate cancer in men, but with higher incidence rates for a number of other cancers in both sexes. Diabetes was also associated with higher cancer mortality rates. Our results suggest that preventing or controlling diabetes may contribute to decreased cancer incidence and mortality.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 947. doi:10.1158/1538-7445.AM2011-947