Major Finding: Statistically significant associations were observed for cancers of the colon, rectum, and liver in both men and women (hazard ratios, 1.15, 1.28, and 2.40, respectively); for the pancreas and urinary bladder in men (HR, 1.47 and 1.10, respectively); and for the stomach, anus, and corpus and uterus in women (HR, 1.74, 2.44, and 1.20, respectively).
Data Source: The large, prospective NIH-AARP Diet and Health Study.
Disclosures: Dr. Lai said he had no relevant financial disclosures. The study was sponsored by the National Cancer Institute.
ORLANDO – Diabetes appears to be associated with an increased risk of several types of cancer and with an increased risk of cancer-related mortality in both men and women, findings from a large prospective study have shown.
Incidence rates for both diseases are increasing worldwide, and although prior research has demonstrated a decreased risk for prostate cancer in men with diabetes – perhaps due to the lower testosterone levels associated with diabetes – the association between diabetes and other cancers has not been well studied, Gabriel Lai, Ph.D., said at the meeting.
To better characterize the association between the two diseases, Dr. Lai and his colleagues analyzed data from the nearly 300,000 men and 200,000 women aged 50-71 years who participated in a diet and health study by the National Institutes of Health and AARP. After 11 years of follow-up, about 13,000 of the men and nearly 6,500 of the women in the study had died of cancer.
A modest inverse association between diabetes and total incident cancer was observed in men (hazard ratio, 0.96), but this stemmed largely from prostate cancer, as expected based on the prior research on diabetes and prostate cancer. In the current study, prostate cancer accounted for 42% of all the cancers in men, and when it was excluded from the analysis, diabetes was found to be positively associated with cancer in men (HR, 1.08) and with cancer mortality in men (HR, 1.20), said Dr. Lai, a cancer prevention fellow at the National Cancer Institute.
Diabetes also was found to have a modest association with cancer in women (HR, 1.06) and with cancer mortality in women (HR, 1.15).
Statistically significant associations were observed for cancers of the colon, rectum, and liver in both men and women (HR, 1.15, 1.28, and 2.40, respectively); for the pancreas and urinary bladder in men (HR, 1.47 and 1.10, respectively); and for the stomach, anus, and corpus and uterus in women (HR, 1.74, 2.44, and 1.20, respectively). The risk estimates for cancers of the pancreas and urinary bladder in women with diabetes were similar to those in men, and the risk estimate for stomach cancer in men was similar to that in women, but these did not reach statistical significance, Dr. Lai said.
No association between diabetes and lung, skin, or other cancers was observed, he noted.
Diabetes in the NIH-AARP study was assessed by self-report in the predominantly white, non-Hispanic cohort, and all analyses included adjustment for age, education, body mass index, smoking status, self-reported health status, physical activity, vitamin supplement use, alcohol intake, diet (fruit, vegetable, and meat consumption), family history of cancer, and – among women – hormonal therapy.
The findings provide additional evidence that abnormal insulin and glucose signaling contribute to cancer risk, and suggest that in addition to myriad other benefits, avoiding diabetes through diet, exercise, and maintenance of healthy body weight potentially reduces the risk for cancer development and mortality, Dr. Lai said.
Further study is needed to elucidate the biologic mechanisms of the association between diabetes and cancer, he concluded.