Cancer ups risk of incident diabetes
Cancer appears to independently increase the risk of diabetes, regardless of traditional risk factors, according to a recent Korea study.
“The increased risk of diabetes was evident shortly after cancer development, was strongest in the first 2 years after cancer diagnosis and remained elevated throughout the rest of follow-up,” said researchers.
Over 3,492,935.6 person-years of follow-up in 494,189 adults (mean age 41.8±12.5 years; 50 percent female), 15,130 individuals developed cancer. [JAMA Oncol 2018;doi:10.1001/jamaoncol.2018.1684]
Cases of incident diabetes were reported in 26,610 individuals, 834 of which occurred after incident cancer diagnosis, yielding an incidence rate of 17.4 per 1,000 person-years. The corresponding incidence rate of diabetes in participants without cancer was 7.5 per 1,000 person-years.
An age- and sex-adjusted proportional hazards regression model showed that there was a significant association between incident diabetes and the development of cancer (hazard ratio [HR], 1.36; 95 percent CI, 1.27–1.46). This relationship remained significant even after adjusting for precancer diabetes risk factors and comorbidities (HR, 1.35; 1.26–1.45; p<0.001 for both).
Analysis by time since cancer development showed that the risk of diabetes was highest in the first 2 years after cancer diagnosis (HR, 1.47; 1.35–1.60) but remained significant even after 6–10 years after (HR, 1.19; 1.00-1.43; p<0.001 for both).
Type of cancer also had an effect on incident diabetes risk. Pancreatic (HR, 5.15; 3.32–7.99), kidney (HR, 2.06; 1.34–3.16) and liver (HR, 1.95; 1.50–2.54) cancers yielded the highest risk, while ovarian (HR, 1.07; 0.48–2.38) and prostate (HR, 0.81; 0.55–1.20) cancers were not associated with the likelihood of diabetes development.
“The increased risk of diabetes after cancer may be related to cancer-management interventions,” explained researchers, further noting that corticosteroids, widely used in different cancer treatments, have been shown to induce hyperglycaemia and diabetes development, potentially through reducing insulin sensitivity. [Endocr Pract 2009;15:469-474]
Chemotherapeutic agents like tamoxifen and L-asparaginase have likewise been shown to increase the risk of diabetes, researchers continued. “In our study, the increased risk of diabetes seemed to be highest in the period immediately after cancer development, further suggesting a role for toxicity of cancer treatments in diabetes development.”
For the study, researchers accessed the National Health Insurance Service-National Sample Cohort to collect information on participant baseline characteristics, comorbidities, cancer diagnoses and diabetes development. Using incident cancer as an exposure, researchers evaluated incident type 2 diabetes as the main study outcome.
“Physicians should remember that patients with cancer develop other clinical problems, such as diabetes, with higher frequency than individuals without cancer, and should consider routine diabetes screening in these patients,” said researchers.