Differential relationship between colorectal cancer and diabetes in a nationally representative sample of adults.

Background: Diabetes has been identified as a risk factor for developing colorectal cancer (CRC); however, the literature identifying groups most at risk is sparse. This study aims to understand the relationship between CRC and diabetes by age and race/ethnicity.

Methods: This is a cross-sectional study of data from the 2001-2014 National Health and Nutrition Examination Survey (unweighted n = 37,173; weighted n = 214,363,348). Individuals were categorized as having CRC if diagnosed with colon or rectal cancer and as having diabetes if told by a doctor they had diabetes, were taking insulin, or had an HbA1c ≥ 6.5%. Covariates included gender, age, race, marital status, educational level and income as a ratio of the poverty line. Multivariable logistic regression was used to assess the relationship between CRC and diabetes overall and stratified by age and by race.

Results: 24.32% of the sample with CRC also had diabetes. After adjusting for covariates, individuals with diabetes had a 47% greater probability of having CRC (p = 0.03). While significance did not persist after stratification for those ≥65 years (OR = 1.06, p = 0.74), those <65 years with diabetes had nearly 5-times higher odds of having CRC (OR = 4.78, p < 0.001). When stratified by race, both groups had statistically higher odds of having CRC; however, the odds for non-whites (OR = 1.87, p = 0.04) were higher compared to whites (OR = 1.54, p = 0.03).

Conclusion: Individuals younger than 65 and racial/ethnic minorities have higher odds of CRC when also diagnosed with diabetes. Targeted interventions for these populations, especially regarding screening recommendations, may result in earlier detection of CRC and improved health outcomes.