The significant interaction between age and diabetes mellitus for colorectal cancer: Evidence from NHANES data 1999-2016.

Background: Diabetes mellitus has been associated with elevated risk of colorectal cancer (CRC), although interaction between age and DM is unclear. We examined the relationship among DM, CRC and age.

Methods: 22,580 subjects aged ≥18 years were identified from the National Health and Nutrition Examination Survey (NHANES) database collected between 1999-2016. To account for the complex, stratified, multistage probability sampling design in NHANES, SASv9.4 Procedure Survey Methodology was applied. Univariate analysis compared individual baseline characteristics between subjects with and without DM. Multivariate logistic regression model assessed association between DM and CRC, in which the model included factors with p<0.05 in univariate analysis as covariates.

Results: Univariate analysis showed significant differences in age (p<0.0001), race (p<0.0001), smoking (p=0.0023) and body mass index (p<0.0001) between No-DM and DM. Multivariate analysis revealed significant interaction between age and DM (p=0.0004). Subjects with DM aged 18-65 were more likely to experience CRC (OR=4.47, 95%CI=(1.33-15.07); p=0.0157) compared to those without DM. Subjects with DM aged >65 were not at increased risk for CRC (OR=0.83, 95%CI=(0.43-1.59); p=0.5665) compared to those without DM.

Conclusions: Age, DM, and interaction between age and DM are risk factors for CRC. Individuals with DM aged 18-65 years have a higher CRC risk.