Family history of diabetes mellitus and risk of colorectal cancer: A nationwide cohort study

Aims: Studies have shown the association between personal history of diabetes mellitus (DM type 1/2) and risk of colorectal cancer (CRC). This study aims to find the association between the family history of diabetes and CRC risk. Methods: This large nationwide cohort study leveraged data from several Swedish nationwide registers (follow-up: 1964–2018) to compare the risk using standardized incidence ratio (SIR). Results: 11,784,567 individuals (668,348 with DM) were included and followed for up to 54 years (median = 28 years). Those with a personal history of DM had a 1.4-fold increased risk of CRC compared to those without DM (95 % CI: 1.39–1.45). However, the addition of a family history of DM in 1 FDR or ≥ 2 FDRs did not significantly alter the increased risk of early-onset or late-onset CRC. Conclusion: Leveraging one of the world's largest family-disease datasets, our cohort study confirmed that personal history of diabetes is associated with an increased risk of colorectal cancer, but we did not find an association between a family history of diabetes and risk of colorectal cancer.