Risks and Familial Coaggregation of Autism Spectrum Disorder Among First-Degree Relatives of Individuals With Colorectal Cancer

Objective Associations between major mental disorders (MMDs) and colorectal cancer (CRC) have been reported; however, it remains unknown whether this association extends to an individual’s kinship. The aim of this study was to explore the risks of MMDs in first-degree relatives (FDRs) of individuals with CRC.Methods We used data from the Taiwan National Health Insurance Research Database. FDRs of individuals with CRC were identified as the index group, and a demographic-matched group was also included as the controls. The primary outcome was the risk of an MMD. A Poisson regression model with robust error variance was used to estimate the relative risks and 95% confidence intervals.Results A total of 68,965 FDRs of individuals with CRC (38,024 males and 30,941 females) and 275,860 matched controls were included. After adjustments for potential confounders, the FDR-CRC group had a higher risk of autism spectrum disorder than the controls, especially in the males of fathers with CRC. In addition, individuals who had a son with CRC had a higher risk of bipolar disorder than the controls, especially females. Males whose mother had CRC had higher risks of attention deficit hyperactivity disorder and general anxiety disorder than the controls.Conclusion With the unique association identified in this study between FDRs of individuals with CRC and the risk of MMDs, genetic studies are encouraged to explore the complicated etiologies behind this association.