Myotonic dystrophy type 1 in South Korea: a comprehensive analysis of cancer and comorbidity risks

Background and purpose Myotonic dystrophy type 1 (DM1) is an inherited neuromuscular disorder characterized by myotonia and progressive muscle weakness. Beyond the primary symptoms, there is growing concern regarding a higher incidence of certain comorbidities in DM1 patients, including cancer, diabetes, thyroid dysfunction, and cataracts. This study was designed to examine the occurrence of these conditions among patients diagnosed with DM1 in South Korea, using data from the National Health Insurance Service database. Methods The study undertook a comprehensive review of 3,842 patients diagnosed with DM1 between 2012 and 2018. We assessed the incidence of cancer and the prevalence of diabetes, thyroid dysfunction, and cataracts among these patients, comparing their rates to those in the general population. Results In the study cohort, 463 out of 3,842 DM1 patients (12.04%) were diagnosed with cancer, indicating a substantial elevation in cancer risk with an overall standard incidence ratio of 1.9 (95% CI = 1.6–2.3, p