Cancer Risk in Elderly Korean Patients with Neurodegenerative Disease and its relation to Type 2 Diabetes

Abstract

Introduction: Some studies suggest that neurodegenerative diseases (NDs), cancer, and type 2 diabetes (T2D) are all related to protein misfolding and may be linked. This study aimed to determine whether these diseases are associated with each other. Objective: The aim of the study was to investigate the difference in cancer incidence according to the presence or absence of T2D in the ND group and the control group during the 10-year follow-up period. Methods: A population-based 10-year follow-up study was conducted using the Korean National Health Insurance Service Database between 2002 and 2015. The study population included the ND group (n = 9,292) and the control group (n = 46,742), who were aged 60 to 84 years. Cox proportional hazards regression was used to estimate multivariable-adjusted hazard ratios (HRs) for cancer. Results: ND and/or T2D were newly diagnosed in both groups during the follow-up period. The newly diagnosed ND cases before cancer onset were 2,412 (26.0%) and 15,435 (33.0%) in the ND and control groups, respectively (p < 0.01). The newly diagnosed T2D cases were 4,691 (50.5%) and 25,695 (55.0%) in the ND and control groups, respectively (p < 0.01). At the end of the observation period, the number of cancer patients was 2,040 (22.0%) and 8,628 (18.5%) in the ND and control groups, respectively (p < 0.01). The ND group was associated with an increased risk of cancer (HR = 1.25). In both groups, newly diagnosed ND and T2D showed an additive effect on cancer incidence during the follow-up period. Conclusion: This study showed that cancer incidence was positively associated with ND and T2D. These results show that ND, cancer, and T2D are related. More replication studies are needed to address the association between ND, cancer, and T2D.