Chondroitin Sulfate for Osteoarthritis – Is There a Risk for Cancer: an Analysis of Osteoarthritis Initiative Data

Abstract

The aim of this study was to evaluate the association between chondroitin   sulfate (CS) use and incidence of self-reported cancer during 6-year follow up in the     publicly available Osteoarthritis Initiative (OAI) cohort participants. Materials and Methods: The current study included analysis of 6-year longitudinal data obtained from the OAI progression (n= 1390) and incidence (n = 3284) subcohorts that are publicly available at https://nda.nih.gov/oai/. The inclusion criteria for OAI were the following: age between 45 and 79 years for both subcohorts, symptomatic tibiofemoral knee osteoarthritis (OA) for the progression subcohort, and the presence of established or putative risk factors for incident knee OA for the incidence subcohort. The OAI participants were recruited and enrolled between February 2004 and May 2006 at four recruitment centres in the United States. This study received ethical approval from each recruitment centre. All participants provided written informed consent. To reduce the risk of bias, only participants who did not take CS at baseline were included in the analysis (a “new-user” design). Results: 570 (18%) new users of CS and 2597 (82%) CS non-users were compared. In the CS user group, 294 (51.6%) participants received CS for more than one year, 291 (33.5%) for more than 2 years, 123 (21.6%) for more than 3 years, and 60 (10.5%) for more than 4 years. None of the participants received CS for more than 5 years. CS users and non-users were of the same age, had similar male/female ratio, and similar body mass index. In the non-user group, there were more African-American participants and there were more current smokers. 160 (6.2%) and 37 (6.5%) cases of incident self-reported cancer in the non-users and user groups were identified. There was no association between the use of CS and incident self-reported cancer in the non-adjusted analyses. The adjustments for age, race and smoking status did not change the results. Conclusion: The results of the current study did not show an association between CS use and self-reported cancers. Considering the complex function of CS in the development and progression of malignant tumors, there is a need for further epidemiological studies evaluating CS effects on specific types of cancers and in different genetic backgrounds.