LAUSR

Background In our previous study, we have conducted a case-control study to demonstrate the mitochondrial DNA (mtDNA) haplogroups in the development of knee osteoarthritis (OA). However, there were no mtDNA haplogroups associated with the development of knee OA. Objectives The objective of this study was to elucidate the role of mtDNA haplogroups in the development of knee OA in prospective on-going community-based cohort. Methods This cohort was established in 2001 to investigate the epidemiologic characteristics of major chronic diseases in Korea by the Korean Genome and Epidemiology Study, Centre for Disease Control (KCDC). The epidemiologic data and knee radiographs were obtained from the second follow-up (2005–2006) and the sixth follow-up (2013–2014), and DNA was distributed from the fourth follow-up (2009–2010). The Kellgren-Lawrence (K/L) score was measured using a knee X-ray taken at each visit. The mtDNA was analysed by multiplex mutagenetically separated polymerase chain reaction to determine the mtDNA haplogroups (M, G, D, D4, D5, M7, M8, M9, M10, N, A, N9, R, F, B). The frequency of the mtDNA haplogroup was compared between the group with knee OA (K/L≥2 or underwent total knee replacement arthroplasty) and the group without knee OA (K/L<2) at the 6th follow-up in the cohort of K/L=0 at the second follow-up. Multiple logistic regression was used to determine relative risk (RR) of mtDNA haplogroups for OA by adjusting sex, age, and body mass index (BMI). Results A total of 1115 epidemiological data, knee radiographs, and DNA samples were distributed. Of these, 572 were cohorts with K/L=0 in the second follow-up, and 438 underwent knee X-ray examination at the sixth follow-up visit. Among them, 160 were classified as Knee OA by K/L grading and 278 were classified as control group. The mean age (59.4±8.5 and 64.3±6.8), the number of male patients (61 [21.9%] and 11 [6.9%]), and the mean BMI (24.0±3.1 and 25.0±3.0) were significantly different between normal and OA group (p<0.001). In comparison of frequency of mtDNA haplogroup between two groups, haplogroup B was significantly higher in OA group (unadjusted RR=1.794, p=0.030 and adjusted RR=2.346, p=0.005). Conclusions Our data suggested that mtDNA haplogroup B contributed to the development of knee OA in Korean. Further study is ongoing to confirm the relationship between the progression of knee OA and mtDNA haplogroups. Acknowledgements Our previous study was presented at 4th International Congress on Controversies in Rheumatology and Autoimmunity, Bologna, Italy, 9–11 March 2017. Disclosure of Interest None declared