BackgroundSeveral studies have suggested farming occupation with exposure to pesticides as risk factor for rheumatoid arthritis (RA).ObjectivesWe investigated the association between pesticides exposure and risk of RA subsets in the Malaysian population.MethodsData from the Malaysian Epidemiological Investigation of Rheumatoid Arthritis (MyEIRA) population-based case-control study involving 1055 early RA cases and 1057 age, sex and residential area matched controls were analysed. All study subjects answered a structured questionnaire on a broad range of issues including occupational exposures to pesticides. The self-reported information on ever/never occupationally exposed to pesticides was used to estimate the risk of developing ACPA-positive and ACPA-negative RA. Association between pesticides exposure and the HLA-DRB1 shared epitope (SE) was evaluated.ResultsThe proportion of ACPA positivity in the RA patients was 64.4% and 1.9% in the normal controls. The presence of HLA-DRB1 SE alleles in RA patients was 40.2% and 15.8% in the normal controls. Our data demonstrated that occupational exposure to pesticides was significantly associated with an increased risk of developing RA in the Malaysian population (OR 2.31, 95% CI 1.12–4.73, p=0.03). The association between occupational exposure to pesticides and risk of RA was observed with ACPA-positive RA (OR 3.10 95% CI 1.49–6.47, p=0.003), but not with ACPA-negative RA. A dramatically increased risk for ACPA-positive RA was seen in individuals who both exposed to pesticides occupationally and carried SE alleles (OR 28.06, 95% CI 3.58–220.09, p<0.0001).ConclusionsThis study demonstrates that occupational exposure to pesticides is associated with an increased risk of ACPA-positive RA in Malaysian population.References[1] Sverdrup B, Källberg H, Bengtsson C, Lundberg I, Padyukov L, Alfredsson L, Klareskog L and the Epidemiological Investigation of Rheumatoid Arthritis study group. Association between occupational exposure to mineral oil and rheumatoid arthritis: results from the Swedish EIRA case–control study-Arthritis Research & Therapy2005;7:R1296-R1303.[2] Meyer A, Sandler DP, Beane Freeman LE, Hofmann JN, Parks CG. Pesticide Exposure and Risk of Rheumatoid Arthritis among Licensed Male Pesticide Applicators in the Agricultural Health Study. Environ Health Perspect2017;14;125(7):077010.Disclosure of InterestNone declared

BackgroundRecent evidence from epidemiological studies has suggested that reproductive factors may play an important role for rheumatoid arthritis (RA) development. An inverse association was reported in several studies between parity and risk of RA.ObjectivesWe investigated the association between parity and risk of anti-citrullinated peptide antibody (ACPA)-positive RA and ACPA-negative RA in the Malaysian population.MethodsData from the Malaysian Epidemiological Investigation of rheumatoid Arthritis (MyEIRA) population-based case control study involving 902 female early RA and 906 age and residential area-matched female controls were analysed. Parity history was assessed through a questionnaire. Parous women were compared with nulliparous women, by calculating odds ratio (OR) with 95% confidence intervals (Cl).ResultsOur findings demonstrated that parity was significantly associated with decreased risk of developing RA in the Malaysian population (RA versus controls, 82% vs. 89%, OR 0.58, 95% CI 0.44–0.77, p<0.001). The association between parity and risk of RA was uniformly observed for ACPA-positive RA (OR 0.58, 95% CI 0.43–0.80, p<0.001) and ACPA-negative RA (OR 0.58, 95% CI 0.40–0.84, p<0.01) subsets, respectively. Compared with nulliparous women, the decreased risk was pronounced at the level of three and more live births for both ACPA-positive (OR 0.48, 95% CI 0.34–0.66, p<0.001) and ACPA-negative RA (OR 0.46, 95% CI 0.31–0.68, p<0.001) subsets.ConclusionsOur data demonstrated that parity and level of three and more live births was associated with decreased risk of developing RA in the Malaysian population. The associated decrease risk was observed in both ACPA-positive and ACPA-negative RA subsets.References[1] Orellano C, Saevardottir S, Klareskog L, Karlson EW, Alfredsson L, Bengtsson C. Parity and the risk of developing rheumatoid arthritis: results from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. Ann Rheum Dis2014;73:752–755.[2] Ren L, Guo P, Sun Q, Liu H, Chen Y, Huang Y and Cai X. Number of parity and risk of rheumatoid arthritis in women: A dose-response meta-analysis of observational studies. J. Obstet. Gynaecol. Res2017;43(9):1428–1440.Disclosure of InterestNone declared

BackgroundAnkylosing spondylitis (AS) is a chronic spinal inflammatory disorder which leads to progressive fusion and deformity. The loss of spinal mobility is recognised as an important clinical sign. The BASMI, a composite index of spinal mobility is used internationally in clinical practice and research. However, the interpretation of BASMI has been impeded by the absence of normative values.ObjectivesWe aimed to attain the normative values for BASMI in Malaysian healthy individuals.MethodsBASMI data of 142 healthy individuals and 187 AS patients were analysed. Each BASMI component was assessed, using the 10-point scoring system, where zero is no mobility and 10 is very severe limitation. Measurements were performed by the rheumatologists and trained researchers following a designated protocol. Data were summarised and analysed according to sex and age groups.ResultsThe total BASMI scores ranged from 0.2 to 4.2 and 0.6 to 9.6 in the healthy individuals and the AS cases, respectively. There was no significant difference for the BASMI median score between healthy men and women (men=1.2, women=1.6, p>0.05). The estimated median score for healthy individuals aged 15–19 years was 1.2, increasing with age to 2.7 for healthy individuals aged ≥60 years. In AS cases, the estimated median score was 5.4 and 5.8 for men and women, respectively (p>0.05). We observed significant increase of estimated median score between AS patients aged 15–19 years (BASMI score=2.0) and AS patients aged ≥60 years (BASMI score=6.4) (p<0.05).ConclusionsOur data suggest that it is uncommon for healthy individuals to score zero on the BASMI. The magnitude of increase in BASMI score is apparent with increasing age, but not sex in the healthy individuals. Establishment of normative values may aid baseline measurement and monitor change of spinal mobility in AS patients over time, as well as help assess the impact of clinical interventions.Disclosure of InterestNone declared

BackgroundHormonal and reproductive factors are implicated in the etiology of rheumatoid arthritis (RA). The association between oral contraceptive (OC) use and the risk of RA has been reported, but the findings are inconsistent across different populations.ObjectivesWe investigated the association between OC use and risk of RA stratified by anti-citrullinated peptide antibody (ACPA) status in the Malaysian female population.MethodsData from the Malaysian Epidemiological Investigation of rheumatoid Arthritis (MyEIRA) population-based case control study involving 902 female early RA and 906 age and residential area-matched female controls were analysed. OC use data was assessed through a questionnaire. Never users of OC were compared with ever users of OC to estimate the risk of developing ACPA-positive and ACPA negative RA. The odds ratio (OR) with 95% confidence interval (CI) was calculated.ResultsIn this study, a total of 28.4% (n=254) RA cases and 34.2% (n=310) controls had reported as ever OC users. Compared with never users, ever OC users had a decreased risk of developing RA in the Malaysian population particularly in ACPA-negative RA (OR 0.68, 95% CI 0.51–0.90, p<0.001). No significant association was observed between ever OC users and ACPA-positive RA (OR 0.80, 95% CI 0.64–1.01). Further stratification analysis by duration of OC use (less than or more than 7 years versus never OC use) demonstrated significant decreased risk of developing ACPA-positive RA (OR 0.66, 95% CI 0.51–0.86, p<0.01) and ACPA-negative RA (OR 0.57, 95% CI 0.41–0.80, p<0.001), respectively.ConclusionsOral contraceptives decreased the risk of RA, particularly ACPA-negative RA in the Malaysian population. A long duration of OC use was however decreased the risk in both ACPA-positive and ACPA-negative RA subsets.References[1] Orellano C, Saevardottir S, Klareskog L, Karlson EW, Alfredsson L, Bengtsson C. Oral contraceptives, breastfeeding and the risk of developing rheumatoid arthritis: results from the Swedish Epidemiological Investigation of Rheumatoid Arthritis study. Ann Rheum Dis. 2017;76:1845–1852.[2] Adab P, Jiang CQ, Rankin E, Tsang YW, Lam TH, Barlow J, Thomas GN, Zhang WS and Cheng KK. Breastfeeding practice, oral contraceptive use and risk of rheumatoid arthritis among Chinese women: the Guangzhou Biobank Cohort Study. Rheumatology (Oxford)2014;53(5):860–6.Disclosure of InterestNone declared