Childbirth increases risk of ACPA-negative rheumatoid arthritis

(Press-News.org) Madrid, Spain, 13 June 2013: Epidemiological data presented today at EULAR 2013, the Annual Congress of the European League Against Rheumatism, demonstrate that pregnancy carried to childbirth (parity) increases the risk of ACPA-negative* rheumatoid arthritis (RA).

The increased risk was demonstrated in women aged 18-44 who have had a child (2.1, 95% CI 1.4-3.2), but not in older women, and was more pronounced among those women with delivery during the first year of symptoms.

RA is an autoimmune disease characterised by inflammation of the joints and tendons. As a chronic condition, RA can cause pain, stiffness, progressive joint destruction and deformity, and reduce physical function, quality of life and life expectancy. Prevalence varies between 0.3% and 1%, with the disease more common in women than men.

"It has been suggested that the risk of RA is decreased during pregnancy but increased after delivery. Our data demonstrates that the increased risk after delivery is only associated with ACPA-negative RA and not ACPA-positive RA."

"Our findings of different impact of parity history on the two subgroups of RA add further evidence to the notion that RA comprises two different disease entities with different aetiology," said lead author of the study Cecilia Orellana, Institute of Environmental Medicine, Karolinska Institutet, Karolinska University, Stockholm, Sweden.

The Swedish population-based EIRA (Epidemiological Investigation of RA) case-control study was comprised of 2,035 female cases aged 18-70, and 2,911 matched controls collected between 1996 and 2009. Parity, post-partum period before onset of symptoms and age at first birth were assessed by means of a questionnaire.

"Further studies are needed to fully explore the biological mechanisms behind our findings, but reproductive factors may partly explain the notoriously higher incidence of RA among women" Ms Orellana concluded.

### * ACPA, anti-citrullinated protein antibody; specific and sensitive diagnostic marker for RA which can be detected years before the first clinical manifestation of RA. ACPA-positive and ACPA-negative disease are associated with different genetic and environmental risk factors, fuelling hypotheses of different underlying pathophysiology.2

1.Orellana C et al., The association between parity and rheumatoid arthritis: results from the Swedish EIRA study [abstract]. EULAR Annual European Congress of Rheumatology; 12-15 June 2013; Madrid, Spain. Abstract nr. OP0149. 2.Willemze A, Böhringer S, Knevel R, et al. Ann Rheum Dis (2011). doi:10.1136/annrheumdis-2011-200421

NOTES TO EDITORS:

For further information on this study, or to request an interview with the study lead, please do not hesitate to contact the EULAR congress Press Office in room A10:14 of the Congress Centre during EULAR 2013 or on: Email: eularpressoffice@cohnwolfe.com EULAR Press Office Onsite tel: +44 (0) 20 7331 5364 / 5380 / 5318 / 2305

About EULAR

The European League Against Rheumatism (EULAR) is an umbrella organisation which represents scientific societies, health professional associations and organisations of people with rheumatic diseases throughout Europe In line with the European Union of Medical Specialists (UEMS), EULAR defines rheumatology as including rheumatic diseases of the connective tissue, locomotor and musculoskeletal systems. EULAR aims to promote, stimulate and support the research, prevention, treatment and rehabilitation of rheumatic diseases With 45 scientific member societies, 36 People with Arthritis and Rheumatism in Europe (PARE) organisations and 11 health professionals associations, EULAR underscores the importance of combating rheumatic diseases not only through medical means, but also through patient care EULAR 2013 is set to be the biggest rheumatology event in Europe with over 14,000 scientists, physicians, allied health professionals and related audiences in attendance from more than 110 countries. Over the course of the congress there will be more than 320 oral and 1,800 poster abstract presentations, and 750 lectures with 330 invited speakers To find out more about the activities of EULAR, visit: http://www.eular.org