title: Growth and infectious exposure during infancy and the risk of rheumatoid factor in adult life.
abstract: BACKGROUND
  The contribution of the environment to rheumatoid arthritis (RA) remains uncertain. Intrauterine and early postnatal life may be important. Rheumatoid factor (RF) found in around 10% of the normal population confers a risk of developing RA and may be present years before onset of clinical disease. The immune pathology leading to RA and RF may have similar genetic and environmental influences.
  
  
  OBJECTIVE
  To measure RF in people for whom data on birth weight, infant growth, and markers of infectious exposure during infancy and childhood, had been previously recorded.
  
  
  METHODS
  675 men and 668 women aged 59-67 years, born and still resident in Hertfordshire, UK, were studied. RF was measured with an ELISA. Associations between presence of RF, early growth, and markers of hygiene in infancy, were investigated.
  
  
  RESULTS
  RF was detected in 112/675 (16.6%) men and 79/668 (11.8%) women. No significant relationships existed between early growth and presence of RF in men or women. Among women, sharing a bedroom during childhood was associated with a lower risk of RF positivity (OR = 0.48, 95% CI 0.30 to 0.78, p = 0.003).
  
  
  CONCLUSIONS
  A developing immune system exposed to increased infectious exposure is less likely to produce RF in adult life; this may reduce the pathological process which leads to RA.
authors.affiliation: Department of Rheumatology, Southampton General Hospital, Tremona Road, Southampton SO16 6YD, UK. cedwards@soton.ac.uk
authors.forename: C J
authors.initials: CJ
authors.lastname: Edwards
authors.forename: R
authors.initials: R
authors.lastname: Goswami
authors.forename: P
authors.initials: P
authors.lastname: Goswami
authors.forename: H
authors.initials: H
authors.lastname: Syddall
authors.forename: E M
authors.initials: EM
authors.lastname: Dennison
authors.forename: N K
authors.initials: NK
authors.lastname: Arden
authors.forename: C
authors.initials: C
authors.lastname: Cooper
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000209:etiology / Q000276:immunology / Q000517:prevention & control; D001722:Birth Order; D001724:Birth Weight; D003141:Communicable Diseases / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006128:Growth; D006798:Housing; D006801:Humans; D006920:Hygiene; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008875:Middle Aged; D012217:Rheumatoid Factor / Q000097:blood*; D012307:Risk Factors; D012923:Social Class; D018709:Statistics, Nonparametric
chemical_list: D012217:Rheumatoid Factor