title: Ageing: a risk factor for amyloid A amyloidosis in rheumatoid arthritis.
abstract: OBJECTIVE
  Acceleration of amyloid A (AA) amyloidosis induction by ageing has not been extensively studied in rheumatoid arthritis (RA). The aim of this study is to clarify contribution of ageing to the development of AA amyloidosis associated with RA in our large cohort.
  
  
  METHODS
  388 adult-onset RA patients whose RA was complicated by biopsy-proven AA amyloidosis were enrolled. The ages of RA onset and AA amyloidosis diagnosis were estimated in each patient. The contributions of ageing, inflammatory activity, SAA1 exon 3 polymorphism as well as gender to the pathogenesis of AA amyloidosis in 144 cases were also studied by multiple regression analysis.
  
  
  RESULTS
  Subjects with RA onset at older age had a shorter period to develop amyloidosis than those with disease onset at younger age (p < 0.001). The interval between RA onset and AA amyloidosis diagnosis was significantly shorter in the SAA1.3 positive group than in the SAA1.3 negative (p=0.001). Multiple regression analysis indicated that the interval from RA onset to diagnosis of AA amyloidosis is determined by age at RA onset (p < 0.001), the most recent median annual CRP concentration (p=0.006) and SAA1.3 allele (p=0.058). Gender did not significantly contribute to the onset of AA amyloidosis (p=0.569).
  
  
  CONCLUSIONS
  Ageing is an independent risk factor for the induction of AA amyloidosis complicating RA.
authors.affiliation: Department of Internal Medicine, Center for Rheumatic Diseases, Dohgo Spa Hospital, 21 -21 Otsu Dohgo-Himezuka Matsuyama-City, Ehime, Japan. yaokuda@ehime.med.or.jp
authors.forename: Yasuaki
authors.initials: Y
authors.lastname: Okuda
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Yamada
authors.forename: Masaaki
authors.initials: M
authors.lastname: Matsuura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Takasugi
authors.forename: Makoto
authors.initials: M
authors.lastname: Goto
mesh_terms: D000375:Aging / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D000483:Alleles; D000686:Amyloidosis / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D001172:Arthritis, Rheumatoid / Q000150:complications* / Q000235:genetics / Q000378:metabolism; D015331:Cohort Studies; D005091:Exons; D005838:Genotype; D006801:Humans; D011110:Polymorphism, Genetic; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D000685:Serum Amyloid A Protein / Q000235:genetics / Q000378:metabolism*; D012737:Sex Factors
chemical_list: C521404:SAA1 protein, human; D000685:Serum Amyloid A Protein