title: High serum cholesterol predicts rheumatoid arthritis in women, but not in men: a prospective study.
abstract: BACKGROUND
  Environmental exposures, including smoking, hormone-related factors, and metabolic factors, have been implicated in the etiology of rheumatoid arthritis (RA). A previous study has indicated that blood lipid levels may influence the development of RA. The objective of this study was to investigate the impact of serum total cholesterol and triglycerides on the risk of RA in a prospective study.
  
  
  METHODS
  Among participants in a large population-based health survey (n = 33,346), individuals who subsequently developed RA were identified by linkage to four different registers and a structured review of the medical records. In a nested case-control study, with controls, matched for age, sex, and year of inclusion, from the health survey database, the relation between serum lipids (levels of total cholesterol and triglycerides) and future RA development was examined.
  
  
  RESULTS
  In total, 290 individuals (151 men and 139 women) whose RA was diagnosed a median of 12 years (range of 1-28) after inclusion in the health survey were compared with 1160 controls. Women with a diagnosis of RA during the follow-up had higher total cholesterol levels at baseline compared with controls: odds ratio (OR) 1.54 per standard deviation; 95 % confidence interval (CI) 1.22-1.94. This association remained statistically significant in multivariate models adjusted for smoking and a history of early menopause and in analyses stratified by rheumatoid factor status and time to RA diagnosis. Total cholesterol had no significant impact on the risk of RA in men (OR 1.03; 95 % CI 0.83-1.26). Triglycerides did not predict RA in men or women.
  
  
  CONCLUSIONS
  A high total cholesterol was a risk factor for RA in women but not in men. This suggests that sex-specific exposures modify the impact of lipids on the risk of RA. Hormone-related metabolic pathways may contribute to RA development.
authors.affiliation: Rheumatology, Department of Clinical Sciences, Malmö, Lund University, Inga-Marie Nilssons gata 32, Malmö, 205 02, Sweden. carl.turesson@med.lu.se.|Department of Rheumatology, Skåne University Hospital, Inga-Marie Nilssons gata 32, 205 02, Malmö, Sweden. carl.turesson@med.lu.se.
authors.forename: Carl
authors.initials: C
authors.lastname: Turesson
authors.affiliation: Rheumatology, Department of Clinical Sciences, Malmö, Lund University, Inga-Marie Nilssons gata 32, Malmö, 205 02, Sweden. pwf626s@tninet.se.|Department of Rheumatology, Skåne University Hospital, Inga-Marie Nilssons gata 32, 205 02, Malmö, Sweden. pwf626s@tninet.se.
authors.forename: Ulf
authors.initials: U
authors.lastname: Bergström
authors.affiliation: Rheumatology, Department of Clinical Sciences, Malmö, Lund University, Inga-Marie Nilssons gata 32, Malmö, 205 02, Sweden. mitra.pikwer@med.lu.se.|Department of Rheumatology, Eskilstuna Hospital, Kungsvägen 34, Eskilstuna, 631 88, Sweden. mitra.pikwer@med.lu.se.
authors.forename: Mitra
authors.initials: M
authors.lastname: Pikwer
authors.affiliation: Rheumatology, Department of Clinical Sciences, Malmö, Lund University, Inga-Marie Nilssons gata 32, Malmö, 205 02, Sweden. jan-ake.nilsson@med.lu.se.|Department of Rheumatology, Skåne University Hospital, Inga-Marie Nilssons gata 32, 205 02, Malmö, Sweden. jan-ake.nilsson@med.lu.se.
authors.forename: Jan-Åke
authors.initials: JÅ
authors.lastname: Nilsson
authors.affiliation: Rheumatology, Department of Clinical Sciences, Malmö, Lund University, Inga-Marie Nilssons gata 32, Malmö, 205 02, Sweden. lennart.jacobsson@med.lu.se.|Department of Rheumatology and Inflammation Research, The Sahlgrenska Academy, University of Gothenburg, Guldhedsgatan 10, Gothenburg, 413 46, Sweden. lennart.jacobsson@med.lu.se.
authors.forename: Lennart Th
authors.initials: LT
authors.lastname: Jacobsson
mesh_terms: D000328:Adult; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000097:blood* / Q000150:complications*; D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood*; D005260:Female; D006801:Humans; D006937:Hypercholesterolemia / Q000150:complications*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012307:Risk Factors; D012737:Sex Factors; D014280:Triglycerides / Q000097:blood
chemical_list: D014280:Triglycerides; D002784:Cholesterol