title: High Sodium Intake Is Associated With Self-Reported Rheumatoid Arthritis: A Cross Sectional and Case Control Analysis Within the SUN Cohort.
abstract: Sodium intake is a potential environmental factor for immune-mediated inflammatory diseases. The aim of this study is to investigate the association of sodium intake with rheumatoid arthritis. We performed a cross-sectional study nested in a highly educated cohort investigating dietary habits as determinants of disease. Daily sodium intake in grams per day was estimated from a validated food frequency questionnaire. We identified prevalent self-reported cases of rheumatoid arthritis. Logistic regression models were used to estimate the odds ratio for rheumatoid arthritis by sodium intake adjusting for confounders. Linear trend tests and interactions between variables were explored. Sensitivity analyses included age- and sex-matched case-control study, logistic multivariate model adjusted by residuals, and analysis excluding individuals with prevalent diabetes or cardiovascular disease. The effective sample size was 18,555 individuals (mean age 38-years old, 60% women) including 392 self-reported rheumatoid arthritis. Median daily sodium intake (estimated from foods plus added salt) was 3.47 (P25-75: 2.63-4.55) grams. Total sodium intake in the fourth quartile showed a significant association with rheumatoid arthritis (fully adjusted odds ratio 1.5; 95% CI 1.1-2.1, P for trend = 0.02). Never smokers with high sodium intake had higher association than ever smokers with high sodium intake (P for interaction = 0.007). Dose-dependent association was replicated in the case-control study. High sodium intake may be associated with a diagnosis of rheumatoid arthritis. This confirms previous clinical and experimental research.
authors.affiliation: From the Rheumatology Unit, Complejo Hospitalario Universitario de Santiago de Compostela, IDIS Ramon Dominguez, Santiago, A Coruña (ES, LC, JJG-R); Rheumatology Unit, Complejo Hospitalario Universitario de Ourense, Ourense (ES); Department of Preventive Medicine and Public Health, School of Medicine, University of Navarra, Pamplona, Navarra (MB-R, JDI); Instituto de Salud Musculoesquelética; Universidad Camilo José Cela, Madrid (LC); and Department of Medicine, School of Medicine, Universidad de Santiago de Compostela, A Coruña, Spain (JJG-R).
authors.forename: Eva
authors.initials: E
authors.lastname: Salgado
authors.forename: Maira
authors.initials: M
authors.lastname: Bes-Rastrollo
authors.forename: Jokin
authors.initials: J
authors.lastname: de Irala
authors.forename: Loreto
authors.initials: L
authors.lastname: Carmona
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Gómez-Reino
mesh_terms: D000328:Adult; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000209:etiology*; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D012982:Sodium, Dietary / Q000009:adverse effects*
chemical_list: D012982:Sodium, Dietary