Association of dietary sodium intake with IL-17-mediated diseases in the UK Biobank.

BACKGROUND & AIMS: IL-17-mediated diseases have great global burden. Basic science research suggests that excessive sodium intake can trigger systemic IL-17-mediated inflammation, but population-based data on the association between sodium intake and IL-17-mediated diseases are limited. We aim to understand if increased estimated dietary sodium is associated with higher rates of IL-17-mediated disease. METHODS: We conducted a population-based cross-sectional study using UK Biobank data from 468,673 participants (aged 37-73 years) recruited between March 2006 and October 2010. The exposure, dietary sodium, was estimated using the International Study of Electrolyte Secretion and Blood Pressure equation. The main outcome, prevalence of any IL-17-mediated disease (psoriasis, psoriatic arthritis, ankylosing spondylitis, hidradenitis suppurativa, systemic lupus erythematosus, rheumatoid arthritis, inflammatory bowel disease, multiple sclerosis), was determined by diagnostic codes. RESULTS: After adjusting for age, sex, ethnicity, Townsend deprivation index, and education, a 1-gram higher estimated daily sodium intake was associated with higher odds of having an IL-17-mediated disease (adjusted odds ratio [aOR] 1.08, 95% confidence interval [CI] 1.06 to 1.10) as well as more IL-17-mediated diseases (adjusted rate ratio 1.08, 95% CI 1.06 to 1.10). Sub-analyses of individual diseases showed that higher estimated dietary sodium was associated with higher odds of psoriasis (aOR 1.17, 95% CI 1.13 to 1.22), psoriatic arthritis (aOR 1.22, 95% CI 1.13 to 1.32), hidradenitis suppurativa (aOR 2.07, 95% CI 1.73 to 2.47), and rheumatoid arthritis (aOR 1.19, 95% CI 1.14 to 1.24), and lower odds of having inflammatory bowel disease (aOR 0.84, 95% CI 0.80 to 0.88). There was no significant association with ankylosing spondylitis (aOR 1.00, 95% CI 0.93 to 1.08), systemic lupus erythematosus (aOR 0.93, 95% CI 0.69 to 1.26), or multiple sclerosis (aOR 0.95, 95% CI 0.81 to 1.12). CONCLUSION: In a large population-based cohort, higher estimated dietary sodium was associated with a small increase in the odds of IL-17-mediated disease, particularly those of the skin and joints. Future work should investigate whether a low-salt diet improves IL-17-mediated diseases.