The Daily Intake Levels of Copper, Selenium, and Zinc Are Associated with Osteoarthritis but Not with Rheumatoid Arthritis in a Cross-sectional Study

Yang WM, Lv JF, Wang YY, et al. · Biological Trace Element Research

Higher daily zinc intake was independently associated with INCREASED odds of osteoarthritis (with a trend toward higher OA odds at higher intake), while serum zinc did not differ between groups — an observational signal pointing the opposite way from the OAI intake study.

Population

US adults in NHANES 2011-2016, classified as non-arthritis, OA or RA

Intervention

Daily zinc (and copper, selenium) intake and serum levels; no supplementation

Comparator

Lower intake

Limitations

Cross-sectional, so reverse causation and diet-pattern confounding are live; self-reported arthritis; abstract-level appraisal (full text paywalled) — direction of association is stated in the paper's own conclusions.