The association between dietary zinc intake and osteopenia, osteoporosis in patients with rheumatoid arthritis.

Background: Diet has been shown to be associated with rheumatoid arthritis (RA), of which osteoporosis is the most common and important complication, and zinc has been shown to inhibit the inflammatory response, but studies on the relationship between dietary zinc and osteoporosis in patients with RA are limited and inconclusive. In this study, we aimed to explore the relationship between dietary zinc intake and osteoporosis or osteopenia in patients with RA.

Methods: Data on RA patients were derived from the National Health and Nutrition Examination Survey (NHANES) 2007 to 2010, 2013 to 2014, and 2017 to 2020. Weighted univariate and multivariate logistic regression models were performed to explore the association between dietary zinc intake and osteoporosis or osteopenia in RA patients. The relationship was further investigated in different age, body mass index (BMI), nonsteroidal use, dyslipidemia, diabetes, and hypertension population. All results were presented as odds ratios (ORs) and confidence intervals (CIs).

Results: In total, 905 RA patients aged ≥ 40 years were included. After adjusting all covariates, higher dietary zinc intake was associated with lower odds of osteopenia or osteoporosis (OR = 0.39, 95%CI: 0.18-0.86) in RA patients. The relationship between dietary zinc intake ≥ 19.52 mg and lower odds of osteopenia or osteoporosis were also found in those aged ≥ 60 years (OR = 0.38, 95%CI: 0.16-0.91), BMI normal or underweight (OR = 0.16, 95%CI: 0.03-0.84), nonsteroidal use (OR = 0.14, 95%CI: 0.02-0.82), dyslipidemia (OR = 0.40, 95%CI: 0.17-0.92), diabetes (OR = 0.37, 95%CI: 0.14-0.95), and hypertension (OR = 0.37, 95%CI: 0.16-0.86).

Conclusion: Higher dietary zinc intake was associated with reduced incidence of osteopenia or osteoporosis in patients with RA. Further longitudinal and randomized trials are necessary to validate our findings and explore the underling mechanisms. Adequate dietary zinc intake may beneficial to the bone health in RA patients.