Association between work physical activity, dietary factors, and risk of rheumatoid arthritis.

OBJECTIVE

We aimed to determine the association of physical activity and dietary factors on RA risk.

METHODS

This case-control study within the Mayo Clinic Biobank matched incident RA cases (two codes plus disease-modifying anti-rheumatic drug, PPV 95%) to controls 1:3 on age, sex, and recruitment year/location. A baseline questionnaire assessed activity and dietary exposures. Logistic regression models calculated adjusted odds ratios (aOR) with 95% confidence intervals (CI) of RA for each of 45 activity/dietary exposures.

RESULTS

We identified 212 incident RA cases and 636 controls (mean age 64, 70% female). Active work physical activity was associated with elevated risk of RA (aOR 3.00, 95% CI 1.58-5.69 vs. sedentary); leisure activity was not (aOR 0.96, 95% CI 0.64-1.42 sedentary vs. active). Three or more servings high-fat food and 5+ servings fruits/vegetables daily showed non-significant associations with RA (aOR 1.22, 95% CI 0.74-2.00 vs. 0-1 time; aOR 0.75, 95% CI 0.51-1.11 vs. 0-3 times), especially in sensitivity analyses with at least five years between questionnaire and RA (aOR 1.80, 95% CI 0.69-4.71; aOR 0.54, 95% CI 0.27-1.08). Alcohol binging was not associated with RA risk (aOR 1.28, 95% CI 0.56-2.96). Finally, sensitivity (versus primary) analyses showed a nonsignificant increase in RA risk for most vitamins and supplements.

CONCLUSION

Active work physical activity and some nutritional profiles (increased high-fat, reduced fruit/vegetable consumption) may be associated with increased risk of RA. Confirmatory studies are needed.