Association between Vitamin D deficiency and antinuclear antibodies in middle-aged and older U.S. adults

Background: Vitamin D deficiency is associated with cancer and autoimmune diseases, but little is known about the association between vitamin D and antinuclear antibodies (ANA), a biomarker of immune dysfunction in healthy populations. The objective of this study was to determine whether vitamin D deficiency is associated with ANA in middle-aged and older U.S. adults. Methods: A cross-sectional analysis using the National Health and Nutrition Examination Survey (NHANES) 2001-2004 was conducted. Data were available for 1,012 adults aged 50 years and older. Serum 25-hydroxyvitamin D levels were measured by radioimmunoassay. ANA was measured in a 1:80 dilution of sera by immunofluorescence using HEp-2 cells (seropositive ¼ 3 or 4þ). Results: Greater vitamin D deficiency was associated with higher ANA prevalence in the unadjusted (P_trend ¼ 0.0002) logistic regression model and after adjustment for sex, age, education, race/ethnicity, season, and NHANES cycle (P_trend ¼ 0.04). After adjustment, those with severe vitamin D deficiency (<10 ng/mL) had 2.99 (95% CI, 1.25-7.15) times the odds of ANA compared with having normal vitamin D levels (30 ng/mL), while deficient and insufficient individuals had twice the odds of ANA. Conclusions: Among U.S. residents ages 50 and older, vitamin D deficiency was associated with higher prevalence of ANA. Vitamin D sufficiency may be important for preventing immune dysfunction in older populations. Impact: Our findings support the growing evidence that vitamin D is an important immune modulator. Vitamin D deficiency in older adults may increase vulnerability to cancer by contributing to immune dysfunction. Cancer Epidemiol Biomarkers Prev; 25(12); 1559-63. 2016 AACR.