The immune system creates an abundance of antibodies, which are specific types of proteins that identify and combat foreign invaders, such as bacteria or viruses. However, in cases when the immune system becomes dysfunctional, the body’s own healthy cells are mistaken for foreign matter, resulting in the creation of auto-antibodies. These auto-antibodies attack healthy tissue, resulting in inflammation and pain.
Antinuclear antibodies (ANA) are a specific type of antibody that targets the body’s naturally occurring proteins within the nucleus of a cell. High concentrations of auto-antibodies, including ANA, may indicate the presence of an autoimmune disease. Common autoimmune conditions with elevated ANA levels include but are not limited to Lupus, scleroderma, autoimmune hepatitis, immune-mediated chronic infections and cancer.
Vitamin D plays a role in both the innate (immediate) and adaptive (antibody) immune responses by influencing the regulation of T cells and B cells. T cells suppress reactions of other immune cells, which is crucial in preventing autoimmunity, while the B cells are responsible for producing antibodies. In the case of vitamin D deficiency, B cells may become hyperactive and T cell regulation is decreased, potentially resulting in elevated serum ANA.
Despite the known relationship between vitamin D and the immune system, including conditions such as lupus and cancer, there is a lack of research regarding the relationship between vitamin D and ANA. Therefore, researchers recently aimed to determine whether vitamin D deficiency is associated with the presence of ANA in the US population.
The researchers observed data from NHANES, a population based survey used to assess the health of the US population. The 2001-2002 and 2003-2004 NHANES cycles included a measurement of both serum vitamin D levels and ANA. Individuals were included in the analysis if they were at least 50 years of age and included adequate covariate information. In all, a total of 1,012 participants were included in the analysis.
The researchers measured the ANA levels and serum 25(OH)D status. Vitamin D status was considered deficient if levels were <10 ng/ml, insufficient when levels were between 20-29.9 ng/ml and sufficient when levels were at least 30 ng/ml. The participants’ demographic, physical activity and biometric data were also observed.
Here is what the researchers found:
- Vitamin D deficiency was associated with an elevated ANA (P = 0.002).
- This relationship remained significant after adjusting for cofactors (P = 0.04).
- Those with severe vitamin D deficiency (< 10 ng/ml) experienced a 2.99 fold increased odds of a positive ANA compared to those with sufficient vitamin D levels (> 30ng/ml).
- Individuals with vitamin D levels between 10 ng/ml and 29 ng/ml were twice as likely to have a positive ANA compared to those with normal vitamin D levels.
The researchers concluded,
“Among U.S. residents aged 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.”
This is the first study to examine the role of vitamin D and ANA in a large, US representative sample. The study’s findings further validate the growing evidence supporting the role of vitamin D in immune function. However, due to its observational design, the researchers were unable to prove a causal relationship between vitamin D and ANA. Furthermore, because NHANES does not include the institutionalized elderly, who are at an increased risk for vitamin D deficiency, the researchers believe that their results may have underestimate this relationship.
The authors went on to state,
“Prospective studies on ANA incidence in healthy aging individuals, including longitudinal data on vitamin D, are warranted and may reveal pathways by which vitamin D deficiency may contribute to the development of autoimmunity, a potential immunologic biomarker of cancer.”
Sturges, M. & Cannell, JJ. Low vitamin D status associated with presence of autoantibodies linked with autoimmunity and cancer. The Vitamin D Council Blog & Newsletter, 2016.