Nov. 04, 2010

Low Levels of Vitamin D Are Seen With Increased Lupus Disease Activity

Serum concentrations of 25-OH vitamin D in patients with systemic lupus eryhthematosus (SLE) are inversely related to disease activity: is it time to routinely supplement patients with SLE with vitamin D?
Amital H, Szekanecz Z, Szücs G, Dankó K, Nagy E, Csépány T, Kiss E, Rovensky J, Tuchynova A, Kozakova D, Doria A, Corocher N, Agmon-Levin N, Barak V, Orbach H, Zandman-Goddard G, Shoenfeld Y. (2010).  Annals of the Rheumatic Diseases 69: 1155-1157. 

What is the topic?
Low levels of vitamin D are associated with autoimmune illnesses, especially lupus. Vitamin D is activated by a chemical reaction made possible by exposure to the sun’s ultraviolet B rays. Since people with lupus may need to avoid sun exposure, this can increase the risk for vitamin D insufficiency.   

What did the researchers hope to learn?
The researchers hoped to learn about the relationship between levels of vitamin D in the blood and lupus disease activity. 

Who was studied?
238 people with lupus from Hungary, Slovakia, Israel, and Italy were studied. They were mostly women with an average age of 40 years who had lupus for an average of about 10 years.  

How was the study conducted?
Blood samples were donated by each patient in order to determine levels of vitamin D. Lupus disease activity was determined on the same day the blood was given using an index that adds up the features of lupus that are active at a given time. 

What did the researchers find?
The researchers found that the Italian patients had significantly higher levels of vitamin D in their blood than the other patients. 

An analysis of results from all of the patients showed that higher levels of vitamin D were associated with lower lupus disease activity and patients with active disease had lower vitamin D levels than patients with inactive disease. 

What were the limitations of the study?
Vitamin D levels can be influenced by the amount of skin pigment a person has (darker skin is associated with lower vitamin D), as well as by a person’s diet and whether or not vitamin supplements are being taken. The influence of these things on the study outcome was not looked at. Also, there was limited detail about the types of lupus symptoms or blood tests that were being factored into the overall disease activity scores. 

What do the results mean for you?
The levels of vitamin D that a person has are only one of many variables that can influence lupus disease activity. In the future, it may become clearer whether vitamin D supplementation will be useful in reducing disease activity in people with lupus.