Vitamin D deficiency linked to metabolic changes in lupus patients, study finds

Patients with lupus are more likely to have metabolic syndrome and insulin resistance if they have lower vitamin D levels, according to a new study published in the journal Rheumatology.

For the study, researchers studied vitamin D levels in 1,163 patients with systemic lupus erythematosus (SLE) across 33 centers in 11 countries, including the United States, United Kingdom, Canada, Spain, The Netherlands, Sweden, Iceland, Switzerland, Turkey, South Korea, and Mexico.

The researchers found a link between lower levels of vitamin D and metabolic syndrome and insulin resistance, though further studies could confirm whether restoring vitamin D levels helps to reduce these cardiovascular risk factors and improve quality of life for patients with lupus, according to the study.

Lupus is an uncommon incurable immune system illness, more common in women, where the immune system is overactive, causing inflammation anywhere in the body. Untreated, the condition threatens irreversible damage to major organs including kidneys, heart, lungs, and brain. Metabolic syndrome is a combination of diabetes, hypertension, abnormal cholesterol levels, and obesity. People with metabolic syndrome are at greater risk of getting coronary heart disease, stroke and other conditions affecting the blood vessels, the researchers said.

The researchers said patients with SLE have an excess cardiovascular risk, up to 50 times that seen in people without the condition. This cannot be attributed to traditional cardiovascular risk factors, such as high blood pressure or smoking, alone, they said.

The mechanisms underlying the association between high blood pressure and low vitamin D in SLE are not clear, but researchers said they believe they may be linked to impact of vitamin D deficiency on the renin-angiotensin hormone system, which regulates blood pressure and fluid and electrolyte balance, as well as systemic vascular resistance.

The researchers said they believe that boosting vitamin D levels may improve control of these cardiovascular risk factors, as well as improving long-term outcomes for patients with SLE.