Vitamin D Deficiency Linked to Metabolic Changes in Lupus Patients

Metabolic syndrome is a cluster of conditions that occur together, increasing the risk of heart disease, stroke and type 2 diabetes. These conditions include increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels. Metabolic syndrome is increasingly common, and up to one-third of adults in the USA have it.

A large team of immunologists and their international colleagues working with the University of Birmingham (Birmingham, UK) examined vitamin D levels in 1,163 patients with SLE across 33 centers in 11 countries. Clinical, laboratory and therapeutic data were collected. Vitamin D level was defined according to tertiles based on distribution across this cohort, which were set at T1 (10–36 nmol/L), T2 (37–60 nmol/L) and T3 (61–174 nmol/L). Metabolic syndrome was defined according to the 2009 consensus statement from the International Diabetes Federation. Insulin resistance was determined using the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) model. Linear and logistic regressions were used to assess the association of variables with vitamin D levels.

The team reported that of the 1,847 patients, 1,163 (63%) had vitamin D measured and 398 (34.2%) subjects were in the lowest 25(OH)D tertile. Metabolic syndrome was present in 286 of 860 (33%) patients whose status could be determined. Patients with lower 25(OH)D were more likely to have metabolic syndrome and higher HOMA-IR. The metabolic syndrome components, hypertension, hypertriglyceridemia and decreased high-density lipoprotein (HDL) were all significantly associated with lower 25(OH)D. Increased average glucocorticoid exposure was associated with higher insulin resistance.

John A. Reynolds, MD, a Consultant Rheumatologist and a senior author of the study. said, “Our results suggest that co-existing physiological abnormalities may contribute to long-term cardiovascular risk early on in systemic lupus erythematosus. We found a link between lower levels of vitamin D and metabolic syndrome and insulin resistance.”

The authors concluded that metabolic syndrome and insulin resistance are associated with lower vitamin D in patients with SLE. Further studies could determine whether vitamin D repletion confers better control of these cardiovascular risk factors and improve long-term outcomes in SLE. The study was published originally published on February 8, 2021 in the journal Rheumatology.

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