Vitamin D and systemic lupus erythematosus: an update

Osteoporosis in rheumatic diseases

Rheumatic diseases, characterized by chronic inflammation and damage to various organs and systems, include systemic lupus erythematosus, rheumatoid arthritis, ankylosing spondylitis and other connective tissue diseases. Bone is a target in many inflammatory rheumatic diseases. In recent years, the survival of patients with rheumatic diseases has increased markedly and the relationship between rheumatic diseases and osteoporosis (OP) has become more prominent. OP and related fragility fractures increase the morbidity and mortality of rheumatic disease. The cause of OP in rheumatic diseases is complex. The pathogenesis of OP in rheumatic diseases is multifactorial, including disease and treatment-related factors. Osteoimmunology, a crosstalk between inflammatory and bone cells, provides some insight into the pathogenesis of bone loss in systematic inflammatory diseases. The aim of this article is to review different risk factors in rheumatic diseases. Several factors play a role, such as chronic inflammation, immunological factors, traditional factors, metabolism and drug factors. Chronic inflammation is the most important risk factor and drug treatment is complex in patients with OP and rheumatic disease. Attention should be paid to bone loss in rheumatic disease. Optimal treatment of the underlying rheumatic disease is the first step towards prevention of OP and fractures. Apart from that, a healthy lifestyle is important as well as calcium and vitamin D supplementation. Bisphosphonates or denosumab might be necessary for patients with a low T score.

Increased serum fibroblast growth factor-23 and decreased bone turnover in patients with systemic lupus erythematosus under treatment with cyclosporine and steroid but not steroid only

SUMMARY

In patients with systemic lupus erythematosus (SLE), low bone mineral density (BMD) is associated with increased age, prolonged disease, low body mass index (BMI), and overlap with rheumatoid arthritis (RA). Elevated fibroblast growth factor (FGF)-23 in cyclosporine A (CsA) users with SLE are associated with decreased active vitamin D and osteocalcin.

INTRODUCTION

The objective of this study was to investigate the steroid and CsA effect on bone metabolism and serum FGF-23 in SLE patients.

METHODS

Seventy-two SLE patients and 10 age- and sex-matched healthy individuals underwent blood tests for bone metabolic biomarkers and FGF-23, and lumbar spine dual-energy X-ray absorptiometry for BMD.

RESULTS

Comparisons between patients and controls were made in premenopausal women/men younger than 50 years and postmenopausal women/men older than 50 years separately. SLE patients had more frequent low Z-score (≤-2.0, 8.5 vs. 0%), osteopenia (-2.5<T-score<-1.0, 52 vs. 50%), and osteoporosis (T-score≤-2.5, 12 vs. 0%), than the healthy age-compatible counterparts. BMD was significantly lower in patients with advanced age, longer disease duration, lower BMI, and overlap with RA (all p<0.05 by multiple linear regression analyses). Serum FGF-23 was significantly higher and 1,25-dihydroxyvitamin D (1,25(OH)2D3) lower in SLE patients treated with glucocorticoid and CsA than in those not taking both of them (p=0.027 and 0.002, respectively). The cumulative dose of glucocorticoid was inversely correlated with serum intact parathyroid hormone (r=-0.299, p=0.011), C-terminal telopeptide of type I collagen (r=-0.581, p<0.001), and osteocalcin (r=-0.648, p<0.001). FGF-23 and the cumulative dose of CsA were positively correlated (r=0.38, p=0.001) and both were negatively correlated with 1,25(OH)2D3 (r=-0.266, p=0.016 and r=-0.55, p<0.001) and osteocalcin (r=-0.234, p=0.034 and r=-0.274, p=0.02).

CONCLUSION

SLE patients treated with glucocorticoid and CsA exhibited markedly decreased bone turnover. Those taking CsA had higher serum FGF-23 associated with suppression of 1,25(OH)2D3 and bone formation. Such high-risk patients necessitate regular screening of osteoporosis.

Vitamin D status in children with systemic lupus erythematosus and its association with clinical and laboratory parameters

To assess serum 25-hydroxyvitamin D (25-OH vitamin D) status in Saudi children with systemic lupus erythematosus (SLE) and determined its association with clinical, laboratory variables and disease activity. This cross-sectional study comprised children with SLE who are followed at Pediatric Lupus Clinic. All patients reviewed for demographic data, age of first disease manifestations, and disease duration. All included patients evaluated for disease activity, which is completed by using the SLE Disease Activity Index (SLEDAI) and laboratory parameters included a vitamin D profile, bone markers at enrollment and 3 months later. All patients treated with Cholecalciferol (vitamin D3 2000 IU daily) and calcium supplement (Caltrate 600 mg twice daily). Twenty-eight patients (26 female) with mean age of 9.7 years completed the evaluation. Fifteen patients had more than one major organ involvement. Most of the patients are on daily vitamin D3 supplement (800 IU) prior enrollment. The baseline assessment revealed 24 patients had low levels of serum 25-OH vitamin D levels, with a mean of 51.1 ± 33.6 nmol/L; 25 patients had high autoantibodies; and 18 patients had high protein/creatinine ratio, with a mean of 0.9 ± 1.7. Bone density was subnormal with a mean of 0.9 ± 1. The mean disease activity was 6 ± 5.6. Levels of 25-OH vitamin D correlated inversely with autoantibodies and SLEDAI and positively with bone density but not statistically significant. After 3 months, treatment of vitamin D3 (2000 IU daily) and Caltrate (600 mg twice daily), 17 patients had improvement in SLEDAI score and autoimmune markers. Disease activity of childhood SLE is probably linked with low serum 25-OH vitamin D levels. Accordingly, high daily vitamin D3 supplement could potentially impact disease activity of childhood SLE. Further follow up and more patients needed to confirm this finding.

Sleep disorders in systemic lupus erythematosus. Does vitamin D play a role?

Objectives

Sleep disorders are common among patients with systemic lupus erythematosus (SLE) with unclear underlying mechanisms. We assessed the role of vitamin D in sleep quality of patients with SLE.

Methods

A retrospective study was conducted on women with SLE for whom the following data were available at the same time; sleep quality (Pittsburgh Sleep Quality Index (PSQI)), disease activity, cumulative disease damage, psychological state (Hospital Anxiety and Depression Scale (HADS)), and serum vitamin D level. Bivariate and regression analyses were computed to find contributors of sleep quality.

Results

In total, 63 women were studied. Serum vitamin D level was correlated with physical activity ( r = 0.310, p = 0.015), season of assessment ( r = −0.302, p = 0.016), the PSQI global score ( r = −0.262, p = 0.043), anxiety score ( r = −0.298, p = 0.021), and non-significantly with depression score ( r = −0.218, p = 0.094). Including all variables into a linear regression model, vitamin D level was independently associated with the global PSQI score (beta = −0.364, p = 0.042). Association of vitamin D level with psychological state disappeared after controlling for season of assessment (beta = −0.248, p = 0.154).

Conclusions

We found a role for vitamin D in sleep quality of SLE patients. Further studies are warranted to confirm these results and to find possible mechanisms of action.

Vitamin D and cutaneous lupus erythematosus: effect of vitamin D replacement on disease severity

BACKGROUND

The main vitamin D source is exposure to ultraviolet radiation, which aggravates cutaneous lupus erythematosus (CLE).

OBJECTIVES

The aims of this study were to identify variables associated with lower serum 25-hydroxyvitamin D [25(OH)D] levels in CLE patients and assess the effect of vitamin D restoration on disease severity.

METHODS

Vitamin D status in 60 CLE patients and 117 apparently healthy subjects was compared. We recommended oral vitamin D3 to 27 CLE patients. After one year of treatment, changes in disease severity were assessed and compared to 25 untreated CLE patients. Disease severity was measured by the Cutaneous Lupus Erythematosus Disease Area and Severity Index (CLASI), number of exacerbations, duration of active lesions and patient assessment.

RESULTS

Presence of CLE raised the odds of having vitamin D deficiency (OR 3.47, 95% CI 1.79-6.69). Increasing age and disease duration were associated with higher odds of having vitamin D deficiency. After a one-year follow-up, disease activity improved in the treatment group (CLASI A 2.7 ± 2.9 vs. 0.9 ± 1.4) (p = 0.003), as confirmed by the patient assessment (p = 0.01).

CONCLUSIONS

Vitamin D inadequacy is more prevalent in CLE participants than in healthy controls. Treating vitamin D insufficiency is associated with improved disease severity according to physician and patient assessments.

Vitamin D receptor (VDR) gene polymorphisms and susceptibility to systemic lupus erythematosus clinical manifestations

Systemic lupus erythematosus (SLE) is an autoimmune disorder with heterogeneous clinical manifestations and target tissue damage. Currently, several genes have been associated with SLE susceptibility, including vitamin D receptor (VDR), which is a mediator of immune responses through the action of vitamin D. Polymorphisms in the VDR gene can impair the vitamin D (D3) function role, and since SLE patients show deficient D3 blood levels, it leads to a possible connection to the disease's onset. In our study we searched for an association between VDR polymorphisms and risk of developing SLE, as well as the disease's clinical manifestations. We enrolled 158 SLE patients and 190 Southeast Brazilian healthy controls, genotyped for five Tag single nucleotide polymorphisms (SNPs), covering most of the VDR gene region. We found an association between VDR SNPs and SLE for the following clinical manifestations: rs11168268 and cutaneous alterations (p=0.036), rs3890733 (p=0.003) rs3890733 and arthritis (p=0.001), rs2248098 and immunological alterations (p=0.040), rs4760648 and antibody anti-dsDNA (p=0.036). No association was reported between VDR polymorphisms and SLE susceptibility.