Vitamin D deficiency does not increase the risk of rheumatoid arthritis: comment on the article by Merlino et al

Vitamin D status and risk of rheumatoid arthritis: systematic review and meta-analysis

BACKGROUND

Vitamin D is important for immunomodulation and may play a role in autoimmune diseases. Studies have reported a high prevalence of vitamin D deficiency in rheumatoid arthritis (RA) patients, and vitamin D status, assessed by circulating 25-hydroxyvitamin D [25(OH)D] concentration, is inversely associated with RA disease activity. However, it is unclear whether vitamin D deficiency increases the risk of later developing RA. We conducted a systematic review and meta-analysis of pre-diagnostic 25(OH)D concentrations and risk of RA.

METHODS

Medline and Embase databases were searched in December 2021 using various keywords for 'vitamin D', 'rheumatoid arthritis', and 'prospective study'. Publications identified from the search were screened for eligibility, studies were excluded if vitamin D status was measured at or after RA diagnosis, and data were extracted from relevant articles. Bayesian meta-analysis was used to estimate the summary relative risk (RR) and 95% credible interval (CrI) for risk of RA in relation to circulating 25(OH)D concentrations, as well as the between-study heterogeneity.

RESULTS

The search strategy yielded 908 records, of which 4 publications reporting on 7 studies, involving a total of 15,604 participants and 1049 incident RA cases, were included in the meta-analysis. There was no suggestion of an association between 25(OH)D concentration and subsequent risk of RA. The pooled RR per 25 nmol/L increment in 25(OH)D was 0.96 (95% CrI 0.82-1.13; I² = 52%). No associations were evident in men (RR = 1.02, 95% CrI 0.65-1.61; I² = 77%, 2 studies) or women (RR = 0.94, 95% CrI 0.73-1.22; I² = 71%, 4 studies).

CONCLUSIONS

This systematic review and meta-analysis did not identify evidence of an association between 25(OH)D and RA risk, but there was notable between-study heterogeneity and a lack of precision. Investigations in large-scale prospective studies with long follow-up or suitably designed Mendelian randomisation studies with consideration of potential non-linear relationships are needed to determine whether vitamin D is involved in RA aetiology.

Risk Factors for Developing Rheumatoid Arthritis in Patients With Undifferentiated Arthritis and Inflammatory Arthralgia

Currently, there is an increasing interest in treating patients at risk of rheumatoid arthritis (RA) to prevent the development of this chronic disease. In this sense, research has focused attention on the early identification of predictive factors of this disease. Autoantibodies and markers of systemic inflammation can be present before clinical arthritis and RA development. So, the phase of inflammatory arthralgia preceding clinical arthritis is an important part of the window of opportunity and, starting treatment might prevent progression to chronic arthritis. Additionally, the early diagnosis and treatment initiation, in patients with inflammatory arthritis at risk of persistence and/or erosive progression, are fundamental because may allow optimal clinical responses, better chances of achieving sustained remission, preventing irreversible organ damage and optimizing long-term outcomes. This review aims to give an overview of clinical risk factors for developing RA, both in suspected arthralgia and in undifferentiated arthritis. Besides taking into consideration the role of serological markers (immunological and acute phase reactants) and clinical features assessed at consultation such as: articular affection and patient's clinical perception. Other features as sociodemographic and environmental factors (lifestyle habits, microbiota, periodontal disease among others), have been included in this revision to give an insight on strategies to prevent development of RA and/or to treat it in early stages.

Vitamin D and early rheumatoid arthritis

BACKGROUND

Previous studies have linked rheumatoid arthritis (RA) risk and disease activity with vitamin D-deficiency (low serum 25-hydroxyvitamin D (25OHD)), but a causal role for vitamin D in RA is still unclear, with conflicting results from many previous studies, partly due to heterogeneity in study design and patient populations. In this study we aimed to (1) analyse serum 25OHD in early inflammatory arthritis, (2) compare 25OHD with disease activity and fatigue in early RA and (3) determine whether low 25OHD is associated with progression to RA.

METHODS

An analysis of 790 patients recruited to the Birmingham Early Inflammatory Arthritis Cohort and followed longitudinally to determine clinical outcomes. The following were recorded at baseline: demographic data, duration of symptoms, duration of early morning stiffness (EMS), tender and swollen joint counts, Visual Analogue Scale (VAS) pain/fatigue/EMS, PHQ-9, HAQ and FACIT-Fatigue scores, DAS28-ESR, DAS28-CRP, CRP, ESR, anti-CCP antibody status, rheumatoid factor status, and serum 25OHD (ng/ml). Diagnosis was recorded at 0 and 12 months onwards as either RA, Undifferentiated Inflammatory Arthritis (UIA; synovitis not meeting other classification/diagnostic criteria), Clinically Suspect Arthralgia (CSA; arthralgia of an inflammatory type without synovitis), or Other.

RESULTS

Baseline demographic data were similar between all groups, with median symptom duration of 16.8-34.0 days. Baseline 25OHD was not significantly different between groups [median, interquartile range (IQR): RA 46.7, 30.0-73.3; UIA 51.4, 30.0-72.3; CSA 47.7, 30.3-73.0; Other 39.9, 28.6-62.2]. In RA (n = 335), there were no significant differences between 25OHD and measures of disease activity or fatigue. No association between 25OHD and progression from UIA or CSA to RA was observed.

CONCLUSIONS

There was no clear association between serum 25OHD and baseline diagnosis, RA disease activity, or progression from UIA or CSA to RA. Future studies of other vitamin D metabolites may better define the complex role of vitamin D in RA.

Dietary Habits and Nutrition in Rheumatoid Arthritis: Can Diet Influence Disease Development and Clinical Manifestations?

Rheumatoid arthritis (RA) is a systemic, autoimmune disease characterized by joint involvement, with progressive cartilage and bone destruction. Genetic and environmental factors determine RA susceptibility. In recent years, an increasing number of studies suggested that diet has a central role in disease risk and progression. Several nutrients, such as polyunsaturated fatty acids, present anti-inflammatory and antioxidant properties, featuring a protective role for RA development, while others such as red meat and salt have a harmful effect. Gut microbiota alteration and body composition modifications are indirect mechanisms of how diet influences RA onset and progression. Possible protective effects of some dietary patterns and supplements, such as the Mediterranean Diet (MD), vitamin D and probiotics, could be a possible future adjunctive therapy to standard RA treatment. Therefore, a healthy lifestyle and nutrition have to be encouraged in patients with RA.

Vitamin D Deficiency and Rheumatoid Arthritis: Epidemiological, Immunological, Clinical and Therapeutic Aspects

Background/Aim:

Vitamin D displays an immunologic effect which can modulate function of Th17-related cytokines and thereby prevent perpetuation of inflammation in chronic disorders like rheumatoid arthritis (RA). This review aims to conduct a literature review to provide a summary of recent studies addressing the relationship between vitamin D deficiency and RA based on epidemiological, immunological and therapeutic aspects.

Methods:

PubMed, Scopus and Google scholar were searched for relevant papers published between 2000–2018.

Results:

Low intake of vitamin D increases the risk of incident RA, and vitamin D deficiency has been shown to be inversely associated with RA activity in most of these studies. However, characteristics of RA and serum vitamin D status differ across the studies. The results of studies on the effect of supplemental vitamin D in RA vary, from no efficacy to significant improvement in disease activity, as well as quality of life. This should be attributed to variations in dosage of vitamin D, duration of treatment, baseline serum vitamin D in RA patients and characteristics of RA across diverse studies.

Conclusion:

Current data indicate a therapeutic potential for vitamin D in RA. However, further studies are needed to identify an optimal and effective dosage, duration of treatment and patients who will get the best benefit from the treatment.

Vitamin D, Inflammation and Osteoporosis in Rheumatoid Arthritis

Patients with Rheumatoid Arthritis (RA) commonly develop osteoporosis and fragility fractures. This fact cannot be explained only with the use of glucocorticoids, known to be detrimental for bone health. RA is characterized by a chronic inflammation caused by the continuous activation of innate and adaptive immunity with proinflammatory cytokines overproduction. This process is detrimental for several organs and physiological processes, including the impairment of bone remodeling. We will briefly review the pathogenesis of inflammation-related bone loss in RA, describing well-known and new molecular pathways and focusing on vitamin D and Parathyroid Hormone role.

Vitamin D in individuals before onset of rheumatoid arthritis - relation to vitamin D binding protein and its associated genetic variants

Background

Vitamin D has been implicated as being involved in the aetio-pathogenesis of several autoimmune diseases including rheumatoid arthritis (RA). Previous studies present contradictory results. Vitamin D binding protein (DBP), the major transport protein, is also involved in various inflammatory processes. The aim of this study was to investigate the relationship between circulating levels of 25-hydroxyvitamin D [25(OH) D], DBP and polymorphisms in group-specific component (GC) in pre-symptomatic individuals and matched controls within prospective cohorts of the Northern Sweden.

Methods

Blood samples donated to the Medical Biobank prior to the onset of symptoms of RA (n = 515, mean [SD] time before the onset of symptoms 6.2 [9.3] years) and from matched (2:1) population-based controls (n = 267) were used. Plasma 25(OH) vitamin D levels were analyzed using liquid chromatography tandem-mass spectrometry and DBP levels were analyzed using enzyme-linked immunosorbent assay. GC polymorphisms (rs4588 and rs7041) were analyzed with TaqMan assays (Applied Biosystems).

Results

Levels of 25(OH) D or DBP were not statistically different between pre-symptomatic individuals and controls in a crude, or a multiple-adjusted logistic regression model. However, an increased risk for future RA was found in females of DBP (OR 1.014 [95%CI 1.001-1.028]) per 10 mg/L adjusted for carriage of the minor allele of rs4588, in a multiple-adjusted model (p < 0.05).

Conclusions

This study indicated that vitamin D is not associated with the future risk of RA although increasing levels of DBP were however, associated with an increased risk of disease in females carrying the minor allele of a DBP encoding SNP.

Risk factor assessment of rheumatoid arthritis in North Kerala

OBJECTIVE

Rheumatoid arthritis (RA) is a multifactorial disease; it leads to disabling and painful chronic inflammatory arthritis. Its onset may be delayed or even prevented by modifying the risk factors involved. Many genetic, epigenetic, and environmental factors are implicated in the pathogenesis of RA. The objectives of this case-control study were to assess various risk factors in our population and to compare the same with age- and sex-matched controls.

METHODS

We studied 118 cases with RA diagnosed using the EULAR criteria. In total, 581 age- and sex-matched controls were selected. Each individual was administered a separate questionnaire regarding their risk factors (known risk factors were studied). The implicated dietary factors were incorporated in a food frequency questionnaire (FFQ) and administered to both cases and controls. Comparison was made between those who consume an item at a particular frequency, who consume less, and who consume nothing at all. Among those who consume, each group was re-compared. Statistical analysis was conducted using Statistical Package for Social Sciences (IBM Corp.; Armonk, NY, USA).

RESULTS

There was significant relationship for family history, periodontitis, history of chikungunya, and sun exposure (p<0.05). Association with various food items was studied using the FFQ, but the relationship was inconsistent, probably due to consumption of modified diet by the persons with RA. Also, a majority of cases were females and nonsmokers for assessing an association with smoking habits.

CONCLUSION

In our population, previous infections (e.g., chikungunya and poor oral hygiene with periodontitis) were the prominently observed risk factors. Also, smoking was less common among women, and probably contributed less, as majority of cases were females. For dietary pattern association, a prospective cohort study may be needed.

Vitamin D deficiency as a risk factor for the development of autoantibodies in patients with ASIA and silicone breast implants: a cohort study and review of the literature

The development of autoimmunity and/or autoimmune diseases is multifactorial. Vitamin D is one of the factors that might play a role. We postulated that both the presence of adjuvants and insufficient levels of vitamin D may result in the development of autoimmunity in patients with autoimmune/inflammatory syndrome induced by adjuvants (ASIA) in relation to silicone implant incompatibility. We measured vitamin D levels in 135 patients with ASIA in relation to silicone implant incompatibility and related findings to the presence of autoantibodies that are commonly used to diagnose systemic autoimmune diseases. Furthermore, we systematically reviewed the literature regarding vitamin D deficiency as a risk factor for the development of autoantibodies. Vitamin D measurements were available for analysis in 131 of 135 patients with ASIA in relation to SIIS. Twenty-three patients (18%) tested positive for autoantibodies, from which 18 patients (78%) had either a vitamin D deficiency or insufficiency (median vitamin D level 60.5 mmol/L), whereas five patients (22%) had sufficient vitamin D levels. The risk to develop autoantibodies was significantly increased in vitamin D deficient and/or insufficient patients [RR 3.14; 95% CI, 1.24–7.95; p = 0.009]. Reviewed literature suggested an association between vitamin D levels and the presence and/or titer levels of autoantibodies in different autoimmune diseases. From our current study and from our review of the literature, we conclude that vitamin D deficiency is related to the presence of autoantibodies. Whether vitamin D supplementation results in a decrease of autoimmunity needs to be studied prospectively.

Role of Vitamin D in Rheumatoid Arthritis

Vitamin D is a fat soluble hormone, with a well described role in bone health and calcium/phosphate metabolism. Recent evidences have related vitamin D to other physiological functions and pathological conditions. Specifically, vitamin D has widely proven activities on immune system and evidences suggest that it may be implicated in the pathogenesis of rheumatoid arthritis (RA). The relationship between vitamin D and RA is complex, also because a deficitary vitamin D status, which is very common in RA patients, can contribute to the increased risk of osteoporosis typical of RA. In this chapter, will be described and discussed the main aspects of the relationship between RA and vitamin D.

Vitamin D in rheumatoid arthritis-towards clinical application

In addition to its well-documented involvement in mineral homeostasis, vitamin D seems to have broad effects on human health that go beyond the skeletal system. Prominent among these so-called nonclassical effects of vitamin D are its immunomodulatory properties. In vitro studies have shown anti-inflammatory effects of 1,25-dihydroxyvitamin D (1,25(OH)2D), the active form of vitamin D. In addition, epidemiological analysis of patients with established inflammatory disease identified associations between vitamin D deficiency (low serum concentrations of inactive 25-hydroxyvitamin D, abbreviated to 25(OH)D) and inflammatory conditions, including rheumatoid arthritis (RA). The association of vitamin D deficiency with RA severity supports the hypothesis of a role for vitamin D in the initiation or progression of the disease, or possibly both. However, whether 25(OH)D status is a cause or consequence of RA is still incompletely understood and requires further analysis in prospective vitamin D supplementation trials. The characterization of factors that promote the transition from preclinical to clinical phases of RA has become a major focus of research, with the aim to facilitate earlier diagnosis and treatment, and improve therapeutic outcomes. In this Review, we aim to describe the current knowledge of vitamin D and the immune system specifically in RA, and discuss the potential benefits that vitamin D might have on slowing RA progression.

Towards prevention of autoantibody-positive rheumatoid arthritis: from lifestyle modification to preventive treatment

Recent advances in research into the earliest phases of RA have provided additional insights into the processes leading from the healthy to the diseased state. These insights have opened the way for the development of preventive strategies for RA, which represents a significant paradigm shift from treatment to prevention and will have major implications for patients as well as society. It would be a huge step forward if clinical signs and symptoms, disability, impaired quality of life and the need for chronic immunosuppressive treatment could be prevented. RA can be seen as a prototypic autoimmune disease, and discoveries about the preclinical diseased state for RA could potentially facilitate research into prevention of other immune-mediated inflammatory diseases such as type 1 diabetes, SLE and multiple sclerosis. This review focuses on the current knowledge of factors contributing to the development of RA and discusses the opportunities for intervention.

Role of vitamin D in flare ups of rheumatoid arthritis

INTRODUCTION

Rheumatoid arthritis (RA) is one of the most prevalent autoimmune diseases worldwide. Some researchers have suggested that the serum vitamin D (Vit D) level may relate to disease activity. The current study was designed to identify the correlation between vitamin D prescription and prevention of relapses in rheumatoid arthritis.

PATIENTS AND METHOD

A double blinded, randomized controlled trial study was performed using 80 RA patients. RA was controlled and patients were in remission during the past 2 months. Serum level of Vit D in the studied patients was below 30 ng/dl. Patients were randomly allocated to receive Vit D or placebo. In the 6-month follow-up period, the Disease Activity Score 28 (DAS28) was used in case of relapses as an index of RA activity to compare the two groups.

RESULTS

The flare rate was not different between two groups (p > 0.05). The odds ratio of the rate of decline in patients of the trial group compared with the control group was 1.17 (not significant; p > 0.05). The mean DAS28 between the two patient groups was not significant (p > 0.05).

CONCLUSION

A low Vit D level was not identified to be a risk factor for RA severity or flare ups; however, although not statistically significant, Vit D treatment might be clinically effective. Further studies are needed with more emphasis on the issue of cost effectiveness and clinical importance to provide more information.

Prediction of future rheumatoid arthritis

Rheumatoid arthritis (RA) results from an interaction between genetic susceptibility and environmental factors. Several of these factors are known, such as family history of RA, high birth weight, smoking, silica exposure, alcohol nonuse, obesity, diabetes mellitus, rheumatoid factor, anti-citrullinated protein antibody, and genetic variants such as the shared epitope and protein tyrosine phosphatase nonreceptor type 22. The impact of these factors can be modeled in the 2 main groups at risk of RA: family members of patients with RA and seropositive persons with or without arthralgia. Current models have the potential to select individuals for preventive strategies.

Lifestyle modifications to improve musculoskeletal and bone health and reduce disability--a life-course approach

This review covers the evidence relating to lifestye modification in the big three musculoskeletal conditions: osteoarthritis, osteoporosis and rheumatoid arthritis. Lifestyle is of considerable importance in the first two and there is emerging evidence for rheumatoid arthritis despite it not traditionally being considered a lifestyle disease.

Determinants of vitamin D levels in children, adolescents, and young adults with juvenile idiopathic arthritis

OBJECTIVE

Deficiency of 25-hydroxyvitamin D [25(OH)D] is reported to be common in patients with rheumatoid arthritis (RA); data in patients with juvenile idiopathic arthritis (JIA) are inconsistent. We assessed serum 25(OH)D in children, adolescents and young adults with JIA, in order to identify the risk factors for vitamin D deficiency in patients with JIA.

METHODS

We evaluated 152 patients with JIA: 115 female, 37 male, mean age 16.2 ± 7.4 yrs; evaluated by onset type, 96 had oligoarticular, 35 polyarticular, 7 systemic, and 14 enthesitis-related arthritis (ERA). Patients were compared with a control group matched for sex and age. All patients and controls underwent laboratory tests of plasma 25(OH)D, parathyroid hormone (PTH), calcium, phosphorus, and bone alkaline phosphatase levels, and dual-energy x-ray absorptiometry examination.

RESULTS

Patients with JIA showed significantly reduced 25(OH)D levels compared to controls (p < 0.001), even divided into subtypes (oligoarticular, p < 0.05; polyarticular, p < 0.005; systemic, p < 0.001; ERA, p < 0.005). Patients with active disease and/or frequent relapses had significantly reduced 25(OH)D levels compared to patients with no active disease and no frequent flares (p < 0.005, respectively). Nevertheless, JIA patients had significantly higher PTH levels compared to controls (p < 0.0001). JIA patients with 25(OH)D deficiency showed a significantly lower bone mineral apparent density than those with normal 25(OH)D levels (p < 0.001).

CONCLUSION

JIA patients have reduced 25(OH)D and higher PTH values. This may explain at least in part why JIA patients, despite more effective current drugs, do not achieve bone-normal condition over time. JIA patients with more severe disease could require higher supplementation of vitamin D to maintain normal 25(OH)D serum levels. Longterm studies are needed to investigate the relationship between serum 25(OH)D levels and disease activity in JIA.

Circulating 25-hydroxyvitamin D level and risk of developing rheumatoid arthritis

OBJECTIVE

The aim of this study was to examine the relationship between preclinical circulating 25-hydroxyvitamin D [25(OH)D] and RA in two nested case-control studies within the prospective cohort Nurses' Health Study (NHS) and NHS II (NHSII).

METHODS

We included 166 women with RA and blood specimens collected 3 months to 16 years prior to the first RA symptom and 490 matched controls (3:1, matched on age, date of blood draw, hormonal factors). We calculated the odds ratio (OR) and 95% CI for incident RA using conditional logistic regression multivariable adjusted models, including additional covariates for smoking status, parity and breastfeeding, alcohol consumption, BMI, median income and region of residence in the USA. We repeated analyses stratified by time from blood draw to RA diagnosis (3 months to <4 years or ≥4 years) and meta-analysed estimates from the two cohorts using fixed effects models.

RESULTS

Incident RA was confirmed in 120 NHS [mean age 63.8 years (s.d. 8.2)] and 46 NHSII participants [mean age 48.5 years (s.d. 4.7)]. Mean time from blood draw to RA diagnosis was 7.8 years (s.d. 4.2) for NHS and 4.2 years (s.d. 2.0) for NHSII participants. Meta-analysis of crude and multivariable-adjusted conditional logistic models did not show significant associations between circulating 25(OH)D and RA. However, among NHSII women with blood drawn between 3 months and <4 years prior to RA diagnosis, there was a 20% decreased risk of RA associated with each 1 ng/ml increase in 25(OH)D [OR 0.80 (95% CI 0.64, 0.99)].

CONCLUSION

We did not observe a significant association between circulating 25(OH)D levels and RA, except for among a small subset of NHSII women with levels measured closest to RA diagnosis.

Low vitamin D level is not associated with increased incidence of rheumatoid arthritis

To evaluate the association of vitamin D level with incident rheumatoid arthritis (RA) in a patient population using electronic health records (EHR). Case-control study with data extracted from EHR from 1/1/2001 to 12/31/2012 in the Geisinger Health System (GHS). Incident RA was defined as International Classification of Disease-9 code 714.0 twice by a GHS rheumatologist. Patients were identified at time of RA diagnoses and were matched 1:5 for age and gender with non-RA controls. Vitamin D levels were identified and extracted prior to RA diagnosis. The subjects were followed retrospectively with regard to their vitamin D levels; the most recent value of vitamin D prior to the RA diagnosis was used in the analysis. Vitamin D levels were treated both as continuous and categorical with two different cutoff values, 30 and 20 ng/ml. The association between vitamin D and RA was presented as the odds ratios with 95 % confidence intervals (OR, 95 % CI) from a conditional logistic regression model adjusting for obesity and smoking status. A total of 270 patients with incident RA and 1,341 matched controls were identified. The RA patients were 83.3 % female with median age at RA diagnosis of 62 years. The adjusted OR (95 % CI) for the association of vitamin D levels with incident RA compared with controls was 1.00 (0.99, 1.01), 0.98 (0.75, 1.29) and 1.12 (0.80, 1.57) for continuous, <30 and <20 ng/ml vitamin D levels, respectively. Subgroup analysis according to gender or rheumatoid factor positivity yielded similar results. In this patient population, vitamin D levels were not associated with the development of RA.

Vitamin D: Update 2013: From rickets prophylaxis to general preventive healthcare

Vitamin D has received a lot of attention recently as a result of a meteoric rise in the number of publications showing that vitamin D plays a crucial role in a plethora of physiological functions and associating vitamin D deficiency with many acute and chronic illnesses including disorders of calcium metabolism, autoimmune diseases, some cancers, type 2 diabetes mellitus, infectious diseases and cardiovascular disease. The recent data on vitamin D from experimental, ecological, case-control, retrospective and prospective observational studies, as well as smaller intervention studies, are significant and confirm the sunshine vitamin's essential role in a variety of physiological and preventative functions. The results of these studies justify the recommendation to improve the general vitamin D status in children and adults by means of a healthy approach to sunlight exposure, consumption of foods containing vitamin D and supplementation with vitamin D preparations. In general, closer attention should therefore be paid to vitamin D deficiency in medical and pharmaceutical practice than has been the case hitherto.

Exposure to ultraviolet-B and risk of developing rheumatoid arthritis among women in the Nurses' Health Study

OBJECTIVE

To examine the association between ultraviolet-B (UV-B) light exposure and rheumatoid arthritis (RA) risk among women in two large prospective cohort studies, the Nurses' Health Study (NHS) and the Nurses' Health Study II (NHSII).

METHODS

A total of 106 368 women from NHS, aged 30-55 years in 1976, and 115 561 women from NHSII, aged 25-42 in 1989, were included in the analysis. We identified women with incident RA from the start of each cohort until 2008 (NHS) and 2009 (NHSII). Cumulative average UV-B flux, a composite measure of ambient UV exposure based on latitude, altitude and cloud cover, was estimated according to state of residence and categorised as low, medium or high. Estimates of UV-B at birth and age 15 years were also examined. We used multivariable-adjusted Cox proportional hazards models to estimate HR and 95% CI.

RESULTS

1314 incident RA cases were identified in total. Among NHS participants, higher cumulative average UV-B exposure was associated with decreased RA risk; those in the highest versus lowest category had a 21% decreased RA risk (HR (95% CI); 0.79 (0.66 to 0.94)). UV-B was not associated with RA risk among younger women in NHSII (1.12 (0.87 to 1.44)). Results were similar for UV-B at birth and at age 15.

CONCLUSIONS

These results suggest that ambient UV-B exposure is associated with a lower RA risk in NHS, but not NHSII. Differences in sun-protective behaviours (eg, greater use of sun block in younger generations) may explain the disparate results.

The effect of vitamin D levels on the assessment of disease activity in rheumatoid arthritis

Disease activity in rheumatoid arthritis (RA) is assessed by a combination of objective and subjective tests, combined to produce a disease activity score in 28 joints (DAS28). There is some evidence that RA disease activity, as assessed by DAS28, can be influenced by vitamin D levels. It is difficult to know whether this is due to a true immunomodulatory effect of vitamin D or a more subjective effect of low vitamin D on pain perception. We addressed this issue by comparing vitamin D levels with disease activity, analysing each component of the DAS28 score separately. We measured 25-hydroxy vitamin D levels in 176 outpatients with RA at two different centres and recorded a DAS28 score using an ESR checked at the same time. We calculated DAS28 both with and without the patient's rating of their symptoms on the visual analogue score (VAS) to assess the effect of VAS on DAS28. The vitamin D results were expressed as nanomole per litre with 50 nmol/l taken as the lower limit of normal. We calculated mean levels of vitamin D and undertook a multivariate regression analysis to assess correlations between vitamin D levels and DAS28 (and its individual components), corrected for centre, age and gender. The overall mean DAS28 score was 3.66 (SE ± 0.11) using all four criteria and 3.43 (SE ± 0.10) using just three criteria (omitting VAS). The mean vitamin D level was 39.42 nmol/l (SE ± 1.55). There was no significant correlation between vitamin D and DAS28 scores with or without the inclusion of VAS. However, there was a significant inverse relationship between vitamin D and VAS itself (coefficient = 0.249, p = 0.013). The mean DAS28 score was greater in vitamin D-deficient patients and this was explained by their higher VAS scores. Our data confirms that vitamin D deficiency is common in RA. This paper provides evidence that the VAS component, assessing patient perception of symptoms, is inversely related to vitamin D, with lower levels producing higher VAS values. Although there was no overall correlation between vitamin D levels and DAS28, patients may perceive themselves or be perceived by assessors as having responded less well to disease modification in the presence of vitamin D deficiency. This could have major implications for subsequent management, and clinicians need to be aware of the potential confounding effect of vitamin D deficiency in assessing RA disease activity using the full DAS28 tool.

Sunlight and Vitamin D: A global perspective for health

Vitamin D is the sunshine vitamin that has been produced on this earth for more than 500 million years. During exposure to sunlight 7-dehydrocholesterol in the skin absorbs UV B radiation and is converted to previtamin D3 which in turn isomerizes into vitamin D3. Previtamin D3 and vitamin D3 also absorb UV B radiation and are converted into a variety of photoproducts some of which have unique biologic properties. Sun induced vitamin D synthesis is greatly influenced by season, time of day, latitude, altitude, air pollution, skin pigmentation, sunscreen use, passing through glass and plastic, and aging. Vitamin D is metabolized sequentially in the liver and kidneys into 25-hydroxyvitamin D which is a major circulating form and 1,25-dihydroxyvitamin D which is the biologically active form respectively. 1,25-dihydroxyvitamin D plays an important role in regulating calcium and phosphate metabolism for maintenance of metabolic functions and for skeletal health. Most cells and organs in the body have a vitamin D receptor and many cells and organs are able to produce 1,25-dihydroxyvitamin D. As a result 1,25-dihydroxyvitamin D influences a large number of biologic pathways which may help explain association studies relating vitamin D deficiency and living at higher latitudes with increased risk for many chronic diseases including autoimmune diseases, some cancers, cardiovascular disease, infectious disease, schizophrenia and type 2 diabetes. A three-part strategy of increasing food fortification programs with vitamin D, sensible sun exposure recommendations and encouraging ingestion of a vitamin D supplement when needed should be implemented to prevent global vitamin D deficiency and its negative health consequences.

Can supplementation with vitamin D reduce the risk or modify the course of autoimmune diseases? A systematic review of the literature

OBJECTIVE

To evaluate whether vitamin D levels are related to the risk of developing autoimmune diseases and whether supplementation with vitamin D can modify the course of the diseases.

METHODS

We reviewed the most relevant papers published from January 1973 to October 2011, using Medline and EMBASE and the search terms "vitamin D"; "autoimmune disease"; "autoimmunity"; "rheumatoid arthritis"; "systemic lupus erythematosus"; "scleroderma"; "systemic sclerosis"; "type 1 diabetes"; "multiple sclerosis"; and "undifferentiated connective tissue disease". We selected studies on the environmental, genetic and epidemiologic association of vitamin D with autoimmune diseases. Using the strategy described, we identified 1268 articles. 331 articles were eliminated on the basis of the title and another 703 on the basis of the abstract, since they were considered irrelevant for the purposes of the study. Full-text examination was performed on the remaining 234 studies, and a further 15 studies were excluded from the review, since the results had been confirmed or superseded by more recent research. Finally, a systematic review was conducted on 219 articles concerning cross-sectional data on: vitamin D levels and autoimmune diseases; interventional data on vitamin D supplementation in autoimmune diseases; prospective data linking vitamin D level or intake to autoimmune disease risk.

RESULTS

Physiopathology studies confirm that hypovitaminosis D, in genetically predisposed subjects, can impair self tolerance by compromising the regulation of dendritic cells, of regulatory T-lymphocytes and of Th1 cells. Cross-sectional studies show that levels of vitamin D <30 ng/mL are present in a significant percentage, not only in patients with autoimmune disease, but also in healthy subjects (30-77%), and link profound deficiency (<10 ng/mL) with aggravation of symptomatology, while genetic studies associate polymorphism of vitamin D receptors to various autoimmune diseases. Among experimental studies on humans, only those on type-1 diabetes prove that the risks are significantly reduced in infants treated with vitamin D after the 7th month (OR 0.71, 95% CI, 0.60 to 0.84) and that a dose-response effect exists.

CONCLUSIONS

Basic, genetic, and epidemiological studies indicate a potential role of vitamin D in the prevention of autoimmune diseases, but randomized and controlled trials are necessary to establish the clinical efficacy of vitamin D supplementation in ill or at-risk subjects.

Tobacco and other environmental risk factors in rheumatoid arthritis

Many environmental factors have been associated with an increased risk of developing Rheumatoid Arthritis (RA), but so far smoking is the only environmental risk factor that has been extensively studied and widely accepted. Smoking is associated with an increased risk of developing seropositive RA (RF and/or ACPA). Recent studies show that tobacco smoking can influence disease phenotype, with the development of more aggressive disease and greater joint damage; but other studies show contradictory results. Recent data suggests that response to antirheumatic therapy in RA is worse in smokers. In this article we review different environmental factors that have been associated with an increased risk of developing RA, with a special interest in tobacco smoking.

Effects of rituximab treatment on the serum concentrations of vitamin D and interleukins 2, 6, 7, and 10 in patients with rheumatoid arthritis

Background

Rituximab, a monoclonal antibody that selectively targets CD20-positive B-lymphocytes, is used for the treatment of patients with rheumatoid arthritis (RA) with an inadequate response or tolerance to tumor necrosis factor inhibitors. The objective of this study was to investigate the effects of rituximab treatment on the serum concentrations of vitamin D, interleukin (IL) 2, IL-6, IL-7, and IL-10 in patients with rheumatoid arthritis (RA).

Methods

Forty-five patients, aged 25–78 years, were enrolled into a cohort prospective study. All patients were treated with intravenous rituximab. Disease activity score-28 (DAS-28) and serum concentrations of rheumatoid factor (RF), C-reactive protein (CRP), anticyclic citrullinated peptide (anti-CCP), erythrocyte sedimentation rate (ESR), health assessment questionnaire (HAQ), vitamin D, ILs 2, 6, 7, and 10 were estimated in the patients before and after treatment with rituximab.

Results

DAS-28, HAQ score, and serum concentrations of CRP, RF, anti-CCP, IL-2, IL-6, IL-7, IL-10, and ESR significantly decreased after treatment. All 45 patients had vitamin D deficiency before treatment and this did not significantly change after treatment. However no significant association was found among serum vitamin D concentration and any of the ILs.

Conclusion

We concluded from this study that although rituximab treatment of patients with RA significantly reduced their disease activity and serum concentrations of IL-2, IL-6, IL-7, and IL-10, it did not significantly alter their vitamin D status. Furthermore, no significant association was found among serum vitamin D concentration and any of the ILs.

Modifiable risk factors for RA: prevention, better than cure?

Objective. To perform a meta-synthesis of the evidence for modifiable lifestyle risk factors for inflammatory polyarthritis (IP) and RA.

Methods. We performed a MEDLINE literature search. Case–control and cohort studies and systematic reviews published from 1948 through February 2011 and studying modifiable risk factors for RA were retrieved. The main outcome measure was diagnosis of RA according to the standard criteria.

Results. Smoking contributes up to 25% of the population burden of RA. The risk is dose related, stronger in males and especially strong for anti-citrullinated peptide antibody positive (ACPA⁺) RA through an interaction with the shared epitope. After smoking cessation, there is, however, a latency of up to 20 years to return to baseline risk. Other associations are less definitive; however, prospective studies suggest that dietary antioxidants and breastfeeding may be protective and that high coffee consumption may increase RA risk. An inverse association with alcohol intake (especially in smokers) and with education/social class (especially seropositive RA) and an increased risk with obesity (seronegative RA) is also noted.

Conclusion. There is a need for further large-scale prospective studies with a consistent definition of RA phenotype (undifferentiated IP through to ACPA⁺/RF⁺ disease). This will ultimately afford the opportunity to evaluate preventative population strategies for RA akin to the well-established programmes for cardiovascular disease and cancer, targeting common risk factors.

Vitamin D deficiency and connective tissue disease

Recently, the evidence linking vitamin D status as a potential environmental factor affecting autoimmune disease prevalence continues to accumulate. Beyond that the traditional known metabolic activities, vitamin D has been shown to modulate the immune system and has anti-inflammatory properties. The immune-regulatory role of vitamin D affects both the innate and adaptive immune responses contributing to the immune-tolerance of self-structures. Vitamin D deficiency skews the immunologic response towards loss of tolerance. Serum levels of vitamin D have been found to be significantly lower in several autoimmune or immune-mediated diseases than in the healthy population. Experimental animal models and clinical studies show that 1,25-dihydroxyvitamin D3 or vitamin D receptor (VDR) agonists can either prevent or suppress symptoms of type 1 diabetes, experimental autoimmune encephalomyelitis, rheumatoid arthritis, systemic lupus erthyematosus and inflammatory bowel disease. The heading aims at reviewing the complex immune-regulatory role of vitamin D from the cellular and humoral level through animal models of autoimmune rheumatic diseases and representing the known contribution of vitamin D in the pathogenesis of connective tissue diseases. Increased vitamin D intakes might reduce the incidence and severity of autoimmune disorders besides reducing the rate of osteoporotic bone fracture.

Vitamin D endocrine system and the immune response in rheumatic diseases

Epidemiological evidence indicates a significant association between vitamin D deficiency and an increased incidence of autoimmune diseases. The presence of vitamin D receptors (VDRs) in the cells of the immune system and the fact that several of these cells produce the vitamin D hormone suggested that vitamin D could have immunoregulatory properties, and now potent immunomodulatory activities on dendritic cells, Th1 and Th17 cells, as well as B cells have been confirmed. Serum levels of vitamin D have been found to be significantly lower in patients with systemic lupus erythematosus, undifferentiated connective tissue disease, and type-1 diabetes mellitus than in the healthy population. In addition, it was also found that lower levels of vitamin D were associated with higher disease activity in rheumatoid arthritis. Promising clinical results together with evidence for the regulation of multiple immunomodulatory mechanisms by VDR agonists represent a sound basis for further exploration of their potential in the treatment of rheumatic autoimmune disorders.

Extraskeletal effects of vitamin D: facts, uncertainties, and controversies

Vitamin D was long viewed as a hormone acting chiefly to regulate calcium-phosphate metabolism and bone mineralization. Over the last decade, however, basic science and clinical researchers have produced a bewildering amount of information on the extraskeletal effects of vitamin D. This article is a review of the clinical and biological actions of vitamin D including effects on the immune system, auto-immune diseases, infections, cancer, metabolic syndrome, fall risk, cognitive function, and muscle function.

Vitamin D and inflammation

Calcitriol, or 1,25-dihydroxyvitamin D3 (1,25(OH)(2)D3) is a well-known endocrine regulator of calcium homeostasis. More recently, local calcitriol production by immune cells was shown to exert autocrine or paracrine immunomodulating effects. Immune cells that produce calcitriol also express the vitamin D receptor (VDR) and the enzymes needed to metabolize vitamin D3 (1α-, 25-, and 24-hydroxylases). Studies of animal models and cell cultures showed both direct and indirect immunomodulating effects involving the T cells, B cells, and antigen-presenting cells (dendritic cells and macrophages) and affecting both innate and adaptive immune responses. The overall effect is a switch from the Th1/Th17 response to the Th2/Treg profile. The immunomodulating effects of vitamin D may explain the reported epidemiological associations between vitamin D status and a large number of autoimmune and inflammatory diseases. Such associations have been suggested by observational studies not only in rheumatoid arthritis, lupus, inflammatory bowel disease, and type 1 diabetes; but also in infections, malignancies, transplant rejection, and cardiovascular disease. In animal models for these diseases, vitamin D supplementation has been found to produce therapeutic effects. Thus, vitamin D is a key focus for public health efforts and may hold promise for the treatment of dysimmune diseases.

Does vitamin D affect risk of developing autoimmune disease?: a systematic review

OBJECTIVES

We evaluated the epidemiologic evidence that vitamin D may be related to human autoimmune disease risk.

METHODS

PubMed, limited to English from inception through April 2010, was searched using keywords: "vitamin D," "autoimmune," and autoimmune disease names. We summarized in vitro, animal, and genetic association studies of vitamin D in autoimmune disease pathogenesis. We sorted epidemiologic studies by design and disease and performed a systematic review of (a) cross-sectional data concerning vitamin D level and autoimmune disease; (b) interventional data on vitamin D supplementation in autoimmune diseases; and (c) prospective data linking vitamin D level or intake to autoimmune disease risk.

RESULTS

Vitamin D has effects on innate and acquired immune systems, and vitamin D receptor polymorphisms have been associated with various autoimmune diseases. In experimental animal models, vitamin D supplementation can prevent or forestall autoimmune disease. Of 1446 studies identified and screened, 76 studies examined vitamin D levels in autoimmune disease patients, particularly with active disease, and compared with controls. Nineteen observational or interventional studies assessed the effect of vitamin D supplementation as therapy for various autoimmune diseases (excluding psoriasis and vitiligo) with a range of study approaches and results. The few prospective human studies performed conflict as to whether vitamin D level or intake is associated with autoimmune disease risk. No interventional trials have investigated whether vitamin D affects human autoimmune disease risk.

CONCLUSIONS

Cross-sectional data point to a potential role of vitamin D in autoimmune disease prevention, but prospective interventional evidence in humans is still lacking.

Prevalence of vitamin D insufficiency/deficiency in rheumatoid arthritis and associations with disease severity and activity

OBJECTIVE

25-hydroxy-vitamin D (25-OH-D) insufficiency/deficiency is increasingly prevalent and has been associated with many chronic diseases, including rheumatoid arthritis (RA). Our purpose was to define the prevalence and associations of 25-OH-D insufficiency/deficiency in a cohort of US veterans with RA.

METHODS

vitamin D status (25-OH-D) was assessed in patients with RA using radioimmunoassay on banked plasma collected at enrollment. Insufficiency was defined as concentrations < 30 ng/ml and deficiency as < 20 ng/ml. Associations of 25-OH-D insufficiency/deficiency with patient characteristics obtained at enrollment were examined using multivariate logistic regression, adjusting for age, sex, season of enrollment, and race.

RESULTS

patients (850 men, 76% Caucasian) had a mean (SD) age of 64 (SD 11.3) years. The prevalences of 25-OH-D insufficiency and deficiency were 84% and 43%, respectively. After multivariate adjustment, both insufficiency and deficiency were more common with anti-cyclic citrullinated peptide antibody positivity and non-Caucasian race, and in the absence of vitamin D supplementation. 25-OH-D deficiency, but not insufficiency, was independently associated with higher tender joint counts and highly sensitive C-reactive protein levels.

CONCLUSION

in a predominantly elderly, male RA population, 25-OH-D insufficiency was highly prevalent. With the increasing adverse health outcomes associated with hypovitaminosis D, screening and supplementation, particularly among minority, seropositive patients with RA, should be performed routinely.

Vitamin D and molecular actions on the immune system: modulation of innate and autoimmunity

Vitamin D has received increased attention recently for its pleiotropic actions on many chronic diseases. The importance of vitamin D on the regulation of cells of the immune system has gained increased appreciation over the past decade with the discovery of the vitamin D receptor (VDR) and key vitamin D metabolizing enzymes expressed by cells of the immune system. Animal studies, early epidemiologic and clinical studies have supported a potential role for vitamin D in maintaining immune system balance. The hormonal form of vitamin D up-regulates anti-microbial peptides, namely cathelicidin, to enhance clearance of bacteria at various barrier sites and in immune cells. Vitamin D modulates the adaptive immune system by direct effects on T cell activation and on the phenotype and function of antigen-presenting cells (APCs), particularly of DCs. The purpose of this manuscript is to review the molecular and clinical evidence for vitamin D as a modulator of the innate and adaptive immune system.

Vitamin D status and its associations with disease activity and severity in African Americans with recent-onset rheumatoid arthritis

OBJECTIVE

To examine the prevalence of vitamin D insufficiency and the associations of vitamin D concentration with disease status in African Americans with rheumatoid arthritis (RA).

METHODS

Study participants (n = 266) were enrolled in the Consortium for the Longitudinal Evaluation of African Americans with Early RA (CLEAR) Registry. The vitamin 25(OH)-D was measured on baseline plasma, and associations of 25(OH)-D with disease status (baseline and at 3 years' disease duration) were examined using univariate and multivariate regression.

RESULTS

The prevalence of 25(OH)-D insufficiency (<or= 37.5 nmol/l or 15 ng/ml) was 50%, with the highest prevalence in winter. In unadjusted analyses, vitamin D concentrations were inversely associated with baseline pain (p = 0.04), swollen joints (p = 0.04), and Disease Activity Score (DAS28, p = 0.05) but not with measures at 3 years' disease duration. There were no multivariate associations of 25(OH)-D with any disease measures at baseline or at 3 years, with the exception of a positive borderline association with rheumatoid factor positivity at enrollment (p = 0.05).

CONCLUSION

Vitamin D insufficiency is common in African Americans with recent-onset RA. Unadjusted associations of circulating vitamin D with baseline pain, swollen joints, and DAS28 were explained by differences in season, age, and gender and were not significant in multivariate analyses. In contrast to reports of Northern Europeans with early inflammatory arthritis, there are not strong associations of 25(OH)-D concentration with symptoms or disease severity in African Americans with RA.

Environmental influences on risk for rheumatoid arthritis

PURPOSE OF REVIEW

To examine new environmental factors and provide updates on known risk factors for rheumatoid arthritis (RA) in the past 2 years (2006-2008). This review is timely given the expanding information on treatment, pathogenesis and genetic risk factors for RA.

RECENT FINDINGS

High consumption of red meat does not increase risk of RA, whereas alcohol intake may be protective. The role of vitamin D and oral contraceptives as modifiers of disease risk remains equivocal. Other factors associated with increased risk of RA include higher birthweight, living in the northeastern United States compared with other regions of the country, and lower socioeconomic status. Duration of breastfeeding is inversely associated with RA risk. Several studies have now demonstrated that anti-citrullinated protein antibody positive RA has a specific association with environmental risk factors such as smoking.

SUMMARY

Recent studies have increased our understanding of environmental exposures that modify risk for RA such as smoking and alcohol intake. Other factors such as birthweight, breastfeeding, socioeconomic status and region of birth have also been demonstrated to contribute to risk. ACPA status is associated with specific environmental factors and is therefore important to incorporate into present and future studies.