The effect of vitamin D on nonspecific low back pain

Study on Vitamin D Levels in 30 to 40-Year-Old Females With Low Back Pain

BACKGROUND

Vitamin D is associated with many skeletal-related processes in the body. A major health problem concerning decreased quality of life is chronic low back pain (LBP). Many studies have proved that chronic pain improves with Vitamin D supplementation. This study aimed to explore the correlation between vitamin D levels and the occurrence of LBP in women aged 30 to 40.

MATERIALS AND METHODS

A case-control study was taken up at PK Das Institute of Medical Sciences wherein 50 cases (women aged 30-34 years who had chronic LBP >3 months) and 50 age-matched controls were included. Frequencies of Vitamin D deficiency, inadequacy, and sufficiency were studied. The t-test for examining statistical significance was employed to compare means. Keeping a 95% confidence interval (p<0.05), the odds ratio was calculated.

RESULTS

Vitamin D deficiency diagnosed when Vitamin D level is <20ng/mL was found in 74% of cases and 48% of controls. Vitamin D levels were not found to be statistically different between cases and controls. The odds ratio was found to be 3.083 (p=0.009), showing that participants with LBP are more expected to be deficient in Vitamin D compared to those without LBP.

CONCLUSIONS

Although a higher frequency of Vitamin D deficiency was found in cases compared to controls, the mean value of Vitamin D levels was not found to be statistically different amongst cases and controls. A significant Odds ratio establishes a positive association between LBP and Vitamin D deficiency. The reason could be due to most people being restricted indoors due to COVID-19 restrictions. It is essential to standardize the biochemical analysis of Vitamin D and establish appropriate Vitamin D level ranges specifically tailored for the Indian population.

Causal effect of serum 25-hydroxyvitamin D levels on low back pain: A two-sample mendelian randomization study

Background: Previous observational studies have suggested the involvement of 25-hydroxyvitamin D [25(OH)D] in chronic pain. However, whether the 25(OH)D is a novel target for management, the causality remains unclear.

Methods: A two-sample Mendelian randomization (MR) study was conducted to identify the causal association between 25(OH)D and low back pain (LBP). The primary analysis was revealing causality from serum 25(OH)D level (n = 417,580) on LBP (21,140 cases and 227,388 controls). The replicated analysis was performing MR estimates from circulating 25(OH)D concentration (n = 79,366) on LBP experienced last month (118,471 cases and 343,386 controls). Inverse variance weighted (IVW) was used as the main analysis. In addition, we used weighted median and MR-Egger to enhance the robustness. Sensitivity analysis was conducted to evaluate the robustness of MR results.

Results: IVW estimation indicated strong evidence that higher serum 25(OH)D levels exerted a protective effect on LBP (OR = 0.89, 95% CI = 0.83–0.96, p = 0.002). Similar trends were also found in replicate analysis (OR = 0.98, 95% CI = 0.96–1.00, p = 0.07). After meta-analysis combining primary and replicated analysis, the causal effect is significant (p = 0.03). Sensitivity analysis supported that the MR estimates were robust.

Conclusion: In our MR study, genetically increased serum 25(OH)D levels were associated with a reduced risk of LBP in the European population. This might have an implication for clinicians that vitamin D supplements might be effective for patients with LBP in clinical practice.

The Efficacy of Vitamin D Supplementation in the Treatment of Fibromyalgia Syndrome and Chronic Musculoskeletal Pain

Fibromyalgia syndrome (FMS) and chronic widespread musculoskeletal pain (CMP) are diffuse suffering syndromes that interfere with normal activities. Controversy exists over the role of vitamin D in the treatment of these diseases. We carried out a systematic literature review of randomized controlled trials (RCT) to establish whether vitamin D (25OHD) deficiency is more prevalent in CMP patients and to assess the effects of vitamin D supplementation in pain management in these individuals. We searched PubMed, Physiotherapy Evidence Database (PEDro), and the Cochrane Central Register of Controlled Trials (CENTRAL) for RCTs published in English from 1 January 1990 to 10 July 2022. A total of 434 studies were accessed, of which 14 satisfied the eligibility criteria. In our review three studies, of which two had the best-quality evidence, a correlation between diffuse muscle pain and 25OHD deficiency was confirmed. Six studies, of which four had the best-quality evidence, demonstrated that appropriate supplementation may have beneficial effects in patients with established blood 25OHD deficiency. Eight studies, of which six had the best-quality evidence, demonstrated that 25OHD supplementation results in pain reduction. Our results suggest a possible role of vitamin D supplementation in alleviating the pain associated with FMS and CMP, especially in vitamin D-deficient individuals.

Conditional Recommendations for Specific Dietary Ingredients as an Approach to Chronic Musculoskeletal Pain: Evidence-Based Decision Aid for Health Care Providers, Participants, and Policy Makers

OBJECTIVE

Approximately 55-76% of Service members use dietary supplements for various reasons; although such use has become popular for a wide range of pain conditions, decisions to use supplements are often driven by information that is not evidence-based. This work evaluates whether the current research on dietary ingredients for chronic musculoskeletal pain provides sufficient evidence to inform decisions for practice and self-care, specifically for Special Operations Forces personnel.

METHODS

A steering committee convened to develop research questions and factors required for decision-making. Key databases were searched through August 2016. Eligible systematic reviews and randomized controlled trials were assessed for methodological quality. Meta-analysis was applied where feasible. GRADE was used to determine confidence in the effect estimates. A decision table was constructed to make evidence-informed judgments across factors required for decision-making, and recommendations were made for practice and self-care use.

RESULTS

Nineteen dietary ingredients were included. Conditional evidence-based recommendations were made for the use of avocado soybean unsaponifiables, capsaicin, curcuma, ginger, glucosamine, melatonin, polyunsaturated fatty acids, and vitamin D. In these cases, desirable effects outweighed undesirable effects, but there was uncertainty about the trade-offs, either because the evidence was low quality or because benefits and downsides were closely balanced.

CONCLUSIONS

The evidence showed that certain dietary ingredients, when taken as part of a balanced diet and/or as a supplement (e.g., pill, tablet, capsule, cream), may alleviate musculoskeletal pain with no to minimal risk of harm. This finding emphasizes and reinforces the critical importance of shared decision-making between Operators and their health care providers.

Guideline summary review: an evidence-based clinical guideline for the diagnosis and treatment of low back pain

BACKGROUND CONTEXT

The North American Spine Society's (NASS) Evidence Based Clinical Guideline for the Diagnosis and Treatment of Low Back Pain features evidence-based recommendations for diagnosing and treating adult patients with nonspecific low back pain. The guideline is intended to reflect contemporary treatment concepts for nonspecific low back pain as reflected in the highest quality clinical literature available on this subject as of February 2016.

PURPOSE

The purpose of the guideline is to provide an evidence-based educational tool to assist spine specialists when making clinical decisions for adult patients with nonspecific low back pain. This article provides a brief summary of the evidence-based guideline recommendations for diagnosing and treating patients with this condition.

STUDY DESIGN

This is a guideline summary review.

METHODS

This guideline is the product of the Low Back Pain Work Group of NASS' Evidence-Based Clinical Guideline Development Committee. The methods used to develop this guideline are detailed in the complete guideline and technical report available on the NASS website. In brief, a multidisciplinary work group of spine care specialists convened to identify clinical questions to address in the guideline. The literature search strategy was developed in consultation with medical librarians. Upon completion of the systematic literature search, evidence relevant to the clinical questions posed in the guideline was reviewed. Work group members utilized NASS evidentiary table templates to summarize study conclusions, identify study strengths and weaknesses, and assign levels of evidence. Work group members participated in webcasts and in-person recommendation meetings to update and formulate evidence-based recommendations and incorporate expert opinion when necessary. The draft guideline was submitted to an internal and external peer review process and ultimately approved by the NASS Board of Directors.

RESULTS

Eighty-two clinical questions were addressed, and the answers are summarized in this article. The respective recommendations were graded according to the levels of evidence of the supporting literature.

CONCLUSIONS

The evidence-based clinical guideline has been created using techniques of evidence-based medicine and best available evidence to aid practitioners in the diagnosis and treatment of adult patients with nonspecific low back pain. The entire guideline document, including the evidentiary tables, literature search parameters, literature attrition flowchart, suggestions for future research, and all of the references, is available electronically on the NASS website at https://www.spine.org/ResearchClinicalCare/QualityImprovement/ClinicalGuidelines.aspx.

From being restrained to recapturing vitality: non-western immigrant women's experiences of undergoing vitamin D treatment after childbirth

Purpose: Vitamin D deficiency is a complex topic in human health and ill-health and has been studied in a variety of contexts and populations. Few studies examine Vitamin D deficiency among non-western immigrant women and even fewer examine women's perspective on daily life while living with low vitamin D levels after childbirth and undergoing vitamin D treatment. The aim was, therefore, to explore health and ill-health among non-western immigrant women living with low vitamin D levels after childbirth and reaching normalized levels after one year of vitamin D treatment. Method: An explorative qualitative study using qualitative content analysis. Six women aged 25 to 38 years, diagnosed with low 25-hydroxyvitamin D levels during pregnancy, were recruited after having undergone vitamin D treatment. Results: The women told about living a restrained life which gradually transformed into an experience of recaptured vitality. They also experienced a need for continuity in medication, as an interruption of treatment meant returning symptoms. Conclusion: In this study, non-western immigrant women described benefits in everyday life, increased strength, relieved pain and improved sleep quality. The findings can provide valuable knowledge for healthcare providers meeting women with physical weakness, musculoskeletal pain and/or poor sleep quality after childbirth. Further studies using a longitudinal design and larger samples are warranted.

Vitamin D supplementation may improve back pain disability in vitamin D deficient and overweight or obese adults

Back pain is currently the greatest cause of disability worldwide, and there are very limited therapeutic options available. Vitamin D deficiency and obesity are both risk factors for back pain. The few randomised controlled trials examining the effects of vitamin D supplementation on back pain have methodological limitations and largely include non-vitamin D deficient participants. Thus, the aim of this study was to determine whether vitamin D supplementation improves back pain symptoms in vitamin D deficient and overweight or obese, otherwise healthy adults. Sixty-five overweight or obese adults (BMI ≥ 25 kg/m²) with vitamin D deficiency (25-hydroxyvitamin D [25(OH)D] concentrations ≤50 nmol/L) were randomised to a bolus oral dose of 100,000 IU followed by 4000 IU cholecalciferol/day or matching placebo for 16 weeks. We measured 25(OH)D concentrations (chemiluminescent immunoassays) and self-reported back pain (Chronic Pain Grade Questionnaire) before and after the intervention. Lifestyle habits including sun exposure, physical activity, and diet were collected using questionnaires. Fifty-four participants completed the study, of which 49 had complete data for back pain and were included in the present analyses (31 M/18 F; mean ± SD age: 31.8 ± 8.9 years; BMI: 31.1 ± 4.5 kg/m²). After the 16-week intervention, 25(OH)D levels increased significantly with vitamin D supplementation compared with placebo (55.7 ± 20.9 versus 3.9 ± 14.4 nmol/L, respectively, p < 0.001). There were no significant differences between vitamin D and placebo groups in change in back pain intensity or disability scores (all p > 0.05). However, in those with 25(OH)D concentrations <30 nmol/L at baseline (n = 20), there was a significantly greater reduction in back pain disability scores in the vitamin D group compared with placebo, after adjusting for important covariates known to affect vitamin D status and/or back pain (b [95%CI] = -11.6 [-22.4, -0.8], p = 0.04). Our findings suggest that vitamin D supplementation in overweight or obese and markedly vitamin D deficient adults (25(OH)D <30 nmol/L) may improve back pain disability. Although treating severe vitamin D deficiency is recommended for optimising bone health, this study suggests it may also improve back pain. Hence, testing for vitamin D deficiency in those with back pain who are overweight or obese may be warranted.

Assessment of research waste part 2: wrong study populations- an exemplar of baseline vitamin D status of participants in trials of vitamin D supplementation

BACKGROUND

Research waste can occur when trials are conducted in the wrong populations. Vitamin D deficient populations are most likely to benefit from vitamin D supplementation. We investigated waste attributable to randomised controlled trials (RCTs) of supplementation in populations that were not vitamin D deficient.

METHODS

In December 2015, we searched Pubmed, recent systematic reviews, and three trial registries for RCTs of vitamin D with clinical endpoints in adults, and 25-hydroxvitamin D (25OHD) survey data relevant to large (N ≥ 1000) RCTs. We investigated the proportion of RCTs that studied vitamin D deficient populations, temporal trends in baseline 25OHD, and whether investigators in large RCTs considered relevant 25OHD survey data or systematic reviews in their trial justifications.

RESULTS

Of 137 RCTs of vitamin D with clinical endpoints, 118 (86%) reported baseline mean/median 25OHD, which was < 25, 25-49, 50-74, and ≥ 75 nmol/L in 12 (10%), 62 (53%), 36 (31%), and 8 (7%) RCTs, respectively. In 70% of RCTs, baseline 25OHD was > 40 nmol/L. Baseline 25OHD increased over time. Before 2006, 38%, 62%, 0% and 0% of RCTs had baseline 25OHD < 25, 25-49, 50-74, and ≥ 75 nmol/L respectively; in 2011-15, the respective proportions were 9%, 49%, 37%, and 6%. Of 12 RCTs with baseline 25OHD < 25 nmol/L, 8 had neutral findings. Of 25 large RCTs (18 completed, 7 ongoing), 1 was undertaken in a vitamin D deficient population, 3 in vitamin D insufficient populations, and 17 had, or probably will have, baseline 25OHD > 40 nmol/L. 44% (8/18) of large completed RCTs cited relevant prior population 25OHD data, and only 3/10 (30%) relevant prior systematic reviews.

CONCLUSIONS

Up to 70% of RCTs of vitamin D with clinical endpoints, 71% of large completed RCTs, and 100% of ongoing large RCTs could be considered research waste because they studied cohorts that were not vitamin D deficient.

Lower pain and higher muscular strength in immigrant women with vitamin D deficiency following vitamin D treatment

BACKGROUND

Vitamin D deficiency is common among immigrants in the Nordic region. It may lead to osteomalacia with severe musculoskeletal pain. There are reports that vitamin D deficiency without osteomalacia may lead to pain but little is known of the effect of treatment.

OBJECTIVE

To investigate whether a moderate dose of cholecalciferol and calcium improves strength and pain in a group of vitamin D deficient women.

DESIGN

Twentyfive immigrant women with vitamin D deficiency diagnosed during pregnancy were treated postpartum with a daily dose of 1,600 IU cholecalciferol and 1,000 mg of calcium. They were examined at the start of treatment and again after 3 months of treatement and the results were statistically compared.

SETTING

Southern parts of Stockholm.

MAIN OUTCOME MEASURES

Serum 25-hydroyvitamin D (25(OH)D), serum-parathyroid hormone (PTH), pain measured by a visual analogue scale (VAS), musculoskeletal strength by performance on a chair stand test (seconds), and bone tenderness by pressure algometer (kilo-Pascal).

RESULTS

Following the treatment, the 21 women attending had lowered cm in VAS, improved musculoskeletal strength, - and 25(OH)D levels were normalized.

CONCLUSIONS

A moderate dose of vitamin D normalized l vitamin D levels, improved muscular strength and reduced pain in this group of vitamin D deficient immigrant women.

Is there an association between vitamin D status and risk of chronic low back pain? A nested case-control analysis in the Nord-Trøndelag Health Study

OBJECTIVES

To explore potential associations between vitamin D status and risk of chronic low back pain (LBP) in a Norwegian cohort, and to investigate whether relationships depend on the season of blood sample collection.

DESIGN

A nested case-control study in a prospective data set.

SETTING

The Norwegian community-based Nord-Trøndelag Health Study (HUNT). Data were collected in the HUNT2 (1995-1997) and HUNT3 (2006-2008) surveys.

MAIN OUTCOME MEASURE

Chronic LBP, defined as LBP persisting at least 3 months continuously during the past year.

PARTICIPANTS

Among individuals aged 19-55 years without LBP in HUNT2, a data set was generated including 1685 cases with LBP in HUNT3 and 3137 controls without LBP.

METHODS

Blood samples from the participants collected in HUNT2 were analysed for serum 25-hydroxyvitamin D (25(OH)D) level. Associations with LBP in HUNT3 were evaluated by unconditional logistic regression analysis with adjustment for age, sex, work status, physical activity at work and in leisure time, education, smoking, and body mass index.

RESULTS

No association between vitamin D status and risk of chronic LBP was found in the total data set (OR per 10 nmol/L 25(OH)D=1.01, 95% CI 0.97 to 1.06) or in individuals with blood samples collected in summer/autumn (OR per 10 nmol/L 25(OH)D=0.99, 95% CI 0.93 to 1.06). For blood samples drawn in winter/spring, associations differed significantly between women and men (p=0.004). Among women a positive association was seen (OR per 10 nmol/L 25(OH)D=1.11, 95% CI 1.02 to 1.20), but among men no significant association was observed (OR per 10 nmol/L 25(OH)D=0.90, 95% CI 0.81 to 1.01).

CONCLUSIONS

Overall, no association between vitamin D status and risk of LBP was demonstrated. The association suggested in women for the winter/spring season cannot be regarded as established.

Evaluation of vitamin D levels in patients with chronic low back-leg pain

OBJECTIVE

We aimed to examine the relationship between the levels of vitamin D and patients with chronic low back-leg pain (CLBLP) and to investigate its effects on pain and functional capacity.

METHODS

145 patients (female/male:103/42) with CLBLP, aged between 35 and 65 years (mean age: 53,06 ± 8,14), participated in the study. Visual Analog Pain Scale (VAS) was used to measure the state of pain. Pain-related functional capacity was evaluated through Oswestry Disability Index (ODI). Patients were classified into three groups based on their serum vitamin D levels: normal (≥30 ng/ml), vitamin D insufficiency (21-29 ng/ml), and vitamin D deficiency (≤20 ng/ml).

RESULTS

We found that 22,8% of patients (n:33) had vitamin D deficiency, 42,8% (n:62) had vitamin D insufficiency, and 34,5% (n:50) had normal levels of vitamin D. VAS scores were 4,75 ± 0,93; 4,66 ± 0,97 and 4,52 ± 0,90 for patients with vitamin D deficiency, vitamin D insufficiency, and normal levels of vitamin D, respectively. We found that there was no significant relationship between vitamin D level and VAS score (p>0,05). ODI scores were 18,78 ± 7,89; 15,46 ± 5,57 and 14,52 ± 7,19 for patients with vitamin D deficiency, vitamin D insufficiency, and normal levels of vitamin D, respectively. CLBLP-related functional capacity was found to be significantly lower in patients with vitamin D deficiency when compared to other two groups (p < 0,05).

CONCLUSION

Vitamin D deficiency may lead to lower functional capacity, and clinically, Vit D levels should be checked in musculoskeletal pain patients at risk of Vit D deficiency.

LEVEL OF EVIDENCE

Level IV, Diagnostic study.

Mechanical factors and vitamin D deficiency in schoolchildren with low back pain: biochemical and cross-sectional survey analysis

OBJECTIVE

This study was designed to evaluate the role of vitamin D, muscle fatigue biomarkers, and mechanical factors in the progression of low back pain (LBP) in schoolchildren.

BACKGROUND

Children and adolescents frequently suffer from LBP with no clear clinical causes, and >71% of schoolchildren aged 12-17 years will show at least one episode of LBP.

MATERIALS AND METHODS

A total of 250 schoolchildren aged 12-16 years were randomly enrolled in this study. For all schoolchildren height, weight, percentage of daily sun exposure and and areas of skin exposed to sun, method of carrying the bag, and bag weight and type were recorded over a typical school week. Pain scores, physical activity (PA), LBP, serum vitamin 25(OH)D level, serum bone-specific alkaline phosphatase, creatine kinase (CK), and lactate dehydrogenase (LDH) activities and calcium (Ca) concentrations were estimated using prevalidated Pain Rating Scale, modified Oswestry Low Back Pain Disability Questionnaire, short-form PA questionnaire, and colorimetric and immunoassay techniques.

RESULTS

During the period of October 2013-May 2014, LBP was estimated in 52.2% of the schoolchildren. It was classified into moderate (34%) and severe (18%). Girls showed a higher LBP (36%) compared with boys (24%). In schoolchildren with moderate and severe LBP significantly higher (P=0.01) body mass index, waist, hip, and waist-to-hip ratio measurements were observed compared with normal schoolchildren. LBP significantly correlated with less sun exposure, lower PA, sedentary activity (TV/computer use), and overloaded school bags. In addition, schoolchildren with severe LBP showed lower levels of vitamin 25(OH)D and Ca and higher levels of CK, LDH, and serum bone-specific alkaline phosphatase compared with moderate and healthy schoolchildren. Stepwise regression analysis revealed that age, gender, demographic parameters, PA, vitamin D levels, Ca, CK, and LDH associated with ~56.8%-86.7% of the incidence of LBP among schoolchildren.

CONCLUSION

In children and adolescents, LBP was shown to be linked with limited sun exposure, inadequate vitamin D diets, adiposity, lower PA, sedentary lifestyles, vitamin 25 (OH) D deficiency, and lower levels of Ca, CK, and LDH.

No association between level of vitamin D and chronic low back pain in Swedish primary care: a cross-sectional case-control study

OBJECTIVE

Assessment of vitamin D levels and deficiency status in individuals with chronic low back pain (CLBP) in a Swedish general population, compared with controls matched for sex and age.

DESIGN

Cross-sectional case-control study.

SETTING

Primary care, southern Sweden.

SUBJECTS

Participants (n = 44) with self-reported low back pain for at least 3 months and individually sex- and age-matched controls without a chronic pain condition (n = 44), recruited from the general population by random letter of invitation.

MAIN OUTCOME MEASURE

Association between vitamin D level and CLBP when adjusting for possible confounders in a multivariate forward conditional logistic regression model.

RESULTS

Mean S-25-hydroxyvitamin D levels were 81 and 80 nmol/L in the CLBP and control group, respectively. The prevalence of vitamin D deficiency was low and similar in the CLBP group and the control group. Vitamin D level was not associated with CLBP when potential confounders were taken into account.

CONCLUSIONS

No difference in vitamin D levels between participants with CLBP and matched controls could be demonstrated in the present sample. Assessment of vitamin D level and deficiency status may be of questionable value in the management of CLBP in primary care settings at similar latitudes, unless there are additional risk factors for deficiency or specific indicators of osteomalacia. Key points Vitamin D deficiency is common and reported in many chronic pain conditions, including chronic low back pain (CLBP), but evidence for an association and causality is insufficient. • The present study found no association between vitamin D levels and CLBP in a case-control sample of 44 + 44 individuals from the Swedish general population. • Prevalence of vitamin D deficiency was low and comparable in individuals with CLBP and controls without chronic pain, matched for sex and age. • Assessment of vitamin D status, for the purpose of finding and treating an underlying cause of pain, may be of limited value in the management of CLBP in primary care settings at similar latitudes.

Correlation of Vitamin D and Body Mass Index with Modic Changes in Patients with Non-Specific Low Back Pain in a Sub-Tropical Asian Population

Study Design

Cross-sectional study by non-probability consecutive sampling.

Purpose

The objective of this study was to assess body mass index (BMI) and investigate vitamin D levels in patients with low back pain (LBP) and study a possible relationship with myopathy-related symptoms and Modic changes.

Overview of Literature

LBP is a multifactorial problem and the search for its patho-anatomical causes is ongoing. Modic changes seem to be a cause of back pain but the pathological mechanisms underlying this are not completely defined. Hypovitaminosis D and obesity have also been shown to cause chronic musculoskeletal pain. The relationship between vitamin D deficiency and BMI with Modic changes has not been studied in detail.

Methods

Three hundred and sixteen patients with chronic LBP was selected for the study by non-probability consecutive sampling. The study was conducted over a period of 12 months from January 2014 to December 2014 at St. John's Medical College, Banglore. Questionnaires were provided to the participants and demographic information, symptoms, weight and height were recorded from the study subjects. BMI was calculated. Serum vitamin D level was assessed and Modic changes studied on magnetic resonance imaging. Correlations between vitamin D, BMI and Modic changes were studied using correlation coefficients and odds ratios obtained from logistic regression.

Results

Two hundred and fifty-six out of 316 patients (80%) had low vitamin D. 83% of patients with BMI>25 kg/m² had low vitamin D levels as compared to 69% with BMI<25 kg/m². Statistically significant correlation coefficients were found between vitamin D levels, BMI and Modic changes. Significant association was found between low vitamin D levels and Modic changes (odds ratio 1.75).

Conclusions

Vitamin D deficiency and obesity have significant relations with LBP. Low vitamin D levels is associated with Modic changes but whether they represent a subgroup of patients whose low backpain is associated with low vitamin D needs to be further evaluated.

Vitamin D and inflammatory diseases

Beyond its critical function in calcium homeostasis, vitamin D has recently been found to play an important role in the modulation of the immune/inflammation system via regulating the production of inflammatory cytokines and inhibiting the proliferation of proinflammatory cells, both of which are crucial for the pathogenesis of inflammatory diseases. Several studies have associated lower vitamin D status with increased risk and unfavorable outcome of acute infections. Vitamin D supplementation bolsters clinical responses to acute infection. Moreover, chronic inflammatory diseases, such as atherosclerosis-related cardiovascular disease, asthma, inflammatory bowel disease, chronic kidney disease, nonalcoholic fatty liver disease, and others, tend to have lower vitamin D status, which may play a pleiotropic role in the pathogenesis of the diseases. In this article, we review recent epidemiological and interventional studies of vitamin D in various inflammatory diseases. The potential mechanisms of vitamin D in regulating immune/inflammatory responses in inflammatory diseases are also discussed.