Low levels of vitamin D and worsening of knee osteoarthritis: results of two longitudinal studies

Prevalence of serum vitamin D and B12, Ca, P, Mg levels and rheumatoid factor status in the patients with bilateral TMJ-OA and their correlations with clinical and radiological findings

OBJECTIVE

To evaluate the prevalence of serum vitamin D and B12, calcium, phosphorus, magnesium levels, and rheumatoid factor (RF) status in patients with bilateral temporomandibular joint osteoarthritis (TMJ-OA) and their correlations with clinical and radiological findings.

METHODS

The clinical and radiologic findings and serum vitamin and mineral levels of 90 patients diagnosed with bilateral TMJ-OA were recorded. Descriptive statistics and the Spearman's Rho correlation test were performed.

RESULTS

Low serum vitamin D and B12 levels were detected in 82 (91.1%) and 74 (82.2%) patients. Calcium and phosphorus levels were seen at low rates. RF status was recorded as unfavorable in all patients. Correlations were found between age and the serum vitamin and mineral levels, except phosphorus. Low serum vitamin D levels correlated with pain complaints at rest and painless MIO. Serum B12 levels correlated with condylar erosion. Serum magnesium levels correlated with painful MIO and condylar osteophyte.

CONCLUSION

Patients with bilateral TMJ-OA showed a high prevalence of low serum vitamin D and B12 levels.

Vitamin D Deficiency after Anterior Cruciate Ligament Reconstruction Associates with Knee Osteoarthritis: A Retrospective Study

BACKGROUND/OBJECTIVES

The objective of this study was to test the hypothesis that vitamin D deficiency (i.e., serum 25-hydroxyvitamin D (25(OH)D) ≤ 20 ng/mL) associates with the increased occurrence and shortened time to a knee osteoarthritis (OA) diagnosis after anterior cruciate ligament reconstruction (ACLR).

METHODS

This study consisted of a retrospective, case-control design. The inclusion criteria consisted of (1) patients (≥18 y) who underwent arthroscopic ACLR with (cases; n = 28) and without (controls; n = 56) a subsequent knee OA diagnosis (≥90 d from the date of ACLR) and (2) with a documented serum 25(OH)D concentration after ACLR (and before a knee OA diagnosis for the cases). Controls were matched (2:1) to cases based on sex, age at ACLR, date of ACLR, and body mass index. After matching, patients were separated into two groups: (1) vitamin D deficient (serum 25(OH)D ≤ 20 ng/mL) or (2) non-vitamin D deficient (serum 25(OH)D > 20 ng/mL). Data were extracted from the medical records.

RESULTS

Thirty-one percent (n = 26) of patients included were vitamin D deficient. Fifty percent (n = 13) of the vitamin D deficient and twenty-six percent (n = 15) of the non-vitamin D deficient patients were subsequently diagnosed with knee OA (p = 0.03). Time from ACLR to a knee OA diagnosis was significantly (p = 0.02) decreased in the vitamin D deficient (OA-free interval, 95% confidence interval [CI] = 7.9 to 10.9 y) compared to the non-vitamin D deficient group (OA-free interval, 95% CI = 10.5 to 12.5 y).

CONCLUSIONS

Vitamin D deficiency after ACLR may serve as a prognostic biomarker for knee OA following ACLR.

Exploration beyond osteoarthritis: the association and mechanism of its related comorbidities

Osteoarthritis is the most prevalent age-related degenerative joint disease and a leading cause of pain and disability in aged people. Its etiology is multifaceted, involving factors such as biomechanics, pro-inflammatory mediators, genetics, and metabolism. Beyond its evident impact on joint functionality and the erosion of patients' quality of life, OA exhibits symbiotic relationships with various systemic diseases, giving rise to various complications. This review reveals OA's extensive impact, encompassing osteoporosis, sarcopenia, cardiovascular diseases, diabetes mellitus, neurological disorders, mental health, and even cancer. Shared inflammatory processes, genetic factors, and lifestyle elements link OA to these systemic conditions. Consequently, recognizing these connections and addressing them offers opportunities to enhance patient care and reduce the burden of associated diseases, emphasizing the need for a holistic approach to managing OA and its complications.

Relationship between serum vitamin D levels and the prevalence of knee osteoarthritis: A retrospective study on 3424 subjects

BACKGROUND

The extent of the association between vitamin D deficiency and knee osteoarthritis remains inadequately understood.

OBJECTIVE

This study aimed to elucidate the relationship between vitamin D levels and knee osteoarthritis through a cross-sectional analysis.

METHODS

This retrospective study involved an analysis of knee radiographs and serum 25-hydroxyvitamin D3 (25-(OH) vitamin D3) levels in a cohort of 3424 individuals (2901 women and 523 men). Knee osteoarthritis severity was evaluated using the Kellgren-Lawrence radiological scoring system.

RESULTS

Of the participants, 49.2% (n= 1,683) were diagnosed with knee osteoarthritis. Among these patients, the levels of adjusted 25-(OH) vitamin D3 were significantly lower (p< 0.001). Regression analysis revealed a significant association between vitamin D deficiency and knee osteoarthritis, with an adjusted odds ratio (OR) of 1.7 (95% CI: 1.5-2.0; p< 0.001). Notably, a stronger association was observed between vitamin D deficiency and knee osteoarthritis in women under 65 compared to those aged 65 and above.

CONCLUSIONS

The findings of this study indicate a higher prevalence of vitamin D deficiency in patients with knee osteoarthritis. Maintaining adequate serum 25-(OH) vitamin D3 levels may prevent knee osteoarthritis, especially in women below 65.

Vitamin D and autophagy in knee osteoarthritis: A review

Knee osteoarthritis (KOA), the highly prevalent degenerative disease affecting the joint, perpetually devastates the health of the elderly. Of various mechanisms known to participate in KOA etiology, apoptosis of chondrocytes is widely regarded as the primary cause of cartilage degradation. It has been suggested that the induction of autophagy in chondrocytes could potentially prolong the progression of KOA by modulating intracellular metabolic processes, which may be helpful for ameliorating chondrocyte apoptosis and eventual cartilage degeneration. Autophagy, a physiological process characterized by intracellular self-degradation, has been reportedly implicated in various pathologic conditions including KOA. Interestingly, vitamin D has been shown to regulate autophagy in human chondrocytes through multiple pathways, specifically AMPK/mTOR signaling pathway. This observation underscores the potential of vitamin D as a novel approach for restoring the functionality and survivability of chondrocytes in KOA. Supporting vitamin D's clinical significance, previous studies have demonstrated its substantial involvement in the symptoms and irregular joint morphology observed in KOA patients, strengthening potential therapeutic efficacy of vitamin D in treatment of KOA. Herein, the purpose of this review was to determine the mechanisms underlying the multi-processes of vitamin D implicated in autophagy in several cells including chondrocytes, which would bring unique insights into KOA pathogenesis.

The burden of osteoarthritis: Is it a rising problem?

The objective of this review is to provide an overview of the current status of osteoarthritis (OA) as one of the most common joint disorders worldwide. Despite being the 11th cause of disability globally, there has been an increase in the prevalence, annual incidence, and years lived with disability of OA, particularly in developed and developing countries. Erosive hand OA, which affects approximately 10% of the general population, has been associated with a higher clinical burden compared to non-erosive hand OA. Patients with knee and hip OA, but not hand OA, are also at an increased risk of cardiovascular disease and all-cause mortality. Furthermore, OA has a significant contribution to healthcare costs in most countries. The recent COVID-19 pandemic has further exacerbated the disease burden of OA patients due to limited access to medical and surgical treatment. With increasing life expectancy and the aging of the global population, the burden of OA is expected to worsen. Therefore, this review highlights the importance of improving population and policymaker awareness of risk factors, such as obesity and injury, as well as early intervention and management of OA to control the future burden of the disease.

Association between serum 25-hydroxyvitamin D and osteoarthritis: A national population-based analysis of NHANES 2001-2018

Background

Previous studies have not provided a consensus on the effect of serum 25-hydroxyvitamin D [25(OH)D] on osteoarthritis (OA). We aimed to evaluate the association using a large, nationally representative sample.

Methods

The cross-sectional data were obtained from the 2001 to 2018 National Health and Nutrition Examination Survey (NHANES). Individuals aged ≥40 years who had information of serum 25(OH)D, self-report OA, and related covariates were included. Multivariable logistic regression analysis was employed to assess the association between serum 25(OH)D and osteoarthritis.

Results

Among the 21,334 participants included (weighted mean age, 56.9 years; 48.5% men), the proportion of participants with high serum 25(OH)D concentrations (≥100 nmol/L) increased significantly from 4.2% in 2001-2006 to 18.8% in 2013-2018. Higher serum 25(OH)D levels were associated with more osteoarthritis prevalence in fully adjusted model (odd ratio [OR] 1.25 [95% CI: 1.10, 1.43] for the 50-75 nmol/L group; OR 1.62 [95% CI: 1.42, 1.85] for the 75-100 nmol/L group; OR 1.91 [95% CI: 1.59, 2.30] for the ≥100 nmol/L group; with <50 nmol/L group as the reference) (p < 0.001 for trend). The association was consistent across several sensitivity analyses, including propensity score methods and excluding participants who had received vitamin D supplement. In subgroup analysis, the OR for the association increased significantly with body mass index (BMI) (BMI < 25 kg/m², 1.01 [95% CI: 1.04, 1.08]; BMI 25-30 kg/m², 1.05 [95% CI: 1.01, 1.08]; BMI ≥ 30 kg/m², 1.10 [95% CI: 1.06, 1.13]; p = 0.004 for interaction).

Conclusion

There was a positive correlation between serum 25(OH)D and osteoarthritis with a possible modification by BMI. Our finding raises concerns about the potential adverse effects of high serum 25(OH)D on osteoarthritis, particularly among obese individuals. More well-designed studies are still needed to validate our findings in future.

Older Korean men with inadequate vitamin D status have lower odds of radiologic osteoarthritis

Most studies on osteoarthritis (OA) and vitamin D status were performed in Whites with relatively adequate vitamin D status. Associations may differ by baseline 25-hydroxyvitamin D (25(OH)D) and race. We assessed the odds of OA and joint pain according to vitamin D status in Korean adults ≥ 50 years of age in the nationally representative Korea National Health and Nutrition Examination Survey (n = 8575). Agreement between radiologic OA (ROA) and self-reported OA were also assessed. Multivariate logistic regression was performed and participants were stratified by sex. Adults with serum 25(OH)D < 12 ng/mL and 12 to < 20 ng/mL had 26% and 18% lower odds of knee ROA, respectively, compared to those with 25(OH)D ≥ 20 ng/mL. Similar results were observed in men, but not women. No associations were found between 25(OH)D and knee ROA severity, lumbar spine ROA, symptomatic OA, or knee pain. Sensitivity of self-reported OA was low (27%), indicating a weak possibility of reverse causation. Prospective studies are required to identify the possible causality of vitamin D on OA in Korean men.

Nutraceutical Approach to Chronic Osteoarthritis: From Molecular Research to Clinical Evidence

Osteoarthritis (OA) is a degenerative inflammatory condition of the joint cartilage that currently affects approximately 58 million adults in the world. It is characterized by pain, stiffness, and a reduced range of motion with regard to the arthritic joints. These symptoms can cause in the long term a greater risk of overweight/obesity, diabetes mellitus, and falls and fractures. Although the current guidelines for the treatment of OA suggest, as the gold standard for this condition, pharmacological treatment characterized by non-steroidal anti-inflammatory drugs (NSAID), opioids, and cyclooxygenase (COX)-2-specific drugs, a great interest has been applied to nutraceutical supplements, which include a heterogeneous class of molecules with great potential to reduce inflammation, oxidative stress, pain, and joint stiffness and improve cartilage formation. The purpose of this review is to describe the potential application of nutraceuticals in OA, highlighting its molecular mechanisms of actions and data of efficacy and safety (when available).

Vitamin C supplementation for the treatment of osteoarthritis: perspectives on the past, present, and future

According to the US Centers for Disease Control and Prevention (CDC), an estimated 14% of adults in the United States have either been diagnosed with osteoarthritis (OA) or have symptoms suggestive of the disease. The CDC also points out that the incidence of OA has been gradually increasing over the past 30 years. What is more worrisome is that this trend is going to accelerate due to the aging demographics of the United States and the increasing prevalence of obesity seen in the country. The need for better preventive treatments and efficacious therapeutics are direly needed to combat this public health crisis. Among the possible treatments being hypothesized, antioxidant supplementation has become one of the most widely studied over the past decade due to its ability to attenuate reactive oxygen species (ROS) formation within chondrocytes, a critical step in the pathogenesis of this disease. Vitamin C has emerged as among the most promising of the antioxidant group, with many animal and human studies having been conducted in recent years. Although many of the studies have shown encouraging results in terms of preventing OA, others have reached opposite conclusions, thus making the data controversial. However, after reviewing several of these studies, we hypothesize that certain parameters may not have been properly considered during data collection. In the end, more randomized placebo-controlled trials in humans are desperately needed in order to fully understand whether vitamin C therapy is efficacious in treating and/or preventing OA.

Risk of Osteoarthritis is Positively Associated with Vitamin D Status, but Not Bone Mineral Density, in Older Adults in the United States

OBJECTIVE

We examined the risk of osteoarthritis (OA) according to vitamin D status and bone mineral density (BMD) using a cross-sectional nationally representative database.

METHODS

National Health and Nutrition Examination Survey (NHANES) data from 2007 to 2010 were used to assess the relationship between OA and vitamin D status in adults aged ≥40 years (n = 2934). NHANES data from 2005 to 2010 and 2013 to 2014 were analyzed to investigate the association between OA and BMD (n = 5949). Vitamin D status was categorized as serum 25-hydroxyvitamin D (25OHD) <20 ng/mL or ≥20 ng/mL. Bone health was classified according to T-score (normal, osteopenia, or osteoporosis) and BMD tertile. Risk of OA was assessed using logistic regression and adjusted for covariates.

RESULTS

Participants with serum 25OHD <20 ng/mL had a 37% lower risk of OA (95% confidence interval (CI) [0.39-0.99], P = 0.046). When stratified by sex, the odds ratio for OA in men with lower vitamin D status was 0.35 (95% CI [0.15-0.81], P = 0.02). No association was found in women. The risk for OA did not differ according to BMD tertile or T-score classification.

CONCLUSIONS

The risk of OA is lower in older men with 25OHD less than 20 ng/mL but not in older women. Bone mineral density is not associated with OA risk in older adults in the United States.

Does vitamin D improve symptomatic and structural outcomes in knee osteoarthritis? A systematic review and meta-analysis

OBJECTIVE

To provide evidence on the effects of vitamin D supplementation on knee osteoarthritis (KOA) and new targets for clinical prevention and treatment of KOA.

METHOD

The PubMed, Embase, Web of science, Wanfang, CNKI and SinoMed databases were retrieved to investigate the effects of vitamin D supplementation on patients with KOA. The search time was from databases establishment to 15 November 2020. RevMan5.3 software was used for meta-analysis. The results were expressed as standardized mean difference (SMD) with 95% confidence interval (CI) or weighted mean difference (WMD) with 95% confidence interval (CI).

RESULTS

A total of 1599 patients with osteoarthritis of the knee were included in the study, which involved six articles. The results of the meta-analysis showed that vitamin D supplementation is statistically significant for WOMAC score (SMD = - 0.67, 95% CI - 1.23 to - 0.12) in patients with KOA, including WOMAC pain score (SMD = - 0.32, 95% CI - 0.63 to - 0.02), function score (SMD = - 0.34, 95% CI - 0.60 to - 0.08) and stiffness score (SMD = - 0.13, 95% CI - 0.26 to - 0.01). In subgroup analysis, vitamin D supplementation less than 2000 IU was statistically significant for the reduction of stiffness score (SMD = - 0.22, 95% CI - 0.40 to - 0.04). Vitamin D supplements can reduce synovial fluid volume progression in patients with KOA (SMD = - 0.20, 95% CI - 0.39 to - 0.02). There was no statistical significance in improving tibia cartilage volume (SMD = 0.12, 95% CI - 0.05 to 0.29), joint space width (SMD = - 0.10, 95% CI - 0.26 to 0.05) and bone marrow lesions (SMD = 0.03, 95% CI - 0.26 to 0.31).

CONCLUSION

Vitamin D supplements can improve WOMAC pain and function in patients with KOA. But there is a lack of strong evidence that vitamin D supplementation can prevent structural progression in patients with KOA.

Association of vitamin D and knee osteoarthritis in younger individuals

BACKGROUND

The incidence of primary osteoarthritis knee is gradually increasing among young individuals. The increasing prevalence of obesity, sedentary lifestyle, sporting activity, and vitamin D deficiency (VDD) has been hypothesized for this shifting disease trend. This study was designed to look for the association of serum vitamin D among these young arthritic patients.

AIM

To look for the association of serum vitamin D in younger knee osteoarthritis (KOA) patients.

METHODS

In a 2-year observational study, 146 non-obese KOA patients of 35-60 years were evaluated clinically (Knee injury and Osteoarthritis Outcome Score, KOOS) and radiologically (Kellegren-Lawrence stage, KL). The serum 25(OH)D level of these patients and 146 normal healthy individuals of same age group were estimated.

RESULTS

Both the groups were comparable in terms of age and sex. The average serum 25(OH)D level in healthy individuals and KOA patients was 45.83 ng/mL and 34.58 ng/mL, respectively (P < 0.001). Inadequate serum 25(OH)D level (< 30 ng/mL) was found in 46.57% of KOA patients and 24% of normal healthy participants indicating a significant positive association (odds ratio 2.77, 95%CI: 1.67-4.54, P < 0.001). The 25(OH)D level in KL grade I, II, III and IV was 43.40, 30.59, 31.56 and 33.93 ng/mL respectively (no difference, P = 0.47). Similarly, the KOOS score in sufficient, insufficient and deficient groups were 65.31, 60.36 and 65.31, respectively (no difference, P = 0.051).

CONCLUSION

The serum 25(OH)D level is significantly low in younger KOA patients. However, the clinical and radiological severities have no association with serum vitamin D level.

Associations Between Vitamins C and D Intake and Cartilage Composition and Knee Joint Morphology Over 4 Years: Data From the Osteoarthritis Initiative

OBJECTIVE

To determine the cross-sectional and longitudinal associations of vitamin C and D intake with magnetic resonance imaging (MRI) measures of cartilage composition (T2) and joint structure (cartilage, meniscus, and bone marrow) using data from the Osteoarthritis Initiative (OAI) cohort.

METHODS

A total of 1,785 subjects with radiographic Kellgren/Lawrence knee grades 0-3 in the right knee were selected from the OAI database. Vitamins C and vitamin D intake (diet, supplements, and total) were assessed using the Block Brief 2000 Food Frequency Questionnaire at baseline. The MRI analysis protocol included 3T cartilage T2 quantification and semiquantitative joint morphology gradings (Whole-Organ Magnetic Resonance Imaging Score [WORMS]) at baseline and 4 years. Linear regression was used to assess the association between standardized baseline vitamin intake and both baseline WORMS scores and standardized cartilage T2 values.

RESULTS

Higher vitamin C intake was associated with lower average cartilage T2 values, medial tibia T2 values, and medial tibia WORMS scores (standardized coefficient range -0.07 to -0.05, P < 0.05). Higher vitamin D intake was associated with a lower cartilage WORMS sum score and medial femur WORMS score (standardized coefficient range -0.24 to -0.09, P < 0.05). Consistent use of vitamin D supplements of 400 IU at least once a week over 4 years was associated with significantly less worsening of cartilage, meniscus, and bone marrow abnormalities (odds ratio range 0.40-0.56, P < 0.05).

CONCLUSION

Supplementation with vitamin D over 4 years was associated with significantly less progression of knee joint abnormalities. Given the observational nature of this study, future longitudinal randomized controlled trials of vitamin D supplementation are warranted.

Sleep Quality Is Related to Worsening Knee Pain in Those with Widespread Pain: The Multicenter Osteoarthritis Study

OBJECTIVE

We examined the association between sleep and odds of developing knee pain, and whether this relationship varied by status of widespread pain (WSP).

METHODS

At the 60-month visit of the Multicenter Osteoarthritis Study, sleep quality and restless sleep were each assessed by using a single item from 2 validated questionnaires. Each sleep measure was categorized into 3 levels, with poor/most restless sleep as the reference. WSP was defined as pain above and below the waist on both sides of the body and axially using a standard homunculus, based on the American College of Rheumatology criteria. Outcomes from 60-84 months included (1) knee pain worsening (KPW; defined as minimal clinically important difference in WOMAC pain), (2) prevalent, and (3) incident consistent frequent knee pain. We applied generalized estimating equations in multivariable logistic regression models.

RESULTS

We studied 2329 participants (4658 knees; 67.9 yrs, body mass index 30.9]. We found that WSP modified the relationship between sleep quality and KPW (p = 0.002 for interaction). Among persons with WSP, OR (95% CI) for KPW was 0.53 (0.35-0.78) for those with very good sleep quality (p trend < 0.001); additionally, we found the strongest association of sleep quality in persons with > 8 painful joint sites (p trend < 0.01), but not in those with ≤ 2 painful joint sites. Similar results were observed using restless sleep, in the presence of WSP. The cross-sectional relationship between sleep and prevalence of consistent frequent knee pain was significant.

CONCLUSION

Better sleep was related to less KPW with coexisting widespread pain.

Association between serum Vitamin D deficiency and Knee Osteoarthritis

Objective:

Levels of Vitamin D may influence the development of knee osteoarthritis (OA), which is one of the most common joint diseases. The aim of this study was to investigate the association between serum Vitamin D deficiency and knee OA in Ardabil and Iran.

Methods:

One hundred fifty-eight consecutive patients referred to rheumatology clinic of Ardabil City Hospital were recruited in the study. All the participants underwent x-rays in two anterior-posterior and side views of the knees. Staging of knee OA was done according to Kellgren-Lawrence criteria. Seventy-nine individuals with clinical and radiographic signs of knee OA were defined as the case group, and those without clinical and radiographic signs of the disease were defined as a control group. Haematology and biochemical profile including measurement of 25-hydroxyvitamin D serum level was performed in the participants.

Results:

The mean age of patients and controls were 54.12 ± 4.67 and 55.37 ± 5.12 years, respectively. The average serum vitamin D in OA patients and controls were 26.8±6.2 ng/ml and 28.1±5.3ng/ml, respectively (p=0.36). There was a significant association between serum vitamin D and staging of knee OA (p=0.001). Based on vitamin D levels, most of patients with vitamin D deficiency were in stages III and IV.

Conclusion:

The findings of the study suggest that vitamin D deficiency should be considered in patients with OA and treated accordingly.

Association between Vitamin D and Knee Osteoarthritis: A PRISMA-Compliant Meta-analysis

BACKGROUND

Previous investigations showed inconsistent results for associations between vitamin D and knee osteoarthritis (OA). The present study aimed to make a systematic review and meta-analysis for the association between vitamin D and knee OA.

METHODS

We systematically searched for articles published in the databases PubMed, Web of Science, EMBASE, Medline, and Google Scholar through July 2019. All statistical analyses were made using STATA 12.0 software. The Q test and I² were applied to examine heterogeneities between studies.

RESULTS

The study indicated that there were no significant associations between serum levels of 25-hydroxy (OH) vitamin D and prevalence, incidence or progression of knee radiographic OA (ROA), and joint space narrowing (JSN). However, a subgroup study showed significant associations of low vitamin D levels with the progression of knee OA. Additionally, the present study showed no significant effect of vitamin D supplementation on knee OA.

CONCLUSIONS

The results do not support that serum levels of 25(OH) vitamin D are associated with the risks of knee OA, except perhaps with progression of knee OA. In addition, vitamin D supplementation may not have a clinically significant effect on pain control or structure (tibial cartilage volume and JSW) progression in patients with knee OA. Longer-term clinical trials are essential to explore the effect of vitamin D supplementation on knee OA.

Vitamin D Inhibits Activities of Metalloproteinase-9/-13 in Articular Cartilage In Vivo and In Vitro

Low levels of serum vitamin D have been shown to accelerate progression of osteoarthritis. However, the role of vitamin D in articular cartilage degradation and osteoarthritis development is still unclear. This study investigated the effects of vitamin D on articular cartilage degradation by testing matrix metalloproteinase (MMPs) activities in articular cartilage using the rat vitamin D deficiency model at the animal level and rat articular chondrocytes at the cell level. The in vivo study showed vitamin D deficiency increased the expressions of MMP-9 and MMP-13 in rat articular cartilage, and the increase was inhibited by 1α,25(OH)₂D₃ supplementation. The increased production of MMP-9 and MMP-13 in the articular chondrocytes induced by tumor necrosis factor-α (TNF-α) or phorbol-12-myristate-13-acetate (PMA) was significantly suppressed by concomitant treatment with 1α,25(OH)₂D₃ in vitro. The increased level of C-telopeptide of type II collagen (CTX-II) induced by TNF-α or PMA was also significantly suppressed by concomitant treatment with 1α,25(OH)₂D₃ in vitro. Thus, vitamin D intake may inhibit MMP activities and take part in the process of articular cartilage degeneration and osteoarthritis progression.

Therapeutic and Preventive Potential of Vitamin D Supplementation in Knee Osteoarthritis

Objective

Vitamin D deficiency is linked with pain, function, and radiographic progression of knee osteoarthritis (KOA), but the results of studies addressing the association and effect of vitamin D supplementation for pain, function, quality of life, radiographic disease, and progression are inconsistent. The aim of this review is to determine the therapeutic and preventive potential of vitamin D supplementation in KOA.

Method

Eligible pertinent English language studies published in 2000 and thereafter in Medline/PubMed, Scopus, and Google Scholar were selected by using keywords that include “knee osteoarthritis,” “vitamin D supplementation,” “pain,” “structural abnormalities,” “treatment,” and “progression.”

Results

The results of a few studies showed a preventive potential for vitamin D in KOA, but most of the randomized clinical trials that assessed the therapeutic efficacy of vitamin D supplementation in KOA found no clear therapeutic effect, with the exception of one study that found a small but significant effect of vitamin D on pain and knee function. Nonetheless, the results of a few longitudinal studies as well as systematic reviews are promising and thus encourage further studies. Inconsistent results on the effect of vitamin D on KOA may be attributed to factors such as severity of KOA, baseline level of serum vitamin D, duration of treatment, and vitamin D dosages.

Conclusion

Given the multiple skeletal and extraskeletal benefits of vitamin D supplementation in elderly people, the issue of vitamin D supplementation in KOA requires further study to elucidate the dosage and duration of treatment that provides the most effective therapeutic effect.

Assessment of Vitamin D Supplementation on Articular Cartilage Morphology in a Young Healthy Sedentary Rat Model

Deficiency in vitamin D (Vit D) has been widely associated with several musculoskeletal diseases. However, the effects of the exogenous Vit D supplementation are still unclear in the prevention of the latter, especially in the cartilage developmental period. The aim of this study was to compare the effects of Vit D supplementation and restriction on the articular cartilage development in healthy young sedentary rats. To this aim, twelve nine-week-old healthy Sprague-Dawley male rats were subjected to Vit D-based experimental diets: R, with a content in Vit D of 1400 IU/kg; R-DS, with a Vit D supplementation (4000 IU/kg); R-DR, with a Vit D restriction (0 IU/kg) for 10 weeks. The morphology, thickness and expression of cartilage-associated molecules such as collagen type II/X, lubricin and Vit D receptor (VDR), were assessed. Histological, histomorphometric and immunohistochemical evaluations were made on rat tibial cartilage samples. In the present experimental model, restriction of Vit D intake induced: The lower thickness of cartilage compared both to R (p = < 0.0001) and R-DS (p = < 0.0001); reduction of proteoglycans in the extracellular matrix (ECM) compared both to R (p = 0.0359) and R-DS (p = < 0.0001); decreased collagen II (Col II) with respect both to R (p = 0.0076) and R-DS (p = 0.0016); increased collagen X (Col X) immunoexpression when compared both to R (p = < 0.0001) and R-DS (p = < 0.0001), confirming data from the literature. Instead, supplementation of Vit D intake induced: Higher cartilage thickness with respect both to R (p = 0.0071) and R-DR (p = < 0.0001); increase of ECM proteoglycan deposition compared both to R (p = 0.0175) and R-DR (p = < 0.0001); higher immunoexpression of lubricin with respect both to R (p = 0.001) and R-DR (p = 0.0008). These results suggest that Vit D supplementation with diet, already after 10 weeks, has a favorable impact on the articular cartilage thickness development, joint lubrication and ECM fibers deposition in a young healthy rat model.

Nutrition, osteoarthritis and cartilage metabolism

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease and a leading cause of adult disability. There is no cure for OA and there is no effective treatment to stop its progression. Current pharmacologic treatments such as analgesics and non-steroidal anti-inflammatory drugs may improve the pain and offer some relief but they do not affect the progression of the disease. The chronic intake of these drugs may result in severe adverse events. The aim of this review is to revise the effects of nutrition on cartilage metabolism and OA progression.

METHODS

A systematic literature search was performed including those related to macro- and micro-nutrients' actions on cartilage and OA outcome. We selected peer-reviewed articles reporting the results of human clinical trials.

RESULTS

Glucosamine and chondroitin sulfate have shown to delay OA knee progression in several clinical trials. The effectiveness of some products considered nutraceuticals has been widely reviewed in the literature. This article presents a general description of the effectiveness and mechanism of action of nutrients, vitamins, antioxidants and other natural components considered as part of the normal diet. Many in vitro studies indicate the efficacy of specific nutrients in cartilage metabolism and its involvement in OA. However, rigorous clinical studies needed to evaluate the efficacy of these compounds in humans are still missing. The influence of nutrients and diet on the metabolism of cartilage and OA could represent a long-term coadjuvant alternative in the management of patients with OA. Effects of diet modifications on lipid and cholesterol profiles, adequate vitamin levels and weight reduction in obese patients could influence the course of the disease.

CONCLUSION

This review demonstrates that nutrition can improve the symptoms of OA. Glucosamine and chondroitin sulfate have shown robustly to delay the progression of knee OA in several well-designed studies, however more controlled clinical trials are needed to conclude that nutritional changes slow down the progression of the disease.

Vitamin D and Vitamin D Receptor Gene in Osteoarthritis

Osteoarthritis is a degenerative, painful and irreversible disease that affects millions of people worldwide. The causes and mechanisms of osteoarthritis have not been fully understood. Vitamin D is an essential factor in bone metabolism. Its actions are mediated by the vitamin D receptor, a transcription factor that controls gene expression, thus maintaining calcium and phosphate homeostasis. Vitamin D has been hypothesized to play essential role in a number of musculoskeletal diseases including osteoarthritis, and its deficiency is prevalent among osteoarthritis patients. A large number of studies have been done regarding the effects of vitamin D in pathogenesis and progression of osteoarthritis, as well as its use a therapeutic agent. Up to date, studies have provided controversial results, and no consensus concerning this matter was achieved. With this review, we aim to explore current data on the possible role of vitamin D and its receptor in pathogenesis of osteoarthritis and assess the efficiency of vitamin D supplementation as a therapeutic strategy.

Vitamin D in the Prevention and Treatment of Osteoarthritis: From Clinical Interventions to Cellular Evidence

Older adults are recommended vitamin D to prevent fractures. Though this population is also at risk of osteoarthritis (OA), the effect of vitamin D on OA is unclear and may differ by disease state. The relationship between vitamin D and OA during OA initiation and progression were considered in this narrative review of in vivo and in vitro studies. Regarding OA initiation in humans, the small number of published observational studies suggest a lack of association between induction of OA and vitamin D status. Most randomized controlled trials were performed in White OA patients with relatively high vitamin D status (>50 nmol/L). These studies found no benefit of vitamin D supplementation on OA progression. However, subset analyses and one randomized controlled pilot trial indicated that vitamin D supplementation may alleviate joint pain in OA patients with low vitamin D status (<50 nmol/L). As the etiology of OA is recently being more fully uncovered, better animal and cell models are needed. According to currently available clinical results, evidence is lacking to set a vitamin D level to prevent OA, and increasing vitamin D status above 50 nmol/L does not seem to benefit OA patients.

A correlation between intestinal microbiota dysbiosis and osteoarthritis

Osteoarthritis (OA) is a degenerative disease of the articular cartilage, resulting in pain and total joint disability. Recent studies focused on the role of the metabolic syndrome in inducing or worsening joint damage suggest that chronic low-grade systemic inflammation may represent a possible linking factor. This finding supports the concept of a new phenotype of OA, a metabolic OA. The gut microbiome is fundamental for human physiology and immune system development, among the other important functions. Manipulation of the gut microbiome is considered an important topic for the individual health in different medical fields such as medical biology, nutrition, sports, preventive and rehabilitative medicine. Since intestinal microbiota dysbiosis is strongly associated with the pathogenesis of several metabolic and inflammatory diseases, it is conceivable that also the pathogenesis of OA might be related to it. However, the mechanisms and the contribution of intestinal microbiota metabolites in OA pathogenesis are still not clear. The aim of this narrative review is to review recent literature concerning the possible contribution of dysbiosis to OA onset and to discuss the importance of gut microbiome homeostasis maintenance for optimal general health preservation.

Does vitamin D deficiency influence the incidence and progression of knee osteoarthritis? - A literature review

OBJECTIVES

Vitamin D has been believed to have a bearing in the pathogenesis of knee osteoarthritis (OA). This study was done to search the literature and review the correlation between vitamin D levels in knee OA in the adult population and the outcome of vitamin D supplementation in knee OA.

METHODS

An exhaustive search of Pub Med and Cochrane library database was done with keywords vitamin D, knee and osteoarthritis for a period from Jan 2005 to December 2015. All Randomized Control Trials (RCT), Cohort, Case-control, cross-sectional studies were included in the present systematic review.

RESULTS

The search resulted in a total of 86 studies; out of which 11 studies were included in the current review. There were two Randomized Control Trial (RCT), one case-control, four cross-sectional and four cohort studies. These studies comprised of a total of 5137 participants (ranging from 46 to 1248) Our results suggested there was a moderate evidence of positive association in vitamin D deficiency (VDD) and progression of radiographic OA (ROA), as assessed by Kellgren and Lawrence (KL) grading. However, VDD was not associated with the incidence of ROA and MRI-detected change in focal cartilage defect. However, this study has a limited evidence for a positive correlation in VDD and the cartilage volume loss. There was also limited evidence showing no role of vitamin D therapy in reducing cartilage volume loss and knee pain in Knee OA.

CONCLUSION

The VDD is common and has been associated with knee OA, in an adult population. However, there is still inconsistent evidence regarding the prevention of incidence and progression of ROA after vitamin D therapy. There is a need for multicentric and well-conducted randomized studies with larger samples to conclude the positive effect of Vitamin D therapy.

Body Mass Index Mediates the Association between Dietary Fiber and Symptomatic Knee Osteoarthritis in the Osteoarthritis Initiative and the Framingham Osteoarthritis Study

Background

Dietary fiber reduces body weight and inflammation in clinical trials. It is unclear whether body mass index (BMI) and inflammation might explain the observed association between higher fiber intake and the lower risk of symptomatic knee osteoarthritis (SXKOA).

Objectives

We quantified the extent to which BMI and inflammation influenced the relation between dietary fiber and SXKOA.

Methods

We used longitudinal data from the Osteoarthritis Initiative (OAI) and the Framingham Offspring Osteoarthritis Study. At baseline of each study, men and women (mean age: 61 y) with or at risk of knee osteoarthritis were followed for 48 mo in the OAI. Adults (mean age: 53 y) were followed for 9.5 y in the Framingham study. Dietary fiber intake was estimated using a validated food-frequency questionnaire. Measured weight and height were used to calculate BMI. Serum high-sensitivity C-reactive protein (CRP) was measured in the Framingham study only. Incident SXKOA was defined as new onset of a combination of knee pain and radiographic osteoarthritis. We applied marginal structural models to quantify the mediation through BMI in the OAI and the sequential mediation through BMI and CRP in the Framingham study.

Results

Incident SXKOA occurred in 861 knees among 2876 persons in the OAI and in 143 knees among 971 persons in the Framingham study. In persons whose fiber intake was ≥21 g/d compared with those with intakes <21 g/d, the OR (95% CI) was 0.70 (0.53, 0.91) for the overall association with SXKOA and was 0.93 (0.92, 0.95) for the mediation via BMI (per kg/m2) in the OAI. In the Framingham study, the overall association was 0.57 (0.30, 1.09), the mediation through BMI (via BMI and the influence of BMI on CRP) was 0.94 (0.85, 1.02), and the mediation through CRP (per milligram per liter) was 0.99 (0.84, 1.19).

Conclusion

Our findings suggest that the inverse association of fiber intake and the risk of incident symptomatic knee osteoarthritis is partially mediated by BMI.

Update on the epidemiology, risk factors and disease outcomes of osteoarthritis

Osteoarthritis (OA) is the most frequent form of arthritis and a leading cause of pain and disability worldwide. OA can affect any synovial joint, although the hip, knee, hand, foot and spine are the most commonly affected sites. Knowledge about the occurrence and risk factors for OA is important to define the clinical and public health burden of the disease to understand mechanisms of disease occurrence and may also help to inform the development of population-wide prevention strategies. In this article, we review the occurrence and risk factors for OA and also consider patient-reported outcome measures that have been used for the assessment of the disease.

Association of Vitamin K Status Combined With Vitamin D Status and Lower-Extremity Function: A Prospective Analysis of Two Knee Osteoarthritis Cohorts

OBJECTIVE

Vitamins K and D are important for the function of vitamin K-dependent proteins in joint tissues. It is unclear whether these nutrients are mutually important to functional outcomes related to knee osteoarthritis (OA). We evaluated the association of vitamin K and D sufficiency with lower-extremity function in the Health, Aging and Body Composition knee OA substudy (Health ABC) and conducted a replication analysis in an independent cohort, the Osteoarthritis Initiative (OAI).

METHODS

In Health ABC (60% female, mean ± SD age 75 ± 3 years) baseline nutrient status was measured using circulating vitamin K and 25-hydroxyvitamin D (25[OH]D). Lower-extremity function was assessed using the Short Physical Performance Battery (SPPB) and usual 20-meter gait speed. In the OAI (58% female, mean ± SD age 61 ± 9 years), baseline nutrient intake was estimated by food frequency questionnaire. Lower-extremity function was assessed using usual 20-meter gait speed and chair stand completion time. Multivariate mixed models were used to evaluate the association of vitamin K and D status and intake with lower-extremity function over 4-5 years.

RESULTS

Health ABC participants with sufficient plasma vitamin K (≥1.0 nmoles/liter) and serum 25(OH)D (≥50 nmoles/liter) generally had better SPPB scores and faster usual gait speed over followup (P ≤ 0.002). In the OAI, sufficient vitamin K and vitamin D intake combined was associated with overall faster usual gait speed and chair stand completion time over followup (P ≤ 0.029).

CONCLUSION

Sufficient vitamin K status combined with sufficient vitamin D status was associated with better lower-extremity function in 2 knee OA cohorts. These findings merit confirmation in vitamin K and D co-supplementation trials.

Association between vitamin D concentrations and knee pain in patients with osteoarthritis

Objectives

Osteoarthritis (OA) and vitamin D deficiency are common health conditions in older people. Whether vitamin D concentration is associated with knee OA is controversial. In this study, we aimed to determine the association between serum concentrations of vitamin D and osteoarthritic knee pain.

Subjects and Methods

Vitamin D concentrations were measured with the 25 hydroxyvitamin D test in patients presenting with clinical symptoms of primary knee osteoarthritis. Osteoarthritis was graded on the Kellgren-Lawrence grading scale from anteroposterior and lateral radiographs. Height, weight, and body mass index (BMI) were recorded. Patients completed a 10-cm visual analogue scale (VAS) for indicating pain and the Western Ontario and McMaster Universities Arthritis Index (WOMAC). Vitamin D concentration was defined as severely deficient (<10 ng/mL), insufficient (10 to 19 ng/mL), or normal (20 to 50 ng/mL).

Results

Of 149 patients (133 women), the mean age was 63.6 years. Mean vitamin D concentration was 11.53 ng/mL, and 90% patients were vitamin D deficient. Mean WOMAC score was 57.2, and VAS pain score was 7.5. Kellgren-Lawrence grade was 2 for 10 patients, grade 3 for 61, and grade 4 for 88. Mean BMI was 33.4. Mean values of VAS, WOMAC, and BMI did not differ by vitamin D status.

Conclusion

Serum vitamin D concentration is not associated with knee pain in patients with osteoarthritis.

Do vitamin D levels affect the clinical prognoses of patients with knee osteoarthritis?

OBJECTIVE

Although vitamin D deficiency has been associated with osteoporosis, as well as fractures, in elderly men and women, the role of vitamin D deficiency in the pathogenesis of osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the effects of vitamin D deficiency on the functional status and disease prognosis of patients with knee osteoarthritis.

PATIENTS AND METHODS

Our study comprised 100 patients that met the American College of Rheumatology criteria for a diagnosis of knee osteoarthritis. Each patient underwent knee radiography, the results of which were graded according to Kellgren and Lawrence radiographic grading scale; those that met the diagnostic criteria were included in the study. The visual analog scale (VAS), Nottingham Health Profile (NHP), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Lequesne Knee Osteoarthritis Index were used to assess patients' pain, function and quality of life. Complete blood counts, sedimentation rates and serum C-reactive protein, rheumatoid factor, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, sodium, potassium, calcium, phosphorus, parathyroid and thyroid hormone levels were routinely recorded for each patient. Vitamin D levels were analyzed in winter (between November and February) using high performance liquid chromatography.

RESULTS

Patients were divided into two groups, Group 1 and Group 2, according to the presence or absence of vitamin D deficiency. The groups did not differ significantly in terms of age, disease duration, sex distribution, presence of osteoporosis or radiographic stage of knee osteoarthritis (p = 0.793, 0.092, 0.250, 0.835 and 0.257, respectively). However, the NHP pain, physical activity, fatigue, social isolation, and emotional reactions subsets, WOMAC pain and physical function subsets and total score, Lequesne knee osteoarthritis index, and patient/physician VAS scores were significantly higher in Group 1 than in Group 2 (p < 0.05).

CONCLUSIONS

Our study therefore suggests that vitamin D deficiency exacerbates pain, dysfunction and a poorer quality of life in patients with knee osteoarthritis. Further longer-term studies are needed to investigate the effects of vitamin D deficiency on OA-related symptoms.

Maintaining Vitamin D Sufficiency Is Associated with Improved Structural and Symptomatic Outcomes in Knee Osteoarthritis

BACKGROUND

The aim of this study was to describe whether maintaining sufficient serum vitamin D levels in people with knee osteoarthritis and baseline vitamin D insufficiency has an association with change in knee structures and symptoms over 2 years.

METHODS

Participants (n = 413, mean age 63.2 years) with symptomatic knee osteoarthritis and vitamin D insufficiency were enrolled in a clinical trial. In all, 340 participants (82.3%) completed the study, with 25-hydroxyvitamin D [25(OH)D] measurements at baseline and months 3 and 24. Participants were classified as consistently insufficient [serum 25(OH)D ≤50 nmol/L at months 3 and 24, n = 45], fluctuating [25(OH)D >50 nmol/L at either point, n = 68), and consistently sufficient [25(OH)D >50 nmol/L at months 3 and 24, n = 226] groups. Knee cartilage volume, cartilage defects, bone marrow lesions, and effusion-synovitis volume were assessed using MRI at baseline and month 24. Knee symptoms were assessed at baseline and months 3, 6, 12, and 24 using the Western Ontario and McMaster Universities Arthritis Index.

RESULTS

The consistently sufficient group had significantly less loss of tibial cartilage volume (β 2.1%; 95% confidence interval [CI], 0.3%, 3.9%), less increase in effusion-synovitis volume (β -2.5 mL; 95 CI%, -4.7, -0.2 mL), and less loss of Western Ontario and McMaster Universities Arthritis Index physical function (β -94.2; 95% CI, -183.8, -4.5) compared with the consistently insufficient group in multivariable analyses. In contrast, there were no significant differences in these outcomes between the fluctuating and consistently insufficient groups. Changes in cartilage defects, bone marrow lesions, and knee pain were similar between groups.

CONCLUSION

This post hoc analysis suggests beneficial effects of maintaining vitamin D sufficiency on cartilage loss, effusion-synovitis, and physical function in people with knee osteoarthritis.

The effect of vitamin D status on pain, lower limb strength and knee function during balance recovery in people with knee osteoarthritis: an exploratory study

The association between vitamin D and muscle function associated with balance recovery and falls in people with knee osteoarthritis is unclear. Those with vitamin D insufficiency demonstrated poorer knee function during balance recovery, greater pain and locomotor dysfunction. Vitamin D insufficiency may have an adverse effect on muscle power function.

PURPOSE

Low vitamin D status in people with knee osteoarthritis (OA) is often reported to be associated with increased pain and locomotor dysfunction. However, despite the growing evidence of the effect of vitamin D on the pathogenesis of knee OA, its role remains conflicting. Importantly, muscle function is important for knee joint health; however, the association between vitamin D levels and muscle function associated with balance recovery and falls is unclear. This study investigated the effect of circulating 25-hydroxyvitamin D (25 (OH) D) on pain, quadriceps strength, lower limb muscle mass and knee power function during balance recovery in people with knee OA.

METHODS

Twenty-four participants with clinical symptoms of knee OA (68.6 ± 6.2 years) participated in the study. Serum levels of 25 (OH) D were assessed and participants were classified as follows: vitamin D insufficiency ≤ 50 nmol/L and vitamin D sufficiency > 50 nmol/L. The groups were compared on knee function during balance recovery tasks, lower limb strength and muscle mass as well as perceived pain and function.

RESULTS

Seven patients (29.1%) were classified as vitamin D-insufficient. Vitamin D insufficiency was associated with reduced knee muscle function during the balance recovery task, increased pain (Western Ontario and McMasters University Osteoarthritis Index (WOMAC) subscore), dysfunction (WOMAC subscore) and total WOMAC score (p < 0.05).

CONCLUSION

People with knee OA with vitamin D insufficiency demonstrated poorer knee function during balance recovery, greater pain and locomotor dysfunction. Vitamin D insufficiency may have an adverse effect on muscle power function.

The effect of vitamin D supplementation on knee osteoarthritis: A meta-analysis of randomized controlled trials

OBJECTIVE

We conducted a meta-analysis of RCTs to evaluate the effects of vitamin D supplementation in the prevention of symptom and structural progression of knee OA.

METHODS

PubMed, Embase, and Web of Science databases were searched to identify relevant studies. Outcomes included Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, function, stiffness, tibial cartilage volume, and serum vitamin D3 levels, and adverse events. Results were expressed as weight mean difference (WMD) with 95% confidence interval (CI), and risk ratio (RR) with 95%CI.

RESULTS

Four RCTs involving 1136 patients were included in this study. Pooled estimates suggested that vitamin D supplementation was associated with a significant reduction in WOMAC pain, and WOMAC function, but not in WOMAC stiffness. Vitamin D supplementation increased the serum vitamin D3 level, but had no effect on tibial cartilage volume. Subgroup analysis showed that, a daily supplement of more than 2000 IU vitamin D significantly decreased the WOMAC pain and WOMAC function. There was no significant difference in incidence of adverse events between the vitamin D and placebo groups.

CONCLUSION

Vitamin D supplementation was effective in improving the WOMAC pain and function in patients with knee OA. However, it had no beneficial effect on the prevention of tibial cartilage loss. Therefore, there is currently a lack of evidence to support the use of vitamin D supplementation in preventing the progression of knee OA.

Randomized trial of vitamin D3 to prevent worsening of musculoskeletal symptoms in women with breast cancer receiving adjuvant letrozole. The VITAL trial

PURPOSE

Aromatase inhibitor-associated musculoskeletal symptoms (AIMSS) frequently occur in women being treated for breast cancer. Prior studies suggest high prevalence of vitamin D deficiency in breast cancer patients with musculoskeletal (MS) pain. We conducted a randomized, placebo-controlled trial to determine if 30,000 IU vitamin D3 per week (VitD3) would prevent worsening of AIMSS in women starting adjuvant letrozole for breast cancer.

METHODS

Women with stage I-III breast cancer starting adjuvant letrozole and 25(OH)D level ≤40 ng/ml were eligible. All subjects received standard daily supplement of 1200 mg calcium and 600 IU vitamin D3 and were randomized to 30,000 IU oral VitD3/week or placebo. Pain, disability, fatigue, quality of life, 25(OH)D levels, and hand grip strength were assessed at baseline, 12, and 24 weeks. The primary endpoint was incidence of an AIMSS event.

RESULTS

Median age of the 160 subjects (80/arm) was 61. Median 25OHD (ng/ml) was 25 at baseline, 32 at 12 weeks, and 31 at 24 weeks in the placebo arm and 22, 53, and 57 in the VitD3 arm. There were no serious adverse events. At week 24, 51% of women assigned to placebo had a protocol defined AIMSS event (worsening of joint pain using a categorical pain intensity scale (CPIS), disability from joint pain using HAQ-II, or discontinuation of letrozole due to MS symptoms) vs. 37% of women assigned to VitD3 (p = 0.069). When the brief pain inventory (BPI) was used instead of CPIS, the difference was statistically significant: 56 vs. 39% (p = 0.024).

CONCLUSIONS

Although 30,000 IU/week of oral vitamin D3 is safe and effective in achieving adequate vitamin D levels, it was not associated with a decrease in AIMSS events based on the primary endpoint. Post-hoc analysis using a different tool suggests potential benefit of vitamin D3 in reducing AIMSS.

Dietary intake of fibre and risk of knee osteoarthritis in two US prospective cohorts

OBJECTIVES

Dietary fibre reduces body weight and inflammation both of which are linked with knee osteoarthritis (OA). We examined the association between fibre intake and risk of knee OA.

METHODS

We used data from the Osteoarthritis Initiative (OAI) of 4796 participants and Framingham Offspring Osteoarthritis Study (Framingham) of 1268 persons. Dietary intake of fibre was estimated at baseline, and incident radiographic OA (ROA) and symptomatic OA (SxOA) were followed annually until 48 months in OAI and assessed 9 years later in Framingham. Knee pain worsening was also examined in OAI. Generalised estimating equations were applied in multivariable regression models.

RESULTS

In OAI, we identified 869 knees with SxOA, 152 knees with ROA and 1964 knees with pain worsening among 4051 subjects with valid dietary intake (baseline mean age: 61.2 years; mean body mass index (BMI): 28.6). In Framingham, 143 knees with SxOA and 176 knees with ROA among 971 such subjects (baseline mean age: 53.9 years; mean BMI: 27.0) were identified. In both cohorts, dietary total fibre was inversely associated with risk of SxOA (p trend <0.03) with significantly lower risk at the highest versus lowest quartile (OR (95% CI): 0.70 (0.52, 0.94) for OAI and 0.39 (0.17, 0.88) for Framingham). Furthermore, dietary total and cereal fibre were significantly inversely associated with knee pain worsening in OAI (p trend <0.02). No apparent association was found with ROA.

CONCLUSIONS

Findings from two longitudinal studies consistently showed that higher total fibre intake was related to a lower risk of SxOA, while the relation to ROA was unclear.

Vitamin D supplementation for the management of knee osteoarthritis: a systematic review of randomized controlled trials

Conflicting evidence exists concerning the supplementation of vitamin D in knee osteoarthritis condition. This systematic literature review was done to explore the effects of vitamin D supplementation in the management of knee osteoarthritis. Electronic literature search was done in databases like PubMed^®, Embase^®, and Cochrane CENTRAL from inception to 6th July 2016. The quality of included Randomized Controlled Trials (RCTs) was assessed using Cochrane risk of bias tool. We considered change in Western Ontario and McMaster Universities (WOMAC) index, Visual Analog Scale (VAS) and Functional Pain Score (FPS) as the primary outcome measure. Change in tibial cartilage thickness, joint space width and safety profile was considered as secondary outcomes. Participants were randomized either to treatment or placebo group. Participants received cholecalciferol as an intervention through oral route in the dose range of 800-60,000 IU except in the one study where participants received ergocalciferol. All included RCTs showed a significant increase in serum vitamin D level in the treatment group compared to the placebo group at the end point. No significant reduction in pain and function was reported on WOMAC scale except in one study. No significant difference was reported for WOMAC stiffness in any study. VAS was assessed in three studies in which two showed statistically significant improvement in knee pain. Three of the RCTs reported safety data with one incidence of calculus ureteric and hip fracture found to be related to the drug. The study found evidence from RCTs to be insufficient to support the use of vitamin D supplementation for patients with knee osteoarthritis.

Effect of vitamin D levels on radiographic knee osteoarthritis and functional status

Objectives

This study aims to investigate the effect of serum levels of 25 hydroxyvitamin D (25(OH)D) in patients with primary knee osteoarthritis (OA) and to assess its relationship with the radiographic grading and functional status.

Patients and methods

Serum 25(OH)D levels were measured in 107 patients (90 females, 17 males; mean age 63.0±9.6 years; range, 40 to 86 years) with primary knee OA. Radiographic grading was based on the Kellgren-Lawrence Grading Scale and the Osteoarthritis Research Society International (OARSI) Atlas Grading Scale, while the functional status was assessed using the Lequesne indices and Turkish version of the Knee Injury and Osteoarthritis Outcome Score-Physical Function Short-Form (KOOS-PS). Pain was evaluated using the Visual Analog Scale for Pain (VAS-Pain). Data including age, sex, disease duration, body mass index (BMI), and pain severity were recorded.

Results

The mean 25(OH)D level was 13.4±10.6 ng/mL, and 90 patients (84.1%) had vitamin D deficiency. The presence of severe osteophytes was observed in 67 patients (62.6%) and 85 patients (79.4%) had Grade 2-3 joint space narrowing (JSN). The mean KOOS-PS and Lequesne scores were 40.1±12.3 and 12.9±3.6, respectively. There was no correlation between serum 25(OH)D levels and functional status.

Conclusion

Our study results show that serum 25(OH)D level is not related to the severity of the radiographic knee OA grading or to the functional assessment. Age and BMI are the factors affecting the radiological knee OA severity, while age, sex, BMI, and pain severity are the main determinants of the functional status.

Low Skeletal Muscle Mass in the Lower Limbs Is Independently Associated to Knee Osteoarthritis

Objectives

It has been reported that low skeletal muscle mass correlates with knee osteoarthritis in obese individuals. This study aimed to investigate whether lower limb skeletal muscle mass is independently associated with knee osteoarthritis in the general population.

Materials and Methods

This cross-sectional study used public data from the Fourth and Fifth Korean National Health and Nutrition Examination Survey. Subjects included 4924 community-dwelling adults aged ≥50 years (821 subjects with knee osteoarthritis and 4,103 controls). Skeletal muscle mass index (SMI) was calculated from the appendicular skeletal muscle mass measured by dual energy X-ray absorptiometry. Independent effects of total and lower limb SMI values on knee osteoarthritis were determined using odds ratios (OR) adjusted for age, sex, obesity, total femur bone mineral density, serum vitamin D level, diabetes mellitus status, and physical activity on multivariate logistic regression analysis.

Results

The adjusted logistic regression model revealed that older age, female sex, and obesity were significantly associated with knee osteoarthritis. A higher serum vitamin D level was also positively correlated with knee osteoarthritis (OR, 1.015; 95% CI, 1.003–1.027; P = 0.010). Although total SMI was not significantly associated with knee osteoarthritis (OR, 0.976; 95% CI, 0.946–1.007; P = 0.127), a low lower limb SMI had an independent effect on knee osteoarthritis (OR, 0.941; 95% CI, 0.900–0.983; P = 0.006).

Conclusions

Low skeletal muscle mass in the lower limbs but not in the whole body was independently associated with knee osteoarthritis.

The effect of vitamin D supplementation on knee osteoarthritis, the VIDEO study: a randomised controlled trial

OBJECTIVE

Epidemiological data suggest low serum 25-hydroxyvitamin D₃ (25-OH-D₃) levels are associated with radiological progression of knee osteoarthritis (OA). This study aimed to assess whether vitamin D supplementation can slow the rate of progression.

METHOD

A 3-year, double-blind, randomised, placebo-controlled trial of 474 patients aged over 50 with radiographically evident knee OA comparing 800 IU cholecalciferol daily with placebo. Primary outcome was difference in rate of medial joint space narrowing (JSN). Secondary outcomes included lateral JSN, Kellgren & Lawrence grade, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain, function, stiffness and the Get up and Go test.

RESULTS

Vitamin D supplementation increased 25-OH-D₃ from an average of 20.7 (standard deviation (SD) 8.9) μg/L to 30.4 (SD 7.7) μg/L, compared to 20.7 (SD 8.1) μg/L and 20.3 (SD 8.1) μg/L in the placebo group. There was no significant difference in the rate of JSN over 3 years in the medial compartment of the index knee between the treatment group (average -0.01 mm/year) and placebo group (-0.08 mm/year), average difference 0.08 mm/year (95% confidence interval (CI) [-0.14-0.29], P = 0.49). No significant interaction was found between baseline vitamin D levels and treatment effect. There were no significant differences for any of the secondary outcome measures.

CONCLUSION

Vitamin D supplementation did not slow the rate of JSN or lead to reduced pain, stiffness or functional loss over a 3-year period. On the basis of these findings we consider that vitamin D supplementation has no role in the management of knee OA.

Vitamin D attenuates inflammation, fatty infiltration, and cartilage loss in the knee of hyperlipidemic microswine

Background

Osteoarthritis (OA) of the knee joint is a degenerative process resulting in cartilage loss. Recent evidence suggests that OA is not merely a disease of cartilage but a disease of the entire knee joint and that inflammation may play an important role. OA has been associated with vitamin D deficiency. Vitamin D as an immunomodulator and anti-inflammatory agent may attenuate inflammation in the knee. The aim of this study was to assess the anti-inflammatory effect of vitamin D on inflammation in the knee.

Methods

This study was conducted with 13 microswine on a high cholesterol diet categorized into three groups of vitamin D-deficient, vitamin D-sufficient, and vitamin D supplementation. After 1 year, microswine were killed, and their knee joint tissues were harvested. Histological and immunofluorescence studies were carried out on the tissue specimens to evaluate the effect of vitamin D status.

Results

Histological and immunofluorescence studies of the knee joint tissues showed (1) increased inflammation in the knee joint tissues, (2) fatty infiltration in quadriceps muscle, patellar tendon, and collateral ligaments, and (3) chondrocyte clustering in the vitamin D-deficient and vitamin D-sufficient groups compared with the vitamin D supplementation group. Architectural distortion of the quadriceps muscle, patellar tendon, and collateral ligaments was also seen in the areas of inflammatory foci and fatty infiltration in the vitamin D-deficient group.

Conclusions

Decreased inflammation and fatty infiltration in the vitamin D supplementation group suggest the potential role of vitamin D in attenuating inflammation and fatty infiltration as well as in protecting the architecture of the tissue in the knee joint.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1099-6) contains supplementary material, which is available to authorized users.

24R,25-Dihydroxyvitamin D3 Protects against Articular Cartilage Damage following Anterior Cruciate Ligament Transection in Male Rats

Osteoarthritis (OA) in humans is associated with low circulating 25-hydroxyvitamin D3 [25(OH)D3]. In vitamin D replete rats, radiolabeled 24R,25-dihydroxyvitamin D3 [24R,25(OH)2D3] accumulates in articular cartilage following injection of [3H]-25(OH)D3. Previously, we showed that 24R,25(OH)2D3 blocks chondrocyte apoptosis via phospholipase D and p53, suggesting a role for 24R,25(OH)2D3 in maintaining cartilage health. We examined the ability of 24R,25(OH)2D3 to prevent degenerative changes in articular cartilage in an OA-like environment and the potential mechanisms involved. In vitro, rat articular chondrocytes were treated with IL-1β with and without 24R,25(OH)2D3 or 1α,25(OH)2D3. 24R,25(OH)2D3 but not 1α,25(OH)2D3 blocked the effects of IL-1β in a dose-dependent manner, and its effect was partially mediated through the TGF-β1 signaling pathway. In vivo, unilateral anterior cruciate ligament transections were performed in immunocompetent rats followed by intra-articular injections of 24R,25(OH)2D3 or vehicle (t = 0, 7, 14, 21 days). Tissues were harvested on day 28. Joints treated with vehicle had changes typical of OA whereas joints treated with 24R,25(OH)2D3 had less articular cartilage damage and levels of inflammatory mediators. These results indicate that 24R,25(OH)2D3 protects against OA, and suggest that it may be a therapeutic approach for preventing trauma-induced osteoarthritis.

Diet-Intestinal Microbiota Axis in Osteoarthritis: A Possible Role

Intestinal microbiota is highly involved in host physiology and pathology through activity of the microbiome and its metabolic products. Osteoarthritis (OA) is a common form of arthritis characterized by articular cartilage destruction and osteophyte formation. Although various person-level risk factors, such as age, sex, and obesity, have been proposed for the pathogenesis of OA, the underlying links between these person-level factors and OA are still enigmatic. Based on the current understanding in the crosstalk between intestinal microbiota and these risk factors, intestinal microbiota could be considered as a major hidden risk factor that provides a unifying mechanism to explain the involvement of these person-level risk factors in OA.

Low Levels of Vitamin D have a Deleterious Effect on the Articular Cartilage in a Rat Model

BACKGROUND

Vitamin D appears to play an important role in bone and cartilage metabolism since its receptors are widely found in human articular chondrocytes. Thus, effects of variation of vitamin D may directly impact cartilage and bone biology.

QUESTIONS/PURPOSES

The aims of this study are to compare (1) articular cartilage structure and composition and (2) trabecular and cortical bone microstructure in rats with normal versus insufficient vitamin D levels.

METHODS

Twenty-five mature, male Sprague-Dawley rats were allocated to two groups: (1) control arm (vitamin D replete-12 rats) and (2) an experimental arm (vitamin D deficient-13 rats). Vitamin D deficiency was induced using a vitamin D-deficient diet and UV light restriction. Rats were sacrificed after 4 weeks vitamin D deficiency was confirmed. The right knee was harvested for analysis of both the medial (MFC) and lateral femoral condyles (LFC). A region of interest was established on both condyles to correlate subchondral bone architecture and the overlying cartilage. Histological analysis was performed and graded using the modified Mankin score. Subchondral and cortical bony architecture was evaluated with micro-CT.

RESULTS

After 4 weeks, the vitamin D-deficient group had statistically significant changes in cartilage structure in both the MFC and LFC [1.55 ± 0.6 vs. 4.23 ± 4.1 (p = 0.035) and 1.55 ± 0.6 vs. 3.53 ± 2.4 (p = 0.009), respectively]. Micro-CT analysis revealed no correlation between subchondral bone values and the overlying cartilage Mankin score (p = 0.460). No significant difference was evident between the subchondral bone of the control and study group.

CONCLUSIONS

Low levels of vitamin D have a deleterious effect on the cartilage. Given the high prevalence of vitamin D deficiency in the general population, these findings raise important questions about the potential role of vitamin D in articular cartilage health.

Characterization of osteoarthritic human knees indicates potential sex differences

BACKGROUND

The prevalence of osteoarthritis is higher in women than in men in every age group, and overall prevalence increases with advancing age. Sex-specific differences in the properties of osteoarthritic joint tissues may permit the development of sex-specific therapies. Sex hormones regulate cartilage and bone development and homeostasis in a sex-dependent manner. Recent in vitro studies show that the vitamin D3 metabolite 1α,25-dihydroxyvitamin D3 [1α,25(OH)2D3] also has sex-specific effects on musculoskeletal cells, suggesting that vitamin D3 metabolites may play a role in osteoarthritis-related sex-specific differences. The purpose of this study was to determine if sex-specific differences exist in synovial fluid and knee tissues isolated from male and female patients with severe knee osteoarthritis. We determined the presence of vitamin D3 metabolites, inflammatory cytokines, growth factors, and matrix metalloproteinases (MMPs) in synovial fluid and assessed responses of articular chondrocytes and subchondral osteoblasts to 17β-estradiol, dihydrotestosterone, and 1α,25(OH)2D3.

METHODS

Samples from knee joints of 10 Caucasian male and 10 Caucasian female patients with advanced osteoarthritis aged 65 to 75 years were obtained from total knee arthroplasty. Vitamin D metabolites, cytokines, MMPs, and growth factors in the synovial fluid were measured. Primary cultures of chondrocytes were isolated from fibrillated articular cartilage adjacent to osteoarthritis lesions and minimally affected cartilage distal to the lesion. Osteoblasts were isolated from the subchondral bone. Expression of receptors for 17β-estradiol and 1α,25(OH)2D3 was assessed by real-time PCR. Chondrocytes and osteoblasts were treated with 10(-8) M 17β-estradiol, dihydrotestosterone, or 1α,25(OH)2D3 and effects on gene expression and protein synthesis determined.

RESULTS

Histology of the articular cartilage confirmed advanced osteoarthritis. Sex differences were found in synovial fluid levels of vitamin D metabolites, cytokines, and metalloproteinases as well as in the cellular expression of receptors for 17β-estradiol and 1α,25(OH)2D3. Male cells were more responsive to 1α,25(OH)2D3 and dihydrotestosterone, whereas 17β-estradiol-affected female cells.

CONCLUSIONS

These results demonstrate that there are underlying sex differences in knee tissues affected by osteoarthritis. Our findings do not address osteoarthritis etiology but have implications for different prevention methods and treatments for men and women. Further research is needed to better understand these sex-based differences.