The impact of obesity on the development and progression of rheumatoid arthritis

A stronger association of depression with rheumatoid arthritis in presence of obesity and hypertriglyceridemia

Background

Rheumatoid arthritis (RA) is an autoimmune disorder characterized by chronic and systemic inflammation. Recent research underscores the role of chronic inflammation in multiple common RA comorbidities such as depression, obesity, and cardiovascular diseases (CVDs), suggesting a potential overlap of the pathogenic mechanisms for RA. However, it is not well understood how the coexistence of these comorbid conditions impacts the risk of RA and whether any such association relates to body's inflammatory state.

Methods

We used data from the 2007-2010 United States National Health and Nutrition Examination Survey (NHANES) database and compared RA prevalence between subsamples with the presence of any two conditions among depression, obesity, and hypertriglyceridemia (HTG). Each subsample was further divided into three categories based on the serum level of the inflammatory marker C-reactive protein (CRP) and analyzed for statistically significant differences using three-way χ2 tests of independence.

Results

The study was conducted on 4,136 patients who fulfilled the inclusion criteria (representing 163,540,241 individuals after adjustment for sampling weights). Rates of depression, obesity, and HTG were found to be significantly higher (P < 0.001) among the subjects with RA compared with the control population with no arthritis. The presence of depression along with obesity or HTG showed a noticeably higher RA prevalence but such an association was not observed for the combination of obesity and HTG. The synergistic effect of HTG with depression was found to be most prominent at a medium CRP level (1-3 mg/L), while for obesity, the effect was observed across all CRP levels examined. These findings were further confirmed by the three-way χ2 test for independence.

Conclusions

The presence of obesity or HTG in subjects suffering from depression might pose an increased risk of RA. Inflammatory mechanisms potentially play an important underlying role as suggested by the strong dependency of the association to CRP level. Identification of synergistic associations between RA risk conditions could provide useful information to predict the development and progress of RA.

Lower Frequency of Comorbidities Prior to Onset of Giant Cell Arteritis: A Population-Based Study

OBJECTIVE

To assess the frequency of comorbidities and metabolic risk factors at and prior to giant cell arteritis (GCA) diagnosis.

METHODS

This is a retrospective case control study of patients with incident GCA between January 1, 2000, and December 31, 2019, in Olmsted County, Minnesota. Two age- and sex-matched controls were identified, and each assigned an index date corresponding to an incidence date of GCA. Medical records were manually abstracted for comorbidities and laboratory data at incidence date, 5 years, and 10 years prior to incidence date. Twenty-five chronic conditions using International Classification of Diseases, 9th revision, diagnosis codes were also studied at incidence date and 5 years prior to incidence date.

RESULTS

One hundred and twenty-nine patients with GCA (74% female) and 253 controls were identified. At incidence date, the prevalence of diabetes mellitus (DM) was lower among patients with GCA (5% vs 17%; P = 0.001). At 5 years prior to incidence date, patients were less likely to have DM (2% vs 13%; P < 0.001) and hypertension (27% vs 45%; P = 0.002) and had a lower mean number (SD) of comorbidities (0.7 [1.0] vs 1.3 [1.4]; P < 0.001) compared to controls. Moreover, patients had significantly lower median fasting blood glucose (FBG; 96 mg/dL vs 104 mg/dL; P < 0.001) and BMI (25.8 vs 27.7; P = 0.02) compared to controls. Multivariable logistic regression analysis revealed negative associations for FBG with GCA at 5 and 10 years prior to diagnosis/index date.

CONCLUSION

DM prevalence and median FBG and BMI were lower in patients with GCA up to 5 years prior to diagnosis, suggesting that metabolic factors influence the risk of GCA.

Prevalence and characteristics of diffuse idiopathic skeletal hyperostosis (DISH) in Italy

Purpose

Diffuse idiopathic skeletal hyperostosis (DISH) is a benign condition characterized by ossification of the spine and prominent enthesopathies. Highly heterogeneous epidemiological figures have been reported in the literature, while in Italy the largest study has been conducted in 1992. The aim of our research is to contribute updated information about prevalence of DISH in Italy and to describe the clinical and radiographic characteristics associated with the disorder.

Material and methods

A retrospective review of lumbosacral spine, thoracic spine and pelvis radiographs was performed. Consecutive patients visiting the emergency department of our Institution over 3 years were enrolled. Presence of DISH was evaluated applying the Resnick and Niwayama criteria. Clinical and radiological features were also assessed.

Results

We included 1012 individuals (60.6% women), and DISH was present in 130 cases. The overall prevalence of DISH was 12.8% (95% CI 10.8–15.1), with higher figures in the male sample (16.8%) than in females (10.3%). In binary logistic regression adjusted for age, BMI (OR 1.50, p < 0.001) diabetes (OR 1.85, p = 0.003), hypertension (OR 2.04, p = 0.007) ischiopubic enthesopathy (OR 7.08, p < 0.001), iliac crest enthesopathy (OR 4.63, p < 0.001) and greater trochanter enthesopathy (OR 3.51, p < 0.001), were significantly associated with the condition.

Conclusion

The prevalence of DISH observed in our study is consistent with previous literature, and we confirm that the disorder is more frequently retrieved in men and that it is associated with the presence of metabolic disorders and pelvic enthesopathy. Knowledge about the epidemiology and characteristics of DISH is needed to properly identify the condition.

Glycolysis aggravates methotrexate toxicity by fueling RFC1-controlled intestinal absorption in rheumatic rats

Methotrexate (MTX) is a first line anti-rheumatic drug. This study was designed to investigate the impact of rheumatoid arthritis (RA) conditions on its oral absorption, and clarify the relevance with changes of MTX absorption-related transporters in rheumatic models. MTX was orally administered to healthy, collagen-induced arthritis (CIA), and adjuvant-induced arthritis (AIA) rats. MTX plasma concentrations were determined by a validated liquid chromatography-mass spectrometry method. We found that intestinal MTX absorption was significantly increased in CIA/AIA rats versus healthy controls. This finding was supported by small intestine-based MTX uptake assay in vitro. Meanwhile, intestinal expression of both reduced folate carrier 1 (RCF1) and proton-coupled folate transporter (PCFT) remained unchanged. The everted intestinal sac assay confirms RFC1 is the key transporter accounting for intestinal MTX absorption, as its antagonist salicylazosulfapyridine showed potent capacity in reducing MTX uptake. No correlation between RA-related cytokines and RCF1 expression was observed in clinical samples. We further revealed that when cultured with AIA rat or RA patient serum, lactate and adenosine triphosphate (ATP) production as well as MTX uptake in MDCKII cells were significantly increased, and this increase was completely abrogated by ATP production-related metabolic inhibitors. Thanks to its inhibitory effects on MTX bioavailability, the glycolysis inhibitor shikonin diminished MTX-induced injuries of kidney and liver in AIA rats. These data demonstrate that glycolysis-driven high energy metabolism increases MTX absorption in rheumatic subjects, leading to the exacerbated toxicity. These findings will have important implications in optimizing MTX regimens for RA treatment with better efficacy and lower toxicity.

[Rehabilitation in Rheumatoid Arthritis]

Die rheumatoide Arthritis stellt unter den Erkrankungen des Bewegungssystems eine besondere Herausforderung für die Rehabilitationsmedizin dar 1. Eine genaue Kenntnis der Erkrankung, inklusive der medikamentösen und der nicht medikamentösen Behandlungsoptionen, ist die wesentliche Voraussetzung für einen nachhaltigen Rehabilitationserfolg und um den berechtigen Anspruch der Erkrankten auf berufliche und soziale Partizipation umzusetzen.

Comparison of Psoriatic Arthritis and Rheumatoid Arthritis Patients across Body Mass Index Categories in Switzerland

Abnormal body mass index (BMI) was associated with worse rheumatic markers in psoriatic arthritis (PsA) and rheumatoid arthritis (RA). Aiming to describe PsA and RA patients stratified by BMI, we performed a descriptive study in PsA and RA patients (two distinct cohorts) in the Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) registry. New users of biologic or targeted synthetic disease-modifying anti-rheumatic drugs (b/tsDMARDs) were stratified by BMI at the start of their treatment (underweight, normal weight, overweight, obese). The PsA underweight and normal weight categories were merged. Age at disease onset and further characteristics at the start of the first b/tsDMARD treatment were compared across BMI categories vs. the corresponding normal weight group. The study included 819 PsA (36.5% overweight, 23.8% obese) and 3217 RA patients (4.4% underweight, 31.8% overweight, 17.0% obese). Compared to the corresponding normal weight group, PsA and RA obese patients had significantly (p < 0.05) higher C-reactive protein, worse disease activity, and lower quality of life (QoL). Obese PsA patients had significantly worse skin manifestation and pain, while obese RA patients had significantly higher erythrocyte sedimentation rate and tender joint counts, as well as lower seropositive prevalence. To conclude, obese PsA and RA patients presented worse disease activity and poorer QoL than those with normal weight.

Serum IL-35 is decreased in overweight patients with rheumatoid arthritis: its correlation with Th1/Th2/Th17-related cytokines

Background

Obesity is correlated with worse drug responses and high disease activity in patients with rheumatoid arthritis (RA). Interleukin (IL)-35 is a novel anti-inflammatory cytokine that mainly produced by regulatory T (Treg). This study was performed to analyze whether IL-35 was correlated with obesity in RA and investigate the correlation between other Th1/Th2/Th17-related cytokines and obesity in RA.

Results

The serum IL-35 level was analyzed in RA (n = 81) and healthy donors (n = 53) by ELISA assay, and was compared between three groups (body mass index (BMI) < 18.5,≥18.5 to 25, > 25). Serum cytokines including IL-2, IL-4, IL-10, IL-17, INF-γ, TNF-α levels were measured using Flowcytometry assay. Clinical information was extracted from medical records. Serum IL-35 level in overweight patients were significantly decreased than those in lean patients. Furthermore, Th1/Th2/Th17-related cytokines from overweight patients with RA showed the characteristic immunological features. Serum IL-6, IL-17 and TNF-α levels were positively correlated with BMI. However, serum IL-2, IL-4, IL-10 and IFN-γ concentrations were not correlated with BMI.

Conclusions

Quantitative changes in serum IL-35 level were characteristic in overweight patients with RA. These findings indicate that IL-35 plays an important role in the development of RA and may prove to be a potential biomarker of active RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12865-021-00431-x.

Geographic Variation in the Prevalence of Rheumatoid Arthritis in Alberta, Canada

OBJECTIVES

Timely access to rheumatologists remains a challenge in Alberta, a Canadian province with vast rural areas, whereas rheumatologists are primarily clustered in metro areas. To address the goal of timely and equitable access to rheumatoid arthritis (RA) care, health planners require information at the regional and local level to determine the RA prevalence and the associated health care needs.

METHODS

Using Alberta Health administrative databases, we identified RA-prevalent cases (April 1, 2015-March 31, 2016) on the basis of a validated case definition. Age- and sex-standardized prevalence rates per 1000 population members and the standardized rates ratio (SRR) were calculated. We applied Global Moran's I and Gi* hotspot analysis using three different weight matrices to explore the geospatial pattern of RA prevalence in Alberta.

RESULTS

Among 38 350 RA cases (68% female; n = 26 236), the prevalence rate was 11.81 cases per 1000 population members (95% confidence interval [CI] 11.80-11.81) after age and sex standardization. Approximately 60% of RA cases resided in metro (Calgary and Edmonton) and moderate metro areas. The highest rate was observed in rural areas (14.46; 95% CI 14.45-14.47; SRR 1.28), compared with the lowest in metro areas (10.69; 95% CI 10.68-10.69; SRR 0.82). The RA prevalence across local geographic areas ranged from 4.7 to 30.6 cases. The Global Moran's I index was 0.15 using three different matrices (z-score 3.96-4.24). We identified 10 hotspots in the south and north rural areas and 18 cold spots in metro and moderate metro Calgary.

CONCLUSION

The findings highlight notable rural-urban variation in RA prevalence in Alberta. Our findings can inform strategies aimed at reducing geographic disparities by targeting areas with high health care needs.

Cardiovascular Risk in Rheumatoid Arthritis and Mechanistic Links: From Pathophysiology to Treatment

Rheumatoid arthritis (RA) is an autoimmune inflammatory arthritis. Inflammation, however, can spread beyond the joints to involve other organs. During the past few years, it has been well recognized that RA associates with increased risk for cardiovascular (CV) disease (CVD) compared with the general population. This seems to be due not only to the increased occurrence in RA of classical CVD risk factors and comorbidities like smoking, obesity, hypertension, diabetes, metabolic syndrome, and others but also to the inflammatory burden that RA itself carries. This is not unexpected given the strong links between inflammation and atherosclerosis and CVD. It has been shown that inflammatory cytokines which are present in abundance in RA play a significant role in every step of plaque formation and rupture. Most of the therapeutic regimes used in RA treatment seem to offer significant benefits to that end. However, more studies are needed to clarify the effect of these drugs on various parameters, including the lipid profile. Of note, although pharmacological intervention significantly helps reduce the inflammatory burden and therefore the CVD risk, control of the so-called classical risk factors is equally important. Herein, we review the current evidence for the underlying pathogenic mechanisms linking inflammation with CVD in the context of RA and reflect on the possible impact of treatments used in RA.

Treatment patterns and achievement of the treat-to-target goals in a real-life rheumatoid arthritis patient cohort: data from 1317 patients

Background

Data regarding the real-life predictors of low disease activity (LDA) in rheumatoid arthritis (RA) patients are limited. Our aim was to evaluate the rate and predictors of LDA and treatment patterns in RA.

Methods

This was a multicenter, prospective, RA cohort study where patients were evaluated in two different time points approximately 12 months apart. Statistical analysis was performed in order to identify predictors of LDA while patterns of disease-modifying anti-rheumatic drug [DMARDs; conventional synthetic (csDMARD) or biologic (bDMARD)] and glucocorticoid (GC) use were also recorded.

Results

The total number of patients included was 1317 (79% females, mean age: 62.9 years, mean disease duration: 10.3 years). After 1 year, 57% had achieved LDA (DAS28ESR<3.2) while 43% did not (34%: moderate disease activity: DAS28ESR ⩾3.2 to <5.1, 9%: high disease activity, DAS28ESR ⩾5.1). By multivariate analysis, male sex was positively associated with LDA [odds ratio (OR) = 2.29 p < 0.001] whereas advanced age (OR = 0.98, p = 0.005), high Health Assessment Questionnaire (HAQ) score (OR = 0.57, p < 0.001), use of GCs (OR = 0.75, p = 0.037) or ⩾2 bDMARDs (OR = 0.61, p = 0.002), high co-morbidity index (OR = 0.86, p = 0.011) and obesity (OR = 0.62, p = 0.002) were negative predictors of LDA. During follow-up, among active patients (DAS28ESR >3.2), 21% initiated (among csDMARDs users) and 22% switched (among bDMARDs users) their bDMARDs.

Conclusion

In a real-life RA cohort, during 1 year of follow-up, 43% of patients do not reach treatment targets while only ~20% of those with active RA started or switched their bDMARDs. Male sex, younger age, lower HAQ, body mass index and co-morbidity index were independent factors associated with LDA while use of GCs or ⩾2 bDMARDs were negative predictors.

Adiposity and the risk of rheumatoid arthritis: a systematic review and meta-analysis of cohort studies

Several studies have investigated associations between overweight/obesity and risk of developing rheumatoid arthritis, however, the evidence is not entirely consistent, and previous meta-analyses mainly included case–control studies, which can be affected by various biases. We therefore conducted a systematic review and meta-analysis of cohort studies on adiposity and risk of rheumatoid arthritis. Relevant studies were identified by searching PubMed and Embase databases. Random effects models were used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs) for rheumatoid arthritis in relation to different measures of adiposity. Thirteen cohort studies (10 publications) were included. The summary RR per 5 kg/m² increase in body mass index (BMI) was 1.11 (95% CI 1.05–1.18, I² = 50%), but the association was restricted to women (1.15, 95% CI 1.08–1.21, I² = 17%) and not observed in men (0.89, 95% CI 0.73–1.09, I² = 58%). The summary RR per 5 kg/m² increment in BMI at age 18 years was 1.17 (95% CI 1.01–1.36, I² = 26%, n = 3), and per 10 cm increase in waist circumference was 1.13 (95% CI 1.02–1.25, I² = 44%, n = 2). Higher BMI in middle age, BMI at age 18 years, and waist circumference were associated with increased rheumatoid arthritis risk, suggesting adiposity could be targeted for primary prevention.

Adipokines and periodontal markers as risk indicators of early rheumatoid arthritis: a cross-sectional study

OBJECTIVE

To establish the association between adipokine levels and markers of periodontal involvement as risk indicators of early stages of RA (eRA) and the interaction between the presence of markers of periodontal disease with adipokine in eRA individuals.

MATERIALS AND METHODS

Fifty-one patients with a diagnosis of eRA and 51 healthy controls matched for age and sex were studied. Clinical joint condition, clinical and serological markers of disease activity, serum adipokine levels (leptin, adiponectin, resistin, adipsin, vaspin, and IL-6), periodontal diagnosis, presence of Porphyromonas gingivalis, and related IgG1 and IgG2 antibodies were evaluated. Comparisons were made between eRA and healthy controls for periodontal indicators and adipokines. A subgroup analysis was realized with a non-conditional logistic regression to establish the association between the levels of leptin in individuals with eRA and controls according to the periodontal condition, presence of P. gingivalis, or high titers of IgG antibodies against P. gingivalis.

RESULTS

The condition of overweight or obesity is associated with the diagnosis of eRA (p = 0.05), and these individuals also have higher levels of leptin (p = 0.001) and vaspin (p = 0.007). Higher frequency of P. gingivalis (p = 0.001) was found in the eRa group. Individuals with eRA with higher IgG2 titers against P. gingivalis had higher levels of leptin (OR: 1.66 (CI 95% 1.01-2.73)); however, individuals with periodontitis or P. gingivalis with eRA were associated with highest levels of leptin (OR: 1.86, CI 95% 1.19-24.3; and OR: 2.04, CI 95% 1.37-3 respectively).

CONCLUSIONS

eRA individuals have high levels of leptin and vaspin. However, the presence of periodontitis and related-periodontal disease markers showed an effect only in leptin levels in eRA individuals.

CLINICAL RELEVANCE

Emphasizing in personalized medicine, monitoring serum leptin levels and periodontitis markers can improve the early diagnosis of RA.

Body Mass Index Impact on Disease Activity, Clinical and Sonographic Remission Rates in Patients with Rheumatoid Arthritis

AIM

To investigate the impact of body mass index (BMI) on clinical disease activity indices and clinical and sonographic remission rates in patients with rheumatoid arthritis (RA).

PATIENTS AND METHODS

Sixty-three patients with RA were categorized according to BMI score into three groups: normal (BMI<25), overweight (BMI 25-30) and obese (BMI≥30). Thirty-three of them were treated with conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs), and 30 with biologic DMARDs (bDMARDs). Patients underwent clinical and laboratory assessment and musculoskeletal ultrasound examination (MSUS) at baseline and at 6 months after initiation of therapy. We evaluated the rate of clinical and sonographic remission (defined as Power Doppler score (PD) = 0) and its correlation with BMI score.

RESULTS

In the csDMARDs group, 60% of the normal weight patients reached DAS28 remission; 33.3% of the overweight; and 0% of the obese patients. In the bDMARDs group, the percentage of remission was as follows: 60% in the normal weight subgroup, 33.3% in the overweight; and 15.8% in the obese. Within the csDMARDs treatment group, two significant correlations were found: BMI score-DAS 28 at 6th month, rs = .372, p = .033; BMI score-DAS 28 categories, rs = .447, p = .014. Within the bDMARDs group, three significant correlations were identified: BMI score-PDUS at sixth month, rs = .506, p =.004; BMI score-DAS 28, rs = .511, p = .004; BMI score-DAS 28 categories, rs = .592, p = .001. Sonographic remission rates at 6 months were significantly higher in the normal BMI category in both treatment groups.

CONCLUSION

BMI influences the treatment response, clinical disease activity indices and the rates of clinical and sonographic remission in patients with RA. Obesity and overweight are associated with lower remission rates regardless of the type of treatment.

Depression as a risk factor for the development of rheumatoid arthritis: a population-based cohort study

Objectives

Major depressive disorder (MDD) is associated with increased levels of systemic proinflammatory cytokines, including tumour necrosis factor alpha. As these cytokines are pathogenic in autoimmune diseases such as rheumatoid arthritis (RA), our aim was to explore on a population-level whether MDD increases the risk of developing RA.

Methods

A retrospective cohort study was conducted using The Health Improvement Network (THIN) database (from 1986 to 2012). Observation time was recorded for both the MDD and referent cohorts until patients developed RA or were censored. Cox proportional hazards models were used to determine the risk of developing RA among patients with MDD, accounting for age, sex, medical comorbidities, smoking, body mass index and antidepressant use.

Results

A cohort of 403 932 patients with MDD and a referent cohort of 5 339 399 patients without MDD were identified in THIN. Cox proportional hazards models revealed a 31% increased risk of developing RA among those with MDD in an unadjusted model (HR=1.31, 95% CI 1.25 to 1.36, p<0.0001). When adjusting for all covariates, the risk remained significantly increased among those with MDD (HR=1.38, 95% CI 1.31 to 1.46, p<0.0001). Antidepressant use demonstrated a confounding effect that was protective on the association between MDD and RA.

Conclusion

MDD increased the risk of developing RA by 38%, and antidepressants may decrease this risk in these patients. Future research is necessary to confirm the underlying mechanism of MDD on the pathogenesis of RA.

The association of obesity with disease activity, functional ability and quality of life in early rheumatoid arthritis: data from the Early Rheumatoid Arthritis Study/Early Rheumatoid Arthritis Network UK prospective cohorts

OBJECTIVES

To examine associations between BMI and disease activity, functional ability and quality of life in RA.

METHODS

Data from two consecutive, similarly designed UK multicentre RA inception cohorts were used: the Early RA Study (ERAS) and the Early RA Network (ERAN). Recruitment figures/median follow-up for the ERAS and ERAN were 1465/10 years (maximum 25 years), and 1236/6 years (maximum 10 years), respectively. Standard demographic and clinical variables were recorded at baseline and annually. Multilevel piecewise longitudinal models with a change point at 2 years were used with the 28-joint DAS (DAS28), ESR, HAQ and 36-item Short Form Health Survey (SF-36) physical (PCS) and mental (MCS) components as dependent variables. BMI was examined in separate models as both continuous and categorical variables (based on World Health Organization definitions) and up to 5 years from disease onset.

RESULTS

BMI data from 2386 newly diagnosed RA patients (11 348 measures) showed an increase in BMI of 0.27 U annually (95% CI 0.21, 0.33). Baseline obesity was associated with a significant reduction in the odds of achieving a low year 2 DAS28 [OR 0.52 (95% CI 0.41, 0.650)]. At year 2, HAQ and SF-36 PCS scores were significantly worse but not at year 5 in patients obese at baseline. Obesity at year 2 was associated with higher DAS28 scores at year 2, but not at year 5, and also associated with significantly higher HAQ and SF-36 PCS scores at years 2 and 5.

CONCLUSION

Obesity prevalence is rising in early RA and associates with worse disease activity, function and health-related quality of life, with a significant negative impact on achieving a low DAS28. The data argue strongly for obesity management to become central to treatment strategies in RA.

Environmental factors and hormones in the development of rheumatoid arthritis

The etiopathogenesis of rheumatoid arthritis (RA) is partially understood. Genetic, environmental, and hormonal factors and their interactions are considered to play an important role on disease development. The relative contribution of environmental factors to RA development is probably larger than previously thought. The aim of this review is to appraise robust evidence about the role of environmental and hormonal risk factors for RA. We will discuss inhaled pollutants, nutritional habits, infectious, hormonal, and reproductive factors. As some of these factors are potentially modifiable, understanding their impact on RA development opens new opportunities for potential interventions and disease prevention.

Differential impact of obesity on the pathogenesis of RA or preclinical models is contingent on the disease status

OBJECTIVE

Studies were performed to uncover the significance of obesity in rheumatoid arthritis (RA) and preclinical models.

METHODS

Preclinical arthritis models were used to examine the impact of obesity on disease onset and remission. Conditioned media from RA adipose tissues were used to investigate the mechanism contributing to joint neutrophil influx and M1 macrophage differentiation observed in early and remission phases of arthritis.

RESULTS

We report that mice fed with high fat diet (HFD) have an earlier onset of collagen-induced arthritis (CIA) compared with mice on regular diet. However, the differences in CIA joint swelling between the two diet groups are lost once disease is established. We found that early arthritis triggered by obesity is due to elevated joint MIP2/interleukin-8 levels detected in CIA as well as in the RA and mouse adipose tissues and the effect of this chemokine on neutrophil recruitment. Although active disease progression is similarly affected in both diet groups, arthritis resolution is accelerated in lean mice while joint inflammation is sustained in obese mice. We document that HFD can prolong toll-like receptor (TLR)4-induced arthritis by increasing joint monocyte migration and further remodelling the recruited cells into M1 macrophages. Consistently, we show that adipose condition media can transform RA and wild-type naïve myeloid cells into M1 macrophages; however, this function is impaired by TLR4 blockade or deficiency.

CONCLUSIONS

We conclude that despite established disease being unaffected by obesity, the early and the resolution phases of RA are impacted by obesity through different mechanisms.

Are obesity, ACPAs and periodontitis conditions that influence the risk of developing rheumatoid arthritis in first-degree relatives?

The aim of this study was to investigate the body mass index (BMI), anti-citrullinated protein antibodies (ACPAs) status and the presence of periodontitis and IgG-1/IgG-2 antibodies against Porphyromonas gingivalis (Pg) in the first-degree relatives (FDRs) of rheumatoid arthritis (RA) patients and compare these variables with a control group of healthy individuals from the general population. In total, 100 FDR individuals and 200 healthy controls matched by age and gender were included. Rheumatologic and periodontal assessment was performed, and the presence of ACPAs and anti-P. gingivalis antibodies was evaluated. Groupwise comparisons were analysed using the McNemar and Wilcoxon tests. A conditional logistic regression analysis was performed to establish the associations between BMI, ACPAs and periodontitis in both groups. In the FDR group, 70% of the subjects were female, with a mean age of 37.3 ± 13 years. Obesity was observed in 17 and 7% of the FDRs and controls, respectively. ACPAs were found in 7% of the FDRs vs. 2.5% of the controls. Periodontitis was diagnosed in 79 and 56% of the FDRs and controls, respectively. Among the FDRs, 15% had severe periodontitis. There were associations in the FDR group related to the presence of obesity (OR 2.93, 95% CI 1.03-8.28), ACPAs (OR 2.45, 95% CI 0.7-8.32) and periodontitis (OR 3.70 95% CI 1.89-7.29). Regarding anti-P. gingivalis antibodies and smoking history, no differences were found between the groups. Obesity, ACPAs and periodontitis (diagnosis and severity) can be considered as relevant conditions associated with the development of RA in FDRs.

Body mass does not impact the clinical response to intravenous abatacept in patients with rheumatoid arthritis. Analysis from the "pan-European registry collaboration for abatacept (PANABA)

Some evidences suggest that obesity impairs the effectiveness of TNF inhibitors. We examined the impact of body mass index (BMI) on the clinical effectiveness of abatacept in rheumatoid arthritis (RA) patients. This is a pooled analysis of 10 prospective cohorts of RA patients. All patients with available BMI were included in this study. The primary endpoint was drug retention of abatacept in the different BMI categories. Multivariable Cox regression was used to estimate hazard ratios (HRs) for drug discontinuation. A secondary endpoint was EULAR/LUNDEX response rates at 6/12 months. Of the 2015 RA patients initiating therapy with IV abatacept, 380 (18.9%) were classified as obese. Obese patients had more functional disability, and were less often RF positive. The median abatacept retention time was 1.91 years for obese RA patients compared to 2.12 years for non-obese patients (p = 0.15). The risk of abatacept discontinuation was not significantly different for overweight (HR 1.03 (95% CI 0.89-1.19)), or for obese (HR 1.08 (95% CI 0.89-1.30)) compared to normal-weight patients. Rheumatoid factor positivity reduced the risk of abatacept discontinuation (HR 0.83 (95% CI 0.72-0.95)), while previous biologic therapy was positively associated with drug interruption (HRs increasing from 1.68 to 2.16 with the line of treatments). Obese and non-obese patients attained similar rates of EULAR/LUNDEX clinical response at 6/12 months. Drug retention and clinical response rates to abatacept do not seem to be decreased by obesity in RA patients.

Body mass index distribution in rheumatoid arthritis: a collaborative analysis from three large German rheumatoid arthritis databases

Background

METARTHROS (Metabolic impact on joint and bone disease) is a nationwide German network to investigate the overlap between inflammatory and metabolic diseases. The objective of this study was to compare the body mass index (BMI) distribution in patients with early and established rheumatoid arthritis (RA) with data from the general population, and to evaluate the association of BMI with patient characteristics and clinical markers.

Methods

The BMI distribution was examined with data collected at inclusion of patients in the early arthritis cohort CAPEA, the biologics register RABBIT, and the National database of the German Collaborative Arthritis Centers. A data source with a representative sample of the German population (German Ageing Survey) was used as a comparator. BMI categories of <18.5 kg/m² (underweight), 18.5 to <25 kg/m² (normal weight), 25 to <30 kg/m² (overweight), and ≥30 kg/m² (obese) were used. Patients were stratified by age and sex, and compared to controls from the German Ageing Survey. Associations between BMI and markers of disease activity were analysed with non-parametric tests and linear models.

Results

Data from 1207 (CAPEA), 12,230 (RABBIT), and 3424 (National database) RA patients and 6202 population controls were evaluated. The mean age was 56, 56, 62, and 62 years, respectively, the mean disease duration was 13 weeks, 9.9 years, and 13.5 years, respectively, and the mean disease activity score (DAS28) was 5.1, 5.2, and 3.1, respectively. In all RA cohorts, obesity was more frequent (23.8 %, 23.4 %, 21.4 %, respectively) than in controls (18.2 %). This applied to all age groups <70 years, was independent of disease duration, and was more pronounced in females. In all cohorts, the age at RA onset was associated with BMI, being higher in overweight/obese patients compared to normal-weight patients. Current smoking was negatively associated with BMI. Linear analyses revealed increased erythrocyte sedimentation rate (ESR) values in underweight and obese females, and an increasing disparity between tender joint counts (TJCs) and swollen joint counts (SJCs) in higher BMI categories.

Conclusions

Compared to the general population, a higher prevalence of obesity was observed in all RA cohorts. The dominance of obesity in females and the different behaviour of disease activity markers in relation to the BMI in females indicate that additional parameters need to be considered when analysing the impact of obesity on inflammation in RA.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-016-1043-9) contains supplementary material, which is available to authorized users.

High-fat diet exacerbates pain-like behaviors and periarticular bone loss in mice with CFA-induced knee arthritis

OBJECTIVE

Our aim was to quantify nociceptive spontaneous behaviors, knee edema, proinflammatory cytokines, bone density, and microarchitecture in high-fat diet (HFD)-fed mice with unilateral knee arthritis.

METHODS

ICR male mice were fed either standard diet (SD) or HFD starting at 3 weeks old. At 17 weeks, HFD and SD mice received intra-articular injections either with Complete Freund's Adjuvant (CFA) or saline into the right knee joint every 7 days for 4 weeks. Spontaneous pain-like behaviors and knee edema were assessed for 26 days. At day 26 post-first CFA injection, serum levels of IL-1β, IL-6, and RANKL were measured by ELISA, and microcomputed tomography analysis of knee joints was performed.

RESULTS

HFD-fed mice injected with CFA showed greater spontaneous pain-like behaviors of the affected extremity as well as a decrease in the weight-bearing index compared to SD-fed mice injected with CFA. Knee edema was not significantly different between diets. HFD significantly exacerbated arthritis-induced bone loss at the distal femoral metaphysis but had no effect on femoral diaphyseal cortical bone. HFD did not modify serum levels of proinflammatory cytokines.

CONCLUSIONS

HFD exacerbates pain-like behaviors and significantly increases the magnitude of periarticular trabecular bone loss in a murine model of unilateral arthritis.

Effects of intra-articular SHINBARO treatment on monosodium iodoacetate-induced osteoarthritis in rats

BACKGROUND

SHINBARO is a refined herbal formulation used to treat inflamed lesions and bone diseases. This study aimed to investigate the anti-osteoarthritic activities of intra-articular administration of SHINBARO and determine its underlying molecular mechanism in a monosodium iodoacetate (MIA)-induced osteoarthritis rat model.

METHODS

Male Sprague-Dawley rats received a single intra-articular injection of MIA into the infrapatellar ligament of the right knee. Subsequently, the rats were treated with normal saline, SHINBARO, and diclofenac once daily for 21 days. Rats treated with normal saline, but not MIA, comprised the control group. Histological changes in the femur of the MIA-induced osteoarthritis rat model were observed by micro-computed tomography scanning and staining with hematoxylin and eosin, and safranin-O fast green. Serum levels of PGE2 and anti-type II collagen antibodies in the MIA-induced osteoarthritis rat model were measured using commercial kits. Protein levels of inflammatory enzymes (iNOS, COX-2), pro-inflammatory cytokines (TNF-α, IL-1β), and inflammatory mediators (NF-κB, IκB) in cartilaginous tissues were determined by western blot analysis.

RESULTS

Intra-articular administration of SHINBARO (IAS) at 20 mg/kg remarkably restrained the decrease in bone volume/total volume, being 28 % (P = 0.0001) higher than that in the vehicle-treated MIA group. IAS (2, 10, and 20 mg/kg) treatment significantly recovered the mean number of objects values with increased percentage changes of 13.5 % (P = 0.147), 27.5 % (P = 0.028), and 44.5 % (P = 0.031), respectively, compared with the vehicle-treated MIA group. The serum level of PGE2 in the IAS group at 20 mg/kg was markedly inhibited by 60.6 % (P = 0.0007) compared with the vehicle-treated MIA group, and the anti-collagen type II antibody level in the IAS group was reduced in a dose-dependent manner. IAS (20 mg/kg) effectively suppressed the induction of inflammation-mediated enzymes (iNOS and COX-2) and pro-inflammatory cytokines (TNF-α and IL-1β). IAS treatment also downregulated the NF-κB level and increased the IκB-α level in the MIA- induced osteoarthritis rat model.

CONCLUSION

SHINBARO inhibited PGE2 and anti-type II collagen antibody production and modulated the balance of inflammatory enzymes, mediators, and cytokines in the MIA-induced osteoarthritis rat model.

Body Mass Index and Risk of Rheumatoid Arthritis: A Meta-Analysis of Observational Studies

Although many epidemiological studies have investigated the association between body mass index (BMI) and risk of rheumatoid (RA), the results have been inconsistent. Therefore, we performed a dose-response meta-analysis to quantify the dose-response association between BMI and RA risk.We systematically searched PubMed, Embase, and Web of Science databases and reference lists of articles for relevant studies published before August 2014 using terms related to BMI and RA. Fixed or random-effects models were used to estimate the pooled relative risk (RR) with 95% confidence interval (CI). Several subgroup analyses, sensitivity analyses, and publication bias tests were performed to explore potential study heterogeneity and biasThirteen studies involving 400,609 participants and 13,562 RA cases were included. The RR of RA was 1.21 (95% CI: 1.02-1.44) for obesity, 1.05 (95% CI: 0.97-1.13) for overweight. The risk of RA increased by 13% (RR: 1.13; 95% CI: 1.01-1.26) for every 5 kg/m increase in BMI. The subgroup analyses showed a positive association between BMI and RA risk only in women with an RR of 1.26 (95% CI: 1.12-1.40) for obesity and 1.12(95% CI: 1.07-1.18) for every 5 kg/m increase in BMI. Also, an increased risk of RA was found in sero-negative subgroup with an RR of 1.47 (95% CI: 1.11-1.96) for obesity and 1.21 (95% CI: 1.06-1.39) for every 5 kg/m increase in BMI.There is evidence that obesity is a risk factor for developing of RA. Furthermore, the positive association between BMI and RA risk may be stronger among women than men.

How does established rheumatoid arthritis develop, and are there possibilities for prevention?

Established rheumatoid arthritis (RA) is a chronic state with more or less joint damage and inflammation, which persists after a phase of early arthritis. Autoimmunity is the main determinant of persistence. Although the autoimmune response is already fully developed in the phase of early arthritis, targeted treatment within the first months produces better results than delayed treatment. Prevention of established RA currently depends on the success of remission-targeted treatment of early disease. Early recognition is aided by the new criteria for RA. Further improvement may be possible by even earlier recognition and treatment in the at-risk phase. This requires the improvement of prediction models and strategies, and more intervention studies. Such interventions should also be directed at modifiable risk factors such as smoking and obesity. The incidence of RA has declined for decades in parallel with the decrease of smoking rates; however, a recent increase has occurred that is associated with obesity.

Association between body composition and disease activity in rheumatoid arthritis. A systematic review

BACKGROUND

Reports regarding the association between body composition and inflammatory activity in rheumatoid arthritis (RA) have consistently yielded contradictory results.

OBJECTIVE

To perform a systematic review on the association between overweight/obesity and inflammatory activity in RA.

METHODS

FAST approach: Article search (Medline, EBSCO, Cochrane Library), followed by abstract retrieval, full text review and blinded assessment of methodological quality for final inclusion. Because of marked heterogeneity in statistical approach and RA activity assessment method, a meta-analysis could not be done. Results are presented as qualitative synthesis.

RESULTS

One hundred and nineteen reports were found, 16 of them qualified for full text review. Eleven studies (8,147 patients; n range: 37-5,161) approved the methodological quality filter and were finally included. Interobserver agreement for methodological quality score (ICC: 0.93; 95% CI: 0.82-0.98; P<.001) and inclusion/rejection decision (k 1.00, P>.001) was excellent. In all reports body composition was assessed by BMI; however a marked heterogeneity was found in the method used for RA activity assessment. A significant association between BMI and RA activity was found in 6 reports having larger mean sample size: 1,274 (range: 140-5,161). On the other hand, this association was not found in 5 studies having lower mean sample size: 100 (range: 7-150).

CONCLUSIONS

The modulation of RA clinical status by body fat mass is suggested because a significant association was found between BMI and inflammatory activity in those reports with a trend toward higher statistical power. The relationship between body composition and clinical activity in RA requires be approached with further studies with higher methodological quality.

High serum cholesterol predicts rheumatoid arthritis in women, but not in men: a prospective study

INTRODUCTION

Environmental exposures, including smoking, hormone-related factors, and metabolic factors, have been implicated in the etiology of rheumatoid arthritis (RA). A previous study has indicated that blood lipid levels may influence the development of RA. The objective of this study was to investigate the impact of serum total cholesterol and triglycerides on the risk of RA in a prospective study.

METHODS

Among participants in a large population-based health survey (n = 33,346), individuals who subsequently developed RA were identified by linkage to four different registers and a structured review of the medical records. In a nested case-control study, with controls, matched for age, sex, and year of inclusion, from the health survey database, the relation between serum lipids (levels of total cholesterol and triglycerides) and future RA development was examined.

RESULTS

In total, 290 individuals (151 men and 139 women) whose RA was diagnosed a median of 12 years (range of 1-28) after inclusion in the health survey were compared with 1160 controls. Women with a diagnosis of RA during the follow-up had higher total cholesterol levels at baseline compared with controls: odds ratio (OR) 1.54 per standard deviation; 95 % confidence interval (CI) 1.22-1.94. This association remained statistically significant in multivariate models adjusted for smoking and a history of early menopause and in analyses stratified by rheumatoid factor status and time to RA diagnosis. Total cholesterol had no significant impact on the risk of RA in men (OR 1.03; 95 % CI 0.83-1.26). Triglycerides did not predict RA in men or women.

CONCLUSIONS

A high total cholesterol was a risk factor for RA in women but not in men. This suggests that sex-specific exposures modify the impact of lipids on the risk of RA. Hormone-related metabolic pathways may contribute to RA development.

A high body mass index is associated with reduced risk of rheumatoid arthritis in men, but not in women

OBJECTIVE

To investigate the impact of overweight and obesity on the risk of RA.

METHODS

From two large population-based health surveys (30 447 and 33 346 participants), individuals who developed RA after inclusion were identified by linkage to four different registers and a structured review of the medical records. Matched controls were selected from the corresponding health survey database. The impact of overweight or obesity (BMI > 25 kg/m(2)) compared with normal BMI (18.5-25 kg/m(2)) on the risk of RA was examined in conditional logistic regression models, stratified by sex.

RESULTS

A total of 172 (36 men/136 women) and 290 (151 men/139 women) individuals were diagnosed with RA after inclusion in the two health surveys. The median time from inclusion to RA diagnosis was 5 years and 12 years, respectively. In men, being overweight or obese at inclusion in the health survey was associated with a reduced risk of subsequent development of RA in both cohorts [odds ratio (OR) = 0.33; 95% CI: 0.14, 0.76, and 0.60; 95% CI: 0.39, 0.91]. There was no such association in women (OR = 1.01; 95% CI: 0.65, 1.54, and 1.37; 95% CI: 0.86, 2.18). Estimates were similar in analyses adjusted for potential confounders, including smoking.

CONCLUSION

A high BMI was associated with a reduced risk of future RA in men, but not in women. Factors related to adipose tissue may contribute to mechanisms that are protective from RA in men.