Tag: rheumatoid arthritis

Categories : Implants and Prostheses Skeletal SystemTags :

Study Identifies Hip Implant Materials with Lowest Risk of Revision

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Hip implants with a delta ceramic or oxidised zirconium head and highly crosslinked polyethylene liner or cup had the lowest risk of revision during the 15 years after surgery, a new University of Bristol-led study has found. The research could help hospitals, surgeons and patients to choose what hip implant to use for replacement surgery.

The aim of the study, which appears in PLOS Medicine, was to establish hip implant materials at risk of revision. This would help orthopaedic surgeons, and patients, and to improve shared decision making before surgery by identifying hip implants with the lowest risk of revision.

The researchers analysed the UK’s National Joint Registry (NJR) data from 1 026 481 hip replacement patients carried out in the NHS and private sectors in England and Wales for up to 15 years after initial hip replacement operations (between 2003 to 2019). 

After reviewing hip implants from the NJR data, the research team found the risk of revision following a hip replacement is influenced by the type of material used in the bearing surface. Bearing surfaces are the moving parts of an artificial hip joint that glide against each other during activity.

The data indicated that hip implants with a delta ceramic or oxidised zirconium head and highly crosslinked polyethylene liner or cup had the lowest risk of revision throughout the 15 years following hip replacement surgery.

These findings were confirmed when the research team investigated the specific reasons for revision hip replacements being performed.  The data also showed 20 869 (2%) of hip replacement patients had to undergo revision after the initial surgery.

Senior author Dr Erik Lenguerrand, Senior Lecturer in Medical Statistics and Quantitative Epidemiologist in the Bristol Medical School: Translational Health Sciences (THS), said: “Our research has found the risk of hip replacement revision depends on the hip implant materials used in the original surgery.  The lowest risk of revision are from implants with delta ceramic or oxidised zirconium head and a highly crosslinked polyethylene (HCLPE) liner or cup.

“Further research is needed to find out the association of implant materials with the risk of rehospitalisation, re-operation other than revision, mortality and the cost-effectiveness of these materials.”

Michael Whitehouse, Professor of Trauma and Orthopaedics at Bristol Medical School: THS, and senior clinical lead for the paper, explained: “Our study has used data from one of the largest registries in the world that includes all public and private health care sectors in England and Wales. This means that the data is more generally applicable than that available previously, which was limited by broad groupings of implant types or much smaller study size. It highlights the importance of considering the whole structure that is created when implants are put together to make up a hip replacement rather than focusing on individual components.

“Our findings will help hospitals, surgeons and patients to choose hip implants and combinations of them with the lowest risk of revision following an initial hip replacement operation.”

Tim Wilton, Medical Director of the National Joint Registry (NJR), added: “We are always delighted when the data from the NJR can be used by researchers to produce important research of this kind which gives meaningful analysis to guide surgeons and patients in their decisions. An important value of the NJR data is that it allows researchers a unique insight to assess the long-term performance of different hip implant materials.

“By tracking the combinations of materials used and subsequent revision rates, this research highlights the role of implant material choice in surgical outcomes. This ensures that the materials used can be optimised for longevity and patient health. Surgeons would be well advised to study these findings carefully in relation to the implant choices they make, and to use the information in pre-operative discussions with their patients. As the demand for joint replacements continues to rise, this insight can be invaluable in reducing revision surgery.”

The research was not a randomised controlled trial and therefore it was not possible to control all factors that can influence the risk of revision.

The categorisation of hip implants used as part of hip replacements is often broad in national joint replacement surgery registries and does not fully show differences in revision risks associated within the different types of implant materials grouped together.

Source: University of Bristol

Categories : GastrointestinalTags :

Gut Health Signals could Transform Arthritis Treatment

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Gut Microbiome. Credit Darryl Leja National Human Genome Research Institute National Institutes Of Health

Changes in the gut microbiome before rheumatoid arthritis is developed could provide a window of opportunity for preventative treatments, new research suggests.

Bacteria associated with inflammation is found in the gut in higher amounts roughly 10 months before patients develop clinical rheumatoid arthritis, according to a longitudinal study by researchers at the University of Leeds. 

This new research might give us a major opportunity to act sooner to prevent rheumatoid arthritis.

Dr Christopher Rooney, Leeds Institute of Medical Research

Previous research has linked rheumatoid arthritis to the gut microbiome, which is the ecosystem of microbes in your intestines. But this new study, published in the Annals of the Rheumatic Diseases, reveals a potential intervention point. 

Lead researcher Dr Christopher Rooney, NIHR Academic Clinical Lecturer at the University of Leeds and Leeds Teaching Hospitals NHS Trust, said: “Patients at risk of rheumatoid arthritis are already experiencing symptoms such as fatigue and joint pain, and they may know someone in their family who has developed the disease. As there is no known cure, at-risk patients often feel a sense of hopelessness, or even avoid getting tested.  

“This new research might give us a major opportunity to act sooner to prevent rheumatoid arthritis.” 

Major opportunity for treatment

Funded by Versus Arthritis, the longitudinal study was conducted on 19 patients at risk of rheumatoid arthritis, with samples taken five times during a 15-month period.  

Five of these patients progressed to clinical arthritis, and the research showed they had gut instability with higher amounts of bacteria including Prevotella, which is associated with rheumatoid arthritis, about ten months before progression. The remaining 14, whose disease didn’t progress, had largely stable amounts of bacteria in their gut. 

Potential treatments that the researchers want to test at the 10-month window include changes to diet like eating more fibre, taking prebiotics or probiotics, and improving dental hygiene to keep harmful bacteria from periodontal disease away from the gut. 

The exact relationship between gut inflammation and rheumatoid arthritis development remains unclear. In a small number of patients within the study, the gut changes occurred before there were any changes to the joints observed by a rheumatologist, but more research is needed to determine whether these influence each other. 

Although bacteria is associated with rheumatoid arthritis, the researchers want to make it clear that there is no evidence this is contagious. 

Lucy Donaldson, director for research and health intelligence at Versus Arthritis, said: “At Versus Arthritis, we welcome the findings of this study which could give the clinicians of the future a crucial window of opportunity to delay – or even prevent – the onset of rheumatoid arthritis. This success is testament to the dedication of UK researchers who are working to personalise treatment and prevent chronic conditions that have significant impacts on a person’s ability to work, raise families and live independently.” 

The study initially took data from 124 individuals who had high levels of CCP+, an antibody that attacks healthy cells in the blood, which indicates risk of developing rheumatoid arthritis. The researchers compared their samples to 22 healthy individuals and seven people who had a new rheumatoid arthritis diagnosis.  

The findings from this larger group showed that the gut microbiome was less diverse in the at-risk group, compared to the healthy control group. 

The longitudinal study, which took samples from 19 patients over 15 months, revealed the changes in bacteria at ten months before progression to rheumatoid arthritis. 

The Leeds research team will now carry out an analysis of treatments that have already been trialled, to inform future testing of treatments at this potential 10-month intervention point. 

Source: University of Leeds

Categories : New Compounds and TreatmentsTags :

Abatacept may Hold Back Progression of Rheumatoid Arthritis

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Results from a Phase 2b clinical trial, published in The Lancet, provides hope for arthritis sufferers after it was shown that the biologic drug abatacept reduces progression to this agonising chronic inflammatory disease.

Rheumatoid arthritis is an autoimmune condition that typically (but not always) starts in middle age, with joint pain, swelling and significant disability. Until now there is no cure or prevention.

Abatacept is currently used as an effective second or third line treatment for people living with established rheumatoid arthritis and is given by weekly injections at home or intravenously in hospital.

Researchers from King’s College London recruited 213 patients at high risk of the disease to understand whether a year-long treatment of the biologic drug could be used to prevent progression to rheumatoid arthritis.

They recruited men and women over the age of 18 with early symptoms such as joint pain but no joint swelling, and treated half with the drug and half with a placebo every week for a year. The study drug was then stopped, and study participants monitored for a further 12 months.

After twelve months of treatment, 6% of patients treated with abatacept had developed arthritis compared to 29% in the placebo arm. By 24 months, the differences were still significant, with a total of 25% progressing to rheumatoid arthritis in the abatacept arm compared to 37% in the placebo arm.

Secondary outcomes for the trial showed that abatacept was associated with improvements in pain scores, function and quality of life measurements, as well as lower scores of inflammation of the lining of joints detectable by ultrasound scan.

Professor Andrew Cope, Professor of Rheumatology from School of Immunology & Microbial Sciences, said: “This is the largest rheumatoid arthritis prevention trial to date and the first to show that a therapy licensed for use in treating established rheumatoid arthritis is also effective in preventing the onset of disease in people at risk.

“These initial results could be good news for people at risk of arthritis as we show that the drug not only prevents disease onset during the treatment phase but can also ease symptoms such as pain and fatigue. This is also promising news for the NHS as the disease affects people as they age and will become more expensive to treat with a growing aging population.”

Philip Day, a 35-year-old software engineer and founder of FootballMatcher from Eltham, was at high-risk for rheumatoid arthritis. A keen football player, Philip’s joint pain deterred him from playing and affected his day-to-day life. He was enrolled in the trial in 2018, at the age of the 30, and was prescribed abatacept.

He said: “The pain got so terrible I stopped going to football, and I got lazier and felt progressively worse physically and mentally. The pain was unpredictable, it would show up in my knees one day, my elbows the next, and then my wrists or even my neck. At the time, my wife and I wanted to have children and I realised my future was pretty bleak if the disease progressed. I’d always wanted to be the kind of dad that played football with his son and I knew the pain would stop me from realising that dream.

“Enrolling in the trial was a no-brainer; it was a ray of hope at a dark time. Within a few months I had no more aches or pains and five years on I’d say I’ve been cured. Now, I can play football with my three-year-old son and have a normal life.”

One year’s treatment with abatacept costs the NHS about £10 000 (ZAR 238 000) per patient. Side effects include upper respiratory tract infections, dizziness, nausea and diarrhoea, but these are generally mild.

Professor Cope added: “There are currently no drugs available that prevent this potentially crippling disease. Our next steps are to understand people at risk in more detail so that we can be absolutely sure that those at highest risk of developing rheumatoid arthritis receive the drug.”

Source:

Categories : Cardiovascular DiseaseTags :

Potential New Treatment to Reverse Inflammation and Atherosclerosis in Rheumatoid Arthritis

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Image by Scientific Animations, CC4.0

Researchers from Queen Mary University of London have found that the molecule RvT4 enhances the body’s natural defences against atherosclerosis in patients with rheumatoid arthritis.

The mouse-based study, published in Nature Communications, shows that increasing levels of the RvT4 molecule in the body improves the ability of the body’s own defence mechanisms [macrophages] to reduce local inflammation and remove blockages in blood vessels.

This breakthrough in understanding the processes involved could lead to better treatments for people who have rheumatoid arthritis (RA), and who are at higher risk of developing cardiovascular disease.

Alongside the more widely-known symptoms of joint inflammation, people with the condition are also twice as likely as others to develop blood vessel disease.

One type of blood vessel disease seen in people with RA is atherosclerosis, which is caused by a build-up of ‘plaque’ along the artery walls, which can break free and cause heart attacks and strokes.

Understanding the reasons why RA patients are at increased risk of these cardiovascular problems is critical in developing better treatments for this group and others.

To gain a better understanding of the causes of blood vessel disease in patients with RA, researchers explored the role of a group of molecules called 13-series resolvins (RvTs). In experimental arthritis the levels of one of these molecules, RvT4, are markedly reduced, a phenomenon that associates with a higher degree of blood vessel disease.

This study was designed to explore why this might be the case.

The findings

The study found that treating arthritic mice with RvT4 reduced blood vessel inflammation by re-programming macrophages, which accumulate in the diseased vessels, to release stored lipids.

Researchers observed that these lipids were preventing the macrophage from carrying out their usual work of clearing dead cells and reducing localised inflammation in blood vessels.

Once freed of their lipid burden, the macrophages were able to move and work much more effectively to reduce the causes of atherosclerosis.

The observation that RvT4 restores protective macrophage biological activities is an exciting finding.

RA patients also often present with metabolic dysfunction and this is thought to exacerbate vascular disease.

The study found that administration of RvT4 to mice engineered to develop characteristics of metabolic dysfunction, advanced atherosclerosis, and arthritis led to an overall decrease in lipoprotein-associated cholesterol in plasma and an increase in the ratio of HDL-associated cholesterol to total cholesterol.

Jesmond Dalli, Professor in Molecular Pharmacology and Lipid Mediator Unit Director at the William Harvey Institute, Queen Mary University of London, said: “The study is important because it identifies for the first time the loss of RvT4 production as a potential new cause of blood vessel inflammation in the context of arthritis, offering a mechanistic explanation on the cause of this important disease in RA patients. It also showed that RvT4 restores the biological activities of lipid loaded macrophages by promoting lipid breakdown and efflux from the cells, an observation that can guide the development of new treatments to limit the incidence and/or severity of cardiovascular disease in patients with RA.”

Source: Queen Mary University of London

Categories : Immune SystemTags :

Immunomodulatory Rheumatoid Arthritis Drugs might Prevent Autoimmune Thyroid Disease

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Source: Pixabay

Anti-rheumatic drugs used for rheumatoid arthritis (RA) might prevent the development of autoimmune thyroid disease, according to a new observational study by researchers from Karolinska Institutet which is published in the Journal of Internal Medicine.   

Patients with RA at increased risk of autoimmune thyroid diseases such as Hashimoto’s disease and Graves’ disease. While patients with RA are usually treated with immunomodulatory drugs that affect the immune system, such drugs are rarely used in autoimmune thyroid diseases. Instead, such patients are treated with thyroid hormones such as levothyroxine to compensate for the changes in normal thyroid function that accompany autoimmune thyroid disease.  

In this study, the researchers wanted to investigate whether immunomodulatory drugs that reduce inflammation in the joints of patients with RA might also reduce the risk of these patients developing autoimmune thyroid disease. Previous studies in mice suggest that so-called DMARDs, a type of immune-modulatory drugs used to treat rheumatoid arthritis, can reduce inflammation in the thyroid gland. Still, knowledge of whether this effect also applies to humans is limited, according to the research team.   

The researchers used data between 2006 and 2018 on over 13 000 patients with rheumatoid arthritis and their treatment, as well as data from over 63 000 individuals in a matched control group without rheumatoid arthritis.  

The researchers found that the risk of developing an autoimmune thyroid disease among RA patients was lower after their onset of the rheumatic disease than before diagnosis.  

The most greatest risk reduction was seen in RA patients treated with immunomodulatory drugs or ‘biological DMARDs’. In these patients, the risk of autoimmune thyroid disease was 46% lower than in the control group without rheumatoid arthritis.   

“These results support the hypothesis that certain types of immunomodulatory drugs could have a preventive effect on autoimmune thyroid disease,” says Kristin Waldenlind, researcher at the Department of Medicine, Solna, Division of Clinical Epidemiology, Karolinska Institutet, specialist in rheumatology at Karolinska University Hospital and first author of the study. She continues:  

“Our results do not prove that it is the treatment with immunomodulatory drugs that led to the reduced risk of autoimmune thyroid disease, but provide support for this hypothesis. The results, if they can be replicated in further studies, open up the possibility of studying more directly in clinical trials whether the immunomodulatory drugs currently used for rheumatoid arthritis could also be used for the early treatment of autoimmune thyroid disease, ie for new areas of use of these drugs, known as drug repurposing.”

Source: Karolinksa Institutet

Categories : Ageing Immune SystemTags :

New Approach May Take the Guesswork out of Selecting Treatments for RA

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Photo by Towfiqu barbhuiya: https://www.pexels.com/photo/person-feeling-pain-in-the-knee-11349880/

New research reported in the journal Nature could lead to new targeted treatments for rheumatoid arthritis (RA). The findings showed that guesswork could be taken out of selecting treatments for each patient, and this might one day also be extended to other autoimmune conditions.

The study was led by University of Colorado School of Medicine faculty members Fan Zhang, PhD, and Anna Helena Jonsson, MD, PhD. The Accelerating Medicines Partnership: Rheumatoid Arthritis and Systemic Lupus Erythematosus (AMP: RA/SLE) Network collected inflamed tissue from 70 patients with RA from across the country and the United Kingdom. Jonsson supervised the team of scientists who processed these samples for analysis, and Zhang led the computation analysis of the data. These efforts yielded a cell atlas encompassing more than 300 000 cells from synovial tissue. Further analysis revealed that there are six different subgroups of RA based on their cellular makeup.

“We hope the data will help us discover new treatment targets,” says Jonsson, assistant professor of rheumatology. “We wanted to make it public so that researchers across the country and across the world can continue working on new treatment ideas for rheumatoid arthritis going forward.”

No more guess-and-check

Jonsson, a practicing rheumatologist as well as a researcher, knows that RA patients respond differently to different treatments. Until now, she says, rheumatologists used a “guess and check” method to find a treatment that works for an individual patient.

With the new data and powerful computational classification methods developed by Zhang and the computational analysis team, the researchers were able to quantitatively classify RA types into what they call ‘cell-type abundance phenotypes’, or CTAPs. Developed methods, together with the new cell atlas, can start to identify which patients will respond to which treatments.

“Even when you classify rheumatoid arthritis inflammation using these simple markers – T cell markers, B cells, macrophages and other myeloid cells, fibroblasts, endothelial cells – what we found is that each of those categories is associated with very specific kinds of pathogenic cell types we’ve already discovered,” Jonsson says. “Previous rheumatoid arthritis research found that T cell populations called peripheral helper T cells are relevant in rheumatoid arthritis, as are B cells called antibody-producing B cells, and other specific cell types. What we found is that they’re usually not found all together.

“For example, the peripheral helper cells are found with the B cells in only one category of RA, and the pathogenic macrophage populations tend to exist in a different category. Because of this, we can start asking questions about how these specific partners work together.”

Source: University of Colorado Anschutz Medical Campus

Categories : AgeingTags :

Immunomodulator Keeps Subclinical Arthritis from Developing into Full-blown Form

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Photo by Towfiqu barbhuiya: https://www.pexels.com/photo/person-feeling-pain-in-the-knee-11349880/

In a 12-month trial involving patients with “preclinical” rheumatoid arthritis, treatment with the immunomodulator abatacept (Orencia) kept the condition from becoming clinical, according to findings presented at the European Alliance of Associations for Rheumatology (EULAR) annual meeting.

Rheumatologists have long sought to nip rheumatoid arthritis (RA) in the bud, with many studies supporting early aggressive treatment on RA diagnosis. This has never been recommended for biologic therapies however.

Nevertheless, some patients show up at arthritis clinics with a few painful joints and other features such as RA-related serum biomarkers that suggest progression to full-blown RA is likely. Would aggressive treatment help slow their decline into RA?

In a phase IIb randomised trial involving patients in the UK and Netherlands who were at high risk for developing RA, only seven of the 110 assigned to abatacept had gone on to develop clinical arthritis after 1 year, compared with 30 of 103 in a placebo group.

The effect waned after abatacept was stopped at the one-year mark, and in the following year, 20 more patients in the abatacept group developed clinical arthritis, as did another eight in the placebo group.

Though the abatacept regimen held the edge for a full two years, projections showed that it was likely that the abatacept group would catch up with additional follow-up. At the same time, abatacept had no particular safety issues and thus could likely be continued.

A decade ago, Andrew Cope, MD, MBBS, of King’s College London colleagues thought about aggressive prevention, registering the current trial, Arthritis Prevention in the Pre-clinical Phase of RA with Abatacept (APIPPRA), in 2014. In a 2019 description of the protocol, they explained the selection of abatacept because “it targets immune reactions early in the chain of events leading to inflammation in RA. It functions by interrupting the interaction between T cells and antigen-presenting cells, attenuating the co-stimulatory signals required for T-cell activation, differentiation and effector responses,” thereby resulting “in downstream immunomodulatory effects on other inflammatory cells of the immune system.”

Participants had to show joint pain but no synovitis, plus either test positive for anti-citrullinated protein antigen (ACPA) antibodies and for rheumatoid factor (RF), or show high levels of ACPA antibodies without RF. The primary endpoint was development of clinically apparent arthritis in at least three joints or diagnosis of RA according to standard criteria.

While the preventive effect seen in the primary analysis did not hold up across the whole sample, Cope noted that it appeared more so in one very-high-risk subgroup: 49 patients who had some level of IgG ACPA antibodies and who were also positive for a series of other biomarkers, including RF, IgA ACPA antibodies, anti-carbamylated protein antibodies, and anti-acetylated peptide antibodies. For this subgroup, only about 10% of those who had taken abatacept progressed to clinical arthritis after two years, versus 50% of those assigned to placebo.

Source: MedPage Today

Categories : Diseases, Syndromes and Conditions Immune SystemTags :

Autoimmune Disorders Now Affect Roughly One in Ten Individuals

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A population-based study of 22 million people in the UK estimates that around one in ten individuals in the UK now live with an autoimmune disorder. The findings, published in The Lancet, also highlight important socioeconomic, seasonal and regional differences for several autoimmune disorders, providing new clues as to what factors may be involved in these conditions.

There are more than 80 known autoimmune diseases, including conditions like rheumatoid arthritis, type 1 diabetes and multiple sclerosis, some of which have been increasing in the last few decades.

This has raised the question whether overall incidence of autoimmune disorders is on the rise and what factors are involved, such as environmental factors or behavioural changes in society. The exact causes of autoimmune diseases remain largely unknown, including how much can be attributed to a genetic predisposition to disease and how much is down to exposure to environmental factors.

The study used anonymised electronic health data from 22 million individuals in the UK to investigate 19 of the most common autoimmune diseases. The authors examined whether incidence of autoimmune diseases is rising over time, who is most affected by these conditions and how different autoimmune diseases may co-exist with each other.

They found that the 19 autoimmune diseases studied affect around 10% of the population. This is higher than previous estimates, which ranged from 3–9% and often relied on smaller sample sizes and included fewer autoimmune conditions. The analysis also highlighted a higher incidence in women (13%) than men (7%).

The research discovered evidence of socioeconomic, seasonal and regional disparities for several autoimmune disorders, suggesting that these conditions are unlikely to be caused by genetic differences alone. This observation may point to the involvement of potentially modifiable risk factors such as smoking, obesity or stress. It was also found that in some cases a person with one autoimmune disease is more likely to develop a second, compared to someone without an autoimmune disease.

Dr Nathalie Conrad at the University of Oxford said: “We observed that some autoimmune diseases tended to co-occur with one another more commonly than would be expected by chance or increased surveillance alone. This could mean that some autoimmune diseases share common risk factors, such as genetic predispositions or environmental triggers. This was particularly visible among rheumatic diseases and among endocrine diseases. But this phenomenon was not generalised across all autoimmune diseases. Multiple sclerosis, for example, stood out as having low rates of co-occurrence with other autoimmune diseases, suggesting a distinct pathophysiology.”

These findings reveal novel patterns that will inform the design of further research into the possible common causes of different autoimmune diseases.

Professor Geraldine Cambridge at UCL Medicine said: “Our study highlights the considerable burden that autoimmune diseases place upon individuals and the wider population. Disentangling the commonalities and differences within this large and varied set of conditions is a complex task. There is a crucial need, therefore, to increase research efforts aimed at understanding the underlying causes of these conditions, which will support the development of targeted interventions to reduce the contribution of environmental and social risk factors.”

Source: University College London

Categories : Diseases, Syndromes and Conditions Environmental EffectsTags :

Strong Link Between Polycyclic Aromatic Hydrocarbons and Rheumatoid Arthritis Risk

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Exposure to polycyclic aromatic hydrocarbons (PAH), formed from burning various substances such as coal, wood or tobacco, or from grilled meat, is strongly linked to a person’s risk of developing rheumatoid arthritis, suggests research published in the open access journal BMJ Open.

These chemicals also seem to account for most of smoking’s impact on risk of the disease, the findings indicate. Growing evidence links several environmental toxicants with various long term conditions. But few studies have looked at their association with inflammatory conditions, such as rheumatoid arthritis, which is thought to arise from an interplay between genes, sex, and age, and environmental factors, including smoking, nutrition, and lifestyle.

To try and shed some light on the potential role of environmental exposure on rheumatoid arthritis risk, the researchers drew on responses to the nationally representative US National Health and Nutrition Examination Survey (NHANES) between 2007 and 2016.

NHANES evaluates a wide variety of toxicants, including PAH; chemicals used in the manufacture of plastics and various consumer products (PHTHTEs); and volatile organic compounds (VOCs), derived from paints, cleaning agents, and pesticides, among other things; along with data related to health, nutrition, behaviours and the environment.

The study included 21 987 adults, 1418 of whom had rheumatoid arthritis and 20 569 of whom didn’t. Blood and urine samples were taken to measure the total amount of PAH (7090 participants), PHTHTEs (7024), and VOCs (7129) in the body.

The odds of rheumatoid arthritis were highest among those in the top 25% of bodily PAH levels, irrespective of whether or not they were former or current smokers.

After accounting for potentially influential factors, including dietary fibre intake, physical activity, smoking, household income, educational attainment, age, sex, and weight (BMI), only one PAH, 1-hydroxynaphthalene, was strongly associated with higher odds (80%) of the disease.

PHTHTE and VOC metabolites weren’t associated with heightened risk after accounting for potentially influential factors.

Somewhat surprisingly, however, smoking wasn’t associated with heightened rheumatoid arthritis risk either, after accounting for PAH levels in the body. 

And further analysis to separate out the influences of PAH and smoking showed that bodily PAH level accounted for 90% of the total effect of smoking on rheumatoid arthritis risk.

This is an observational study, and as such, can’t determine cause. And the researchers acknowledge various limitations to their findings, including that measurements of environmental toxicants in fat (adipose) tissue weren’t available.

Nor did they measure heavy metal levels which have previously been linked to rheumatoid arthritis risk. Cigarettes are a major source of the heavy metal cadmium.

But they write: “To our knowledge, this is the first study to demonstrate that PAH not only underlie the majority of the relationship between smoking and [rheumatoid arthritis], but also independently contribute to [it]. 

“This is important as PAH are ubiquitous in the environment, derived from various sources, and are mechanistically linked by the aryl hydrocarbon receptor to the underlying pathophysiology of [rheumatoid arthritis].”

They add: “While PAH levels tend to be higher in adults who smoke…other sources of PAH exposure include indoor environments, motor vehicle exhaust, natural gas, smoke from wood or coal burning fires, fumes from asphalt roads, and consuming grilled or charred foods.

“This is pertinent as households of lower socioeconomic status generally experience poorer indoor air quality and may reside in urban areas next to major roadways or in high traffic areas.” These people may therefore be particularly vulnerable, they suggest.

Source: The BMJ

Categories : COVID Diseases, Syndromes and ConditionsTags :

Prior COVID Infection Linked to New Autoimmune Conditions

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In a new entry to the growing list of lasting complications from COVID infection, a large German cohort study of over 600 000 COVID patients indicates that new autoimmune conditions may result from previous COVID infection. The findings, which are awaiting peer review on the MedRxiv preprint server, show that the odds of new autoimmune conditions appear to increase in line with the severity of COVID infection.

After the acute phase of infection, some people may develop long-lasting symptoms, known as post-COVID, which are consistent with COVID infection and last more than 12 weeks. Most studies to date have focused on symptoms that partly wane over time. Many studies examined a small selective sample of patients, and only a few studies included a control group or information on chronic health conditions, such as SARS-CoV-2 infection.

Compared to post-COVID emergence of cardiovascular and other diseases, autoimmune diseases are less discussed in the literature, although autoantibodies could be found in patients after SARS-CoV-2 infection. So far there is limited evidence on newly manifested autoimmune diseases after an infection based on several case reports and one recent cohort study using UK health record data. In addition, COVID itself has some similarities with systemic autoimmune rheumatic diseases, which could make diagnosis difficult.

The researchers selected a cohort from German routine health care data, identifying individuals with polymerase chain reaction (PCR)-confirmed COVID through December 31, 2020. Patients were matched 1:3 to control patients without COVID. Both groups were followed up until June 30, 2021. We used the four quarters preceding the index date until the end of follow-up to analyse the onset of autoimmune diseases during the post-acute period. The researchers calculated the incidence rates (IR) per 1000 person-years for each outcome and patient group, and estimated incidence rate ratios (IRRs) of developing an autoimmune disease conditional on a preceding COVID.

In total, 641 704 patients with COVID were included. When comparing the incidence rates in the COVID and matched control groups, the researchers found a 42.63% higher likelihood of acquiring autoimmunity for patients who had suffered from COVID. This estimate was similar for common autoimmune diseases, such as Hashimoto thyroiditis, rheumatoid arthritis, or Sjögren syndrome. The highest IRR was observed for autoimmune disease of the vasculitis group. Patients with a more severe course of COVID were at a greater risk for incident autoimmune diseases. These risk increases were as follows:

  • 41% higher risk of Grave’s disease
  • 42–45% higher risk of rheumatoid arthritis
  • 25% higher risk of type 1 diabetes
  • 27-29% higher risk of Crohn’s disease

The researchers concluded that SARS-CoV-2 infection is associated with an increased risk of developing new-onset autoimmune diseases after the acute phase of infection.