Rheumatoid arthritis (RA) is a chronic autoimmune disorder characterized by inflammation and pain in the joints. This means your body’s immune system, which normally protects you, mistakenly attacks your joints, causing inflammation and pain. The condition is more common in women, and Nordic countries have a higher prevalence of the disease than the global average.
The exact cause of RA is complex as numerous factors play a part in rheumatoid arthritis risk. It is believed to be a combination of your genes and environmental factors, like exposure to certain toxins or dietary habits, which can trigger inflammation in those who are genetically susceptible. This local inflammation can then progress to affect other parts of your body, like your lungs, blood vessels, liver, and kidneys.
Symptoms of rheumatoid arthritis can sometimes start years it before can be officially diagnosed, but your doctor can often detect the condition this early by looking for specific markers in your blood, like anti-citrullinated peptide antibodies (ACPA) and rheumatoid factors (RF). However, it’s important to remember that some individuals can still have RA even if these markers are negative, which we call seronegative RA, and this can be up to a third of RA patients.
How to prevent RA or limit its progress?
To answer this question, it is imperative to understand the risk factors involved in the development and progression of this condition. Similar to most other conditions, risk factors of RA can be categorized as
- Non-modifiable, which are basically things that you have no control over such as your genes, gender, race or age, and
- Modifiable risk factors which are the environmental and lifestyle factors that you can control and adjust to your benefit.
The good news is, in many if not most of current common health conditions, including many autoimmune conditions, cardiovascular disorders, diabetes and even cancer, these environmental/lifestyle risk factors account for the majority of the risk of developing the condition.
This should empower you to take action and control over your health, to do your best to prevent these modifiable factors from triggering your potentially predisposed genes from developing a certain condition. On the other hand, if you have already been diagnosed with the condition, then doing so can help to halt the progression of the disease and even possibly reverse it.
Biological/genetic Factors for Rheumatoid Arthritis Risk
Age
While RA is often seen in older individuals above the age of 60, recent studies shows that RA antibodies actually develop many years before symptoms appear. RA can fully manifest at a younger age, which is known as early-onset RA. The risk of developing RA may not necessarily always increase with age as we previously thought, but still age may play a factor.
Sex
RA is more prevalent in females than males. This difference may be attributed to hormonal factors, variations in immune responses to infections, or differences in the innate immune system.
Genetics
The primary RA genetic risk factor is known as the HLA shared epitope (HLA-SE), which is located on chromosome 6, also Large-scale genome-wide association studies (GWAS) have identified over 100 non-HLA loci associated with the development of RA.
However, genetic factors only account for about 40-60% of the risk of developing RA, and the presence of these gene variants does not guarantee the development of RA, it just means that a higher predisposition to developing the condition exists, and it will probably require other factors to trigger those genes. Additionally, the exact role of these genes in the disease process remains unclear, however, they may not only affect the disease development but can also influence its progression or response to treatment.
Environmental and Lifestyle Factors
Cigarette Smoking
Cigarette smoking is a well-established environmental risk factor for RA. Extensive research indicates that smoking can significantly increases your risk of developing RA, particularly the seropositive type associated with rheumatoid factor (RF) and circulating anti-citrullinated protein antibodies (ACPA). In fact, Smoking is now believed to potentially be responsible for about 20% of all cases and up to 35% of ACPA-positive RA cases.
A comprehensive meta-analysis highlighted a 26% increased risk of RA among individuals with a smoking history of 1-10 pack-years (a pack a day for a year up to 10 years). The risk escalates almost twofold in those with over 20 pack-years of smoking history (a pack a day for the last 20 years, or two packs a day for the last 10 years). Notably, the correlation between smoking and RA is more robust for RF-positive RA than RF-negative RA.
If you are a man, this could be even worse for you! Men appear to be more susceptible to smoking-related RA than women. Moreover, individuals carrying two copies of the HLA-DRB1 shared epitope (SE) gene, a known genetic risk factor for RA, experience an even higher risk when they smoke; a study reported that 55% of the RA cases carrying those genes could be attributed to smoking. This underscores a potent gene-environment interaction in the development of RA. On the bright side, the risk can decline significantly after smoking cessation, especially for ACPA-negative RA.
Passive Smoking
Research results on passive smoking and its association with RA is not as concrete, current available studies suggest that exposure to secondhand smoke might increase the risk of RA in adults, particularly with exposure during childhood, and the risk is even more pronounced in children exposed to maternal smoking.
Air Pollution
The role of air pollution in rheumatoid arthritis risk is an emerging area of research. Studies examining the proximity of residences to highways and exposure to high levels of pollutants such as ozone (O3) and carbon monoxide (CO) suggest a potential link to increased RA risk.
A 2024 study found that living in areas with higher particulate matter PM2.5 from pollution was associated with an increased risk of RA, while living in areas with higher green space was linked to a reduced risk of RA. However, the study also reported that if there is high pollution/PM2.5, it can offset the beneficial effect of living in high green areas.
Vitamin D Deficiency and Rheumatoid Arthritis Risk
Vitamin D has emerged as a significant hormone with immunomodulatory properties, demonstrating anti-inflammatory effects through direct interaction with various immune cells.
Numerous observational studies have shown a high prevalence of vitamin D deficiency among RA patients, prompting investigations into its potential role in RA development. However, large prospective cohort studies have yielded conflicting results, with some indicating an inverse relationship between vitamin D intake and RA incidence, while others found no such association. A meta-analysis of these studies revealed a 24% risk reduction in high versus low vitamin D intake groups. However, the reliance on dietary questionnaires to assess vitamin D status, which is subject to fluctuations due to sun exposure and other factors, may affect these findings.
Interestingly, a study examining cumulative ultraviolet-B (UVB) light exposure, the primary source of vitamin D, within a cohort that previously showed no association between dietary vitamin D intake and rheumatoid arthritis risk, demonstrated a significant decrease in RA risk with higher UVB exposure.
Vitamin D Supplementation and RA Prevention
Despite these suggestive findings, a large randomized controlled trial (RCT) failed to establish a preventive effect of daily calcium and vitamin D supplementation on RA risk in post-menopausal women.
Vitamin D Deficiency and RA Prognosis
While the role of dietary vitamin D in RA prevention remains uncertain, stronger evidence supports an association between vitamin D deficiency and a poorer prognosis in RA patients. This includes increased disease activity, functional impairment, and reduced health-related quality of life (HRQoL).
To summarize, we know that vitamin D deficiency (low blood levels of vitamin D) is associated with higher prevalence of RA, but we don’t know for sure whether consuming more dietary vitamin D can reduce the risk of RA. However, we are more certain, that vitamin D obtained from sun exposure can potentially significantly reduce the risk. Also, it is more evident that vitamin D deficiency worsen the disease symptoms and prognosis.
Here are my product recommendation:
Diet
Obesity
Your weight can play an important role in determining your risk of developing rheumatoid arthritis (RA). Studies show a clear link between obesity and RA, with a 21% increased risk, the risk of RA increased by 13% for every 5 kg/m 2 extra in body mass index (BMI). The association appears stronger in women and possibly in those with seronegative RA with 47% increase in risk, although research on the latter is inconclusive.
These findings align with the observed increase in obesity rates among RA patients over the past two decades. While obesity can be a marker for other lifestyle factors (such as unhealthy eating habits, smoking and alcohol consumption), it might directly contribute to RA through metabolic and hormonal mechanisms.
Excess fat tissue can release inflammatory molecules, disrupt your hormone balance, and lead to higher estrogen levels (which is linked to RA through various mechanisms, hence, the higher prevalence in women). Additionally, obesity-related high cholesterol has been observed in individuals who develop RA, particularly women.
Fish Consumption
The relationship between fish consumption and rheumatoid arthritis risk is inconclusive. Some studies suggest that fish, rich in omega-3 fatty acids, may have a protective effect against RA, particularly in individuals who have never smoked. However, some studies fails to establish a significant association between fish intake and RA development.
That being said, the evidence is more substantial when it comes to the impact of fish oil on diagnosed symptomatic RA, clinical trials have demonstrated that it can significantly improve symptoms such as pain and enhance the clinical response to medications (DMARDs).
Olive Oil, Fruits, and Vegetables
The impact of olive oil on rheumatoid arthritis risk has been examined with most studies indicate a lower RA risk with high olive oil consumption, while few others did not find a significant correlation. Similarly, diets high in cooked vegetables and fruits have shown inverse associations with RA risk, suggesting potential protective effects.
Meat Consumption
There is a potential connection between red meat and this inflammatory condition. One study investigated how red meat consumption might influence the age at which RA begins in women. Interestingly, women who frequently enjoyed red meat experienced an earlier onset of RA compared to those who ate it less often. In fact, after accounting for factors like age and weight, high red meat intake was linked to developing RA approximately 6.5 years earlier. This connection was particularly strong in women who smoked or were overweight.
Another large study tracked nearly 170,000 women and found that moderate red meat consumption was associated with an increased risk of RA in women aged 55 and younger. Scientists speculate that this could be due to the buildup of fat tissue, which can fuel inflammation throughout the body and potentially trigger RA.
A 2000 study that looked at red meat consumption and RA prevalence across eight different countries found a strong positive correlation. Essentially, countries where people ate more red meat tended to have higher rates of RA. Similarly, another study linked a high intake of meat in general to an increased risk of inflammatory polyarthritis.
On the other hand, some large cohort studies haven’t found a clear connection between red meat and RA risk. For example, an older research study which included 82,063 women monitored from 1980 to 2002, showed no association between red meat (or poultry and fish) and the likelihood of developing RA.
Clearly, the relationship between red meat and RA is complex. While a lot of research suggests that red meat may contribute to an earlier onset of RA, particularly in certain groups, some studies haven’t confirmed this link in overall population, as its consumption may differently affect the mechanisms involved in the development of RA based on sex and age.
Coffee, Tea, and Beverages
Coffee consumption has been associated with an increased risk of RA in some studies, especially RF-positive RA. However, the evidence is not uniform, Studies on the link between caffeinated beverages and rheumatoid arthritis (RA) have produced mixed results.
One meta-analysis that included five studies involving 134,901 participants reported an increased risk of RA with coffee consumption, but no association with tea.
However, a more recent prospective cohort study including 76,853 individuals found no increased RA incidence with coffee consumption (caffeinated or decaffeinated). Interestingly, this study found that caffeinated non-herbal tea intake was linked to a 40% increase in risk, and the risk increased with increasing the amount of teas consumed per day.
The findings of these studies disagree with each other, and therefore the link between coffee, tea and RA remains unclear, however, when in doubt, I would advise you to always caution on the safe side, particularly with the amount of caffeine you consume.
Sugar-Sweetened Soda
This is an important one for everybody, as consumption of sugar-sweetened beverages has been linked to an increased risk of RA in some studies. This association is particularly noted for seropositive RA, this is because high sugar intake can influence immune responses and inflammation.
Alcohol Consumption
This may be surprising for many of you but alcohol consumption has actually been associated with a decreased risk of RA in some observational studies. A meta-analysis of a large number of studies has shown that moderate alcohol consumption may reduce the risk of developing rheumatoid arthritis (RA) by 17%, particularly for women and those who consistently consume around 9g of alcohol daily for 10 years or more. This is because alcohol contains components that could suppress the immune response and inflammation.
This doesn’t mean that if you’re not drinking you start now, or you should increase your consumption, on the contrary, as alcohol poses a significant risk for many other disorders and chronic conditions including cancer! So, if you are already consuming alcohol, limit your consumption and try to opt for red wine over any other type of alcohol due to its high content of resveratrol that can offer some protection against RA and even improve its symptoms due to its anti-inflammatory, and anti-oxidant properties.
Dietary Patterns
Rather than focusing on individual foods or nutrients, analyzing overall dietary patterns can provide insights into the relationship between diet and RA. Studies have explored dietary patterns impact on RA, such as the Mediterranean diet, which is rich in fruits, vegetables, olive oil, and fish. Mediterranean diet is hypothesized to contribute to the varying prevalence of RA across northern and southern Europe where lower RA rates is seen in the south, where this diet is more widespread, than the north.
In addition, other genetic and environmental factors, such as sun exposure and vitamin D levels, may also play a part in this variation. However, not all studies have managed to confirm the reduced risk associated with this diet. Studies are more confident that this diet may reduce inflammation, pain, and improve function in patients who are already diagnosed with RA, particularly when combined with physical activity.
Mineral Nutrition
Iron is an essential mineral that is involved in many important physiological processes. Iron deficiency has been linked to an increased risk of RA. Studies have provided some evidence that iron status may increase the risk of RA. A 2020 study found that if you are genetically predisposed to have high iron status, this may put you at lower odds of developing RA.
Furthermore, another study reported that those with RA who also have anemia are more likely to exhibit severe joint symptoms, and if the anemia is treated successfully, there may be improvement in symptoms and response to other RA treatments. On the other hand, studies did not find consistent evidence that other micronutrients, such as calcium, magnesium, copper, and zinc, were associated with RA.
Socioeconomic Factors and Rheumatoid Arthritis Risk
Unfortunately, your socioeconomic situation can impact your rheumatoid arthritis risk as well. Research has shown a correlation between lower socioeconomic status and an increased risk of developing rheumatoid arthritis (RA), particularly seropositive RA. This association persists even after accounting for factors like smoking and lifestyle.
Specifically, lower levels of education, both individual and parental, have been independently linked to a higher rheumatoid arthritis risk, this is potentially due to how low education can lead to socioeconomic deprivation, increasing the risk of environmental exposures such as infections, air pollution, chemical exposure and poor diet. Low education and/or socioeconomic status is also more prevalent among individuals in manual, or blue-collar jobs, which further exposes them to higher risks as seen below.
Additionally, early life socioeconomic disadvantages such as food insecurity and young maternal age have been associated with greater RA development in adulthood.
What you do for work
If your job involves working in manual labor, you may face a heightened risk of developing rheumatoid arthritis (RA). Individuals working in these jobs sadly often have higher exposure to environmental risk factors;
Exposure to Harmful Agents
Manual labor jobs often involve exposure to substances like inorganic dust, textile dust, and other respiratory irritants, which are recognized risk factors for RA. Additionally, occupational exposure to silica dust is another significant risk factor for RA, especially among men.
Studies consistently show an association between silica exposure and an increased risk of seropositive RA. There is a clear dose-response relationship, indicating that higher levels of silica exposure correlate with a greater risk of RA. Furthermore, smoking, which is also common among this population, can exacerbate this risk, suggesting a synergistic effect between silica exposure and cigarette smoke.
Contact with Mineral Oil and Pesticides
Certain professions, such as auto mechanics and farmers, frequently handle mineral oil and pesticides, respectively. Both of these substances have been linked to the development of RA. Studies have shown a dose-response relationship between pesticide exposure and RA risk, both in adulthood and childhood.
Repetitive Physical Workload
Prolonged repetitive physical work, common in blue-collar jobs, has been associated with an increased risk of both ACPA-positive and ACPA-negative RA. This risk factor may interact with the HLA-SE gene in ACPA-positive individuals, meaning if you have this genetic predisposition, then performing this type of repetitive physical work is more likely to interact with this gene and trigger RA.
Shift work
Shift work is associated with an increased risk of developing RA, particularly in females. shift work defined as working outside regular day shifts (9 to 5), it is categorized into early morning, evening and night shift. The irregular hours of shift work can disrupt the body’s natural sleep-wake cycle, leading to chronic inflammation and immune system problems. This disruption may make shift workers more susceptible to autoimmune diseases like RA. Many shift workers do alternate shifts which could negatively impact their circadian rhythm even more
Studies have shown a connection between shift work and various health issues, including autoimmune thyroid disorders, multiple sclerosis, diabetes, cardiovascular disease, and cancer. Interestingly, working permanently only at night was associated with lower risk of particularly developing RA, this is because working exclusively at night may lower the body’s production of melatonin, a hormone that is involved in the sleep regulation but also may play a part in promote rheumatoid arthritis (RA) development. Other types of shift work don’t seem to have this effect.
Cold Working Environments
Working in cold environments has been found to increase the odds of developing RA by 50%, with a more pronounced effect in ACPA-positive individuals (60% increased odds) compared to ACPA-negative individuals (40% increased odds). A dose-response relationship was observed for indoor work, which means your risk of developing RA is higher with increasing total amount of time working in cold indoor environment such as an overly AC cooled workplace and or a place with no heating or insulation in the winter. The risk is even higher if this work in cold place involves repetitive hand/finger movements.
Work-Related Stressors
Work-related stress, and workplace conflict have also been identified as potential risk factors for RA.
Infections
Improved sanitation has been linked to a decrease in the occurrence of rheumatoid arthritis (RA), giving support to the theory that infections may play a role in the condition. Studies have explored how various microbial agents, including viruses and bacteria, might contribute to RA.
Potential mechanisms include triggering a broad immune response, molecular mimicry where microbial proteins resemble human proteins, or other complex biological processes. Here we will explore the evidence supporting the association between specific infections and RA:
The Gut’s Role in Rheumatoid Arthritis
Maintaining a healthy gut is an important piece of the puzzle when it comes to reducing your rheumatoid arthritis risk. Over the past decade, researchers have increasingly focused on the gut microbiota and its potential influence on immune balance and disease development. A growing body of evidence suggests a significant connection between disruptions in this gut ecosystem, known as dysbiosis, and the inflammatory rheumatic disease, rheumatoid arthritis (RA).
Researchers have observed distinct changes in the gut microbiota of RA patients. These changes include an overall decrease in microbial diversity, along with an increase in certain bacteria like Prevotella copri and Lactobacillus spp., and a decrease in others such as Bacteroides spp. Remarkably, a large-scale study analyzing the entire gut microbiome found that patterns of dysbiosis (imbalance in gut bacteria) in both fecal and oral samples could differentiate RA patients from healthy individuals with high accuracy.
Recent studies are providing stronger evidence for a direct causal link. Research indicates that gut dysbiosis characteristic of RA can activate autoreactive T cells, immune cells that mistakenly attack the body’s own tissues. Furthermore, specific proteins from Prevotella copri have been shown to trigger immune responses characteristic of RA. Intriguingly, Prevotella spp. has also been found to be enriched in individuals who are at increased risk for developing RA, further implicating gut dysbiosis in the disease process.
Adding to the evidence, studies have shown that dysbiosis patterns in both the oral and gut microbiome of newly diagnosed, untreated RA patients correlate with disease activity. These imbalances in the gut microbiome improve with conventional synthetic DMARD (csDMARD) treatment, a common medication for RA. This observation further supports the idea that gut dysbiosis plays a significant role in RA pathogenesis.
Link Between Gum Disease and Rheumatoid Arthritis Risk
Let’s break down the connection between gum disease (periodontitis) and rheumatoid arthritis (RA):
Periodontitis
This is a serious gum infection that damages the soft tissue and bone that support your teeth. If left untreated, it can lead to tooth loss. Think of it as a severe and persistent infection in your gums.
Dysbiosis
Imagine your mouth is like a garden, with a balance of good and bad bacteria. Dysbiosis is like an imbalance in this garden, where the bad bacteria take over, leading to problems like periodontitis.
Citrullination
This is a process where a specific type of protein, called arginine, is modified. Think of it like adding a sticky note to a protein. In the case of RA, this “sticky note” can confuse your immune system, causing it to attack your own joints.
The Connection
Two-Way Street
Having periodontitis increases your risk of developing RA, and people with RA are more likely to get periodontitis. This link is due to shared genetic and environmental factors (like smoking). Both conditions involve chronic inflammation and damage to tissues and bone.
A Key Bacteria
A bacteria called Porphyromonas gingivalis (P. gingivalis), a major cause of periodontitis, plays a significant role in RA. It has a special tool (PAD enzyme) that can modify proteins (citrullination), triggering the immune system to attack the joints. Another bacteria linked to periodontitis, Aggregatibacter actinomycetemcomitans, can also contribute to RA through different mechanisms.
Evidence from Studies
Many studies reported a link between periodontitis and RA, with similar patterns of citrullination in gums and joints, and higher levels of antibodies (ACPA) in people with periodontitis. There are also more antibodies against P. gingivalis in people at risk for RA or living with RA.
Even Apparently Healthy Gums Can Harbor Danger
Studies have found that even in people with seemingly healthy gums, an imbalance of bacteria, including P. gingivalis, can be present in those at risk for RA.
Other Infectious potential Triggers of Rheumatoid Arthritis (RA)
For decades, external infectious agents have been studied as potential risk factors for RA. Several mechanisms have been proposed, including molecular mimicry, where foreign antigens resemble the body’s own proteins, and epitope spreading, where immune responses broaden to include additional targets.
Studies have shown a higher prevalence of antibodies against certain microbes in RA patients and identified bacterial/viral components in joint tissues. Some of the commonly investigated agents include Epstein-Barr virus (EBV), cytomegalovirus (CMV), parvovirus B19, and various bacteria. A high quality systematic review of 48 studies concluded that only parvovirus B19, hepatitis C virus and possibly EBV were associated with RA, while hepatitis B, CMV or other viruses were not associated with RA.
However, some infections such as parvovirus B19 and Lyme disease can cause RA-like symptoms in the acute phase or even generate autoantibodies, making it sometimes difficult to establish a clear link.
Taking all the available body of research into account, it is more likely than not that many infections play a role in developing RA through disturbing the immune system mechanisms, particularly for those who are genetically predisposed.
The Low Down
So, as you can tell by now, RA is tricky! It’s not just about bad luck or “it runs in my family.” While genetics do play a role, it’s really the environment and how we live that often flips the switch, turning that genetic predisposition into actual RA.
Think of it like this: you might have the blueprint for a house, but if the construction crew uses faulty materials or builds in a flood zone, you’re going to have problems. That’s what happens with RA. We’re trying to build a healthy body, but certain things in our lives can disrupt that process.
So, what can we do? Let’s break it down into simple steps, because small changes can make a big difference.
Clean Up Your Environment
Imagine your body is a garden so we need to keep the weeds out. That means minimizing exposure to toxins. Think about using a water filter to remove heavy metals and chemicals, and if you smoke, or are around smokers, please stop as you’re drastically increasing your risk!
Fuel Your Body Right
Let’s focus on whole, nourishing foods; a diet rich in plants, fruits, vegetables, and fish can really support your immune system. Think of it as giving your body the best building blocks, and if organic is accessible and affordable, great! But don’t stress if it’s not. The focus is on a healthy, balanced diet.
Move Your Body
Regular exercise isn’t just about weight loss; it’s about keeping your joints and immune system strong. Even a daily walk can make a difference.
Sunshine and Vitamin D
Vitamin D is like sunshine in a bottle, and many of us don’t get enough. A little sun exposure, combined with vitamin D-rich foods or supplements, can be really helpful.
Gut and Oral Health
Did you know your gut and mouth health are connected to your immune system? Eating fiber-rich foods and practicing good oral hygiene can make a significant impact.
Temperature Control
If you work in a cold environment, bundle up! And if it’s hot outside, don’t turn your indoor environment into a fridge, keep the AC at a comfortable room temperature.
Workplace Safety
If your job exposes you to harmful chemicals, please, please, wear the protective gear provided, and if you believe that there are areas at work that needs improving to minimize your risk, then don’t hesitate to talk to your employer. There are many laws in place to provide you with the protection you need, its often the matter of imposing these laws.
Pesticide Awareness
We’re exposed to pesticides more than we realize. Wash your fruits and vegetables thoroughly, and again, if organic is an option, consider it.
Infection Control
Of course, we can’t live in a bubble, but we can be smart about avoiding infections. Wash your hands, practice good hygiene, and listen to your body.
Ultimately, it’s about making informed choices and taking control of what we can. We’re in this together, and by making these lifestyle adjustments, we can significantly reduce your risk of developing RA and build a healthier future.