Ankylosing spondylitis

Causes and Triggers of Ankylosing Spondylitis

Ankylosing spondylitis (AS) is a chronic inflammatory disease, primarily affecting the spine and sacroiliac joints. The exact cause of AS is unknown, but it’s believed to be a result of a combination of genetic and environmental factors. Understanding the causes and triggers of AS is complex due to this interplay of genetic and environmental factors. Ongoing research continues to explore these relationships to better understand the disease and develop more effective treatments. 

That said, recognizing the potential underlying causes and potential triggers of ankylosing spondylitis will help you make well-informed choices about your treatment and management. Understanding what might make your symptoms worse can help in avoiding certain triggers and adopting lifestyle changes that promote well-being.

Whether you’ve been living with AS for a while or are just starting to learn about it, we’ll be unraveling the complexities of the condition and breaking down the different genetic, environmental, and lifestyle factors that may trigger it.

Let’s look at what we know about the factors that may contribute to developing AS, as well as triggers for AS symptoms.

Genetic Factors in Ankylosing Spondylitis

A great deal of research has focused on genetics and AS. It is well established that while our genes don’t determine our destiny, they are major factors in the susceptibility to autoimmune diseases, including AS.

The Role of the HLA-B27 Gene

The most significant genetic link to AS is the human leukocyte antigen B27 (HLA-B27). The HLA-B27 gene is involved in the immune system’s response to potential threats. It helps the body distinguish its own proteins from foreign ones, such as those from viruses or bacteria. However, in individuals with AS, this gene may trigger an abnormal immune response, leading to inflammation in the spine and other joints. (Source)

About 90% of people with AS carry this gene. However, despite the strong association between HLA-B27 and AS, the presence of this gene alone is not sufficient to cause the disease, and not everyone with the HLA-B27 gene develops AS. This suggests that other genetic factors may also be involved. (Source)

Other Associated Genes

Research has also identified other genes associated with AS, including ERAP1 (endoplasmic reticulum aminopeptidase 1), IL23R (interleukin 23 receptor), and several others. These genes are involved in immune system function and inflammatory responses, further highlighting the role of genetics in AS. (Source)

Moreover, studies have shown that individuals with family members who have AS are at a higher risk of developing the disease, indicating a hereditary component. However, the exact mode of inheritance is not fully understood and is likely to be polygenic, meaning that multiple genes contribute to the disease risk. (Source)

Overall, while genetics play a significant role in the development of ankylosing spondylitis, they are just one piece of the puzzle. Environmental factors, lifestyle, and individual health conditions also contribute to the onset and progression of AS.

Environmental and Lifestyle Triggers

Considering environmental and lifestyle triggers in AS is crucial for a holistic understanding of the disease, improving outcomes, and developing effective management and treatment strategies. It’s important to be aware of these factors for several reasons:

  • understanding disease etiology: While genetic factors such as the HLA-B27 gene play significant roles in AS, they don't fully explain its onset. Environmental and lifestyle factors may interact with genetic predispositions, influencing the development and progression of the disease. Understanding these triggers can provide a more comprehensive view of AS etiology.
  • identifying potential triggers: Certain environmental factors, such as infections, may trigger the onset of AS in genetically susceptible individuals. Identifying these triggers can help in understanding the initial mechanisms that lead to the disease's development.
  • managing symptoms: Lifestyle factors, including physical activity, diet, and smoking, can significantly affect the severity of symptoms and the progression of AS. For instance, regular exercise can improve joint flexibility and reduce pain, while smoking has been linked to worse outcomes in AS patients.
  • preventive strategies: Understanding the role of environmental and lifestyle factors can lead to the development of preventive strategies. For example, early intervention could potentially delay or prevent the onset of the disease if you’re at risk because of a family history of AS.
  • personalized treatment approaches: Recognizing the effects of these factors allows for more personalized treatment plans. For instance, your occupation or daily activities might influence your symptom management strategies.
  • improving quality of life: By addressing lifestyle factors, you can improve your overall quality of life with AS. This includes managing stress, which can exacerbate symptoms, and adopting a healthy diet to reduce inflammation.

Environmental Triggers

Environmental and lifestyle triggers play significant roles in the onset and progression of ankylosing spondylitis. While the exact mechanisms are still being researched, several factors have been identified.


Smoking is one such environmental trigger. Studies have shown that smoking can exacerbate the symptoms of AS, leading to more severe disease progression. It is believed that smoking may increase inflammation in the body, which can worsen the symptoms of AS. (Source)


Another environmental factor is infections. Certain types of bacterial or viral infections can trigger an immune response that may lead to the onset of AS in genetically susceptible individuals. This is especially true for those carrying the HLA-B27 gene. (Source)

Trauma and Injury

Physical trauma or injury to the back or joints may also be a trigger for AS, but it’s not fully known whether injury actually causes the condition or just brings attention to affected joints and bones. (Source)

Lifestyle Factors

Moving on to lifestyle factors, poor diet and lack of exercise can contribute to the severity of AS symptoms. Managing these triggers is an essential part of managing AS. 

The Role of Diet

While diet alone cannot cure ankylosing spondylitis, it plays a crucial role in managing the disease, reducing symptoms, and improving overall quality of life. Because individual responses to different foods can vary, it’s beneficial to have a personalized diet plan. A dietitian or nutritional therapy practitioner can help you create a diet plan that suits your individual needs and preferences and addresses the following important points. (Source, Source)

  • reducing inflammation: AS is characterized by chronic inflammation, particularly in the joints and spine. Diets rich in anti-inflammatory foods can help reduce inflammation. Foods high in omega-3 fatty acids (such as fatty fish, flaxseeds, and walnuts), fruits, vegetables, gluten free whole grains, and healthy fats (like olive oil) are known for their anti-inflammatory properties.
  • gut health: There’s increasing evidence linking gut health to inflammatory diseases, including AS. A diet high in fiber (from fruits, vegetables, and gluten free whole grains) can promote a healthy gut microbiome. Probiotic and prebiotic foods can also support gut health, potentially affecting inflammation and immune function.
  • avoiding trigger foods: You may find that certain foods exacerbate your AS symptoms. Common triggers include high-fat and high-sugar foods, gluten, and dairy. Identifying and avoiding personal trigger foods can help in managing symptoms.
  • bone health: Ankylosing spondylitis can increase the risk of osteoporosis. A diet rich in calcium and vitamin D is important to maintain bone health. This includes dairy products, fortified foods, leafy green vegetables, and adequate sunlight exposure.
  • energy level: Fatigue is a common symptom in AS. Eating regular meals and snacks with a good balance of carbohydrates, proteins, and fats can help maintain steady energy levels throughout the day.
  • heart health: Having AS may put you at a higher risk of cardiovascular disease. A heart-healthy diet, low in saturated fats and high in fruits, vegetables, and whole grains, is recommended.
  • supplements: Even if you follow the healthiest diet you can, you may benefit from dietary supplements such as omega-3 fatty acids, turmeric, or vitamin D. However, supplements may cause unwanted side effects or interfere with medications you may be taking, so be sure to consult with your health care provider or care team before starting any new ones.

Exercise Is Essential

Exercise is a vital component in managing ankylosing spondylitis. Regular, moderate exercise is generally recommended over sporadic, high-intensity workouts to manage AS effectively. The benefits of exercise in managing AS are numerous. (Source, Source)

  • flexibility: For example, regular physical activity helps improve flexibility and posture, crucial for combating the rigidity associated with AS. Stretching exercises are particularly beneficial, aiding in maintaining spinal mobility and preventing the development of a hunched posture.
  • pain relief: Exercise plays a significant role in alleviating pain and stiffness. Increased blood flow from physical activity can reduce inflammation, while strengthening exercises build muscle around affected joints, providing better support and reducing strain. This muscle strengthening not only eases joint stress but also enhances overall stability and balance, crucial for daily functioning.
  • cardiovascular health: Aerobic exercises such as walking, swimming, or cycling are especially important, as they bolster cardiovascular health and aid in weight management. People with AS have an elevated risk of cardiovascular diseases, and maintaining a healthy weight is essential to reduce additional joint strain. 
  • bone and respiratory health: Furthermore, weight-bearing exercises, such as walking and resistance training, are key in promoting bone health and preventing osteoporosis, a common concern in AS. Exercise also has substantial benefits for respiratory function, particularly vital if AS affects the ribcage and lung capacity.
  • mental health: Beyond the physical benefits, regular exercise can significantly improve mental health and quality of life. It can alleviate symptoms of depression and anxiety, common in chronic conditions, through the release of endorphins. Improved sleep quality is another crucial benefit, as good sleep helps manage pain and fatigue associated with AS. 

To make sure activities are tailored to your specific needs and limitations, it’s important to consult with your health care provider or care team before starting any exercise regimen. 

Stress Takes a Toll

Stress plays a significant role in the management of AS. Chronic stress, a common experience in those living with chronic illnesses, can have a direct effect on AS symptoms. The body’s stress response, often characterized by the release of hormones such as cortisol, can lead to increased inflammation. This heightened inflammatory response can exacerbate the symptoms of AS, such as joint pain and stiffness, and can potentially accelerate the progression of the disease. Moreover, stress can also disrupt sleep patterns and overall quality of life, making effective management of AS more challenging. (Source)

Incorporating stress management techniques into your daily routine can be highly beneficial. Mindfulness practices, yoga, and meditation are particularly effective in mitigating stress. 

  • Mindfulness encourages a state of active, open attention to the present, which can help in recognizing and managing stress triggers.
  • Yoga, combining physical postures with breathing exercises, not only aids in reducing stress but also improves flexibility and strength, which are vital for people with AS.
  • Meditation, through its focus on deep breathing and relaxation, can lower stress levels, reduce inflammation, and improve pain management.

These practices not only help in managing the physical symptoms of AS but also enhance mental health, providing a holistic approach to dealing with the condition. Engaging in these activities regularly can lead to significant improvements in managing AS symptoms, overall health, and quality of life.

Sleep and AS

Quality sleep is essential for the body’s recovery and regulation of various biological processes, including the inflammatory responses associated with AS. When sleep is compromised, either in duration or quality, it can have a direct effect on the severity of AS symptoms. Lack of restful sleep often leads to increased pain sensitivity and heightened perception of discomfort, common issues in AS. Additionally, fatigue, another prevalent symptom of AS, is significantly worsened by poor sleep. This can create a vicious cycle where pain disrupts sleep, and the resultant lack of sleep further aggravates pain and fatigue, affecting daily functioning and overall quality of life. (Source)

Good sleep hygiene involves creating and adhering to routines and environmental factors conducive to restful sleep. This includes: 

  • establishing a regular sleep schedule
  • creating a comfortable and sleep-friendly environment (such as a dark, quiet, and cool bedroom)
  • avoiding stimulants such as caffeine and electronics before bedtime

Relaxation techniques such as gentle stretching, deep breathing exercises, or listening to calming music can also aid in preparing your body and mind for sleep. Prioritizing sleep hygiene can significantly improve sleep quality, thereby helping to manage pain and fatigue associated with ankylosing spondylitis more effectively.

Immune System’s Role in AS

Autoimmunity and Inflammation

Inflammation plays a central role in the manifestation of symptoms in ankylosing spondylitis — in fact, “spondylitis” means inflammation of the vertebrae. AS symptoms are primarily a result of the body’s immune response causing inflammation in the affected areas, particularly the spine. (Source)

In the case of AS, the immune system mistakenly targets the joints in the spine, leading to inflammation. This inflammation can cause pain and stiffness, which are common symptoms of the condition. The inflammation can also lead to the formation of new bone in the spine, which can cause further stiffness and reduced flexibility.

Moreover, inflammation in AS is not just confined to the spine. It can also affect other parts of the body, including the eyes, skin, and bowels, leading to a range of other symptoms. For instance, inflammation of the eye, known as uveitis, can cause redness and pain. Inflammation of the skin can lead to psoriasis, and inflammation of the bowels can lead to symptoms of inflammatory bowel disease.

Understanding the role of inflammation in AS is crucial for its management. Many of the current treatments for AS, such as non-steroidal anti-inflammatory drugs (NSAIDs) and TNF inhibitors, work by reducing inflammation and thereby alleviating symptoms. Therefore, managing inflammation is a key strategy in controlling the symptoms of AS. (Source)

Proinflammatory Cytokines

Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-17 (IL-17), are key players in the inflammation process in AS. These cytokines are proteins that regulate the body’s immune response, and their overproduction can lead to increased inflammation and subsequent symptom manifestation. (Source)

T Cell Repertoire and Immune Response

T cell expansion is the process by which T cells, white blood cells that play a central role in the immune response, increase in number in response to specific triggers, such as the presence of a pathogen or an antigen. This process is crucial for the immune system’s ability to fight infections and diseases. However, the expansion of CD8+ T cells in particular has been observed in those with ankylosing spondylitis, and studies have shown that these cells may be involved in the inflammatory processes that characterize the disease. (Source)

Interestingly, the expansion of these CD8+ T cells seems to be correlated with disease activity in AS. Some studies have shown that the frequency of these cells decreases with effective treatment, suggesting they could potentially be used as a biomarker for disease activity. (Source)

However, while these findings provide valuable insights into the role of T cells in AS, it’s important to note that the precise mechanisms through which these cells contribute to the disease are still not fully understood. Further research is needed to clarify their role and to explore potential therapeutic strategies targeting these cells.

The Bottom Line

Ankylosing spondylitis is a form of arthritis primarily affecting the spine, leading to chronic pain and stiffness. The HLA-B27 gene is strongly linked to AS, but not everyone with this gene develops the condition. Environmental factors may also influence the development or worsening of AS. Understanding the genetic, environmental, and immunological aspects of AS is essential for effective treatment. With advancements in medical research and a holistic approach to care, you can live a fulfilling life with AS.

At WellTheory, we’re committed to supporting you on your AS journey, recognizing that your health is deeply personal to you and requires personalized advice, guidance, and strategies tailored to your unique situation. Our expertise in autoimmune disease care means we’re well-equipped to offer insights, advice, and resources that cater to your needs. Together, we can navigate the complexities of ankylosing spondylitis, ensuring you’re not just informed, but also empowered to make the best decisions for your health.


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