Causes of Axial Spondyloarthritis

Axial spondyloarthritis, or axSpA, is a disease that causes inflammation, primarily in the axial spine and sacroiliac joints, located where the bottom of your spine attaches to your pelvis. As a result, the earliest symptoms of this condition are typically back pain and stiffness. While the exact cause of axial spondyloarthritis is not known, there are risk factors that contribute to this condition.

This article discusses genetics and other risk factors, such as age, body composition, sex, and lifestyle habits, that can play a role in axial spondyloarthritis.

Common Causes

Axial spondyloarthritis is an inflammatory autoimmune disease. In autoimmune diseases, your body's immune system mistakenly attacks its own structures, such as joints and muscles.

The exact cause of autoimmune conditions is not known. They are sometimes thought to be triggered by bacteria, viruses, or medication that the body mistakenly views as "foreign."

There are no known common causes of axial spondyloarthritis. However, there are a few risk factors that can contribute to the development of this disease.

Unmodifiable Risk Factors

While researchers haven't discovered a definitive cause of axSpA, they have identified unmodifiable risk factors that may contribute to its development. These include genetics and the presence of conditions such as inflammatory bowel diseases and osteoporosis, sex, and age.

Genetics

Researchers have found that genetics plays a role in the development of axial spondyloarthritis. The HLA-B27 gene tells your body how to make specific proteins that help your immune system tell the difference between its own cells and foreign substances.

A specific protein that is also called HLA-B27 is found on the surface of your cells when your body is fighting infection. If HLA-B27 is present in your blood, you might have an autoimmune disorder.

Ankylosing spondylitis, the most common type of axial spondyloarthritis, is linked to the HLA-B27 protein. However, not all people with this protein will have an autoimmune disorder.

Other Medical Conditions

Gut inflammation and joint inflammation often occur together. Although digestive conditions don't cause axial spondyloarthritis, researchers have found that people with this diagnosis often also have inflammatory bowel diseases, such as Crohn's disease or ulcerative colitis.

Osteoporosis is a condition that causes bones to become thin and brittle. Many people with axSpA also have osteoporosis. Although osteoporosis is more common in postmenopausal women, men with axial spondyloarthritis also often have low bone mass densities. The combination of conditions can cause bones in the spine to collapse and can lead to broken bones elsewhere in the body.

Sex and Age

Historically, axial spondyloarthritis was thought to affect more males than females. However, researchers now believe that males are more frequently diagnosed with this condition because it is often overlooked or misdiagnosed in females.

In men, axial spondyloarthritis often causes inflammatory back pain, with bone issues that show up on X-rays at an earlier stage in the disease process. Women with axial spondyloarthritis often experience widespread pain throughout the body, which can initially lead to a wrong diagnosis of other pain-related conditions, such as fibromyalgia.

Age

Age plays a role in axial spondyloarthritis. Unlike other types of arthritis, this condition shows up much earlier in life—sometimes during the teenage years and almost always before the age of 45.

Lifestyle (Modifiable) Risk Factors

While lifestyle choices won't directly cause axial spondyloarthritis, they can significantly impact how severe your symptoms are. These factors are modifiable, meaning you can change them. That doesn't mean it's easy to change them, but it is possible.

Smoking

One potential risk factor associated with this condition is smoking.

Research has shown that smoking can increase disease activity, which means smoking can make the symptoms of axSpA worse. Smoking is also linked to increased stiffness in the joints affected by the disease, as well as a higher chance that young people with this condition will develop back pain at an earlier age.

Obesity

Obesity is very common in people with axial spondyloarthritis. While it doesn't directly cause arthritis, extra body weight makes the symptoms of this condition—back pain and stiffness—more severe.

Physical Activity Levels

High levels of physical activity, causing wear and tear on the body, might also contribute to axial spondyloarthritis. This condition specifically causes enthesitis, which is inflammation of the enthesis, the connective tissue where tendons (connecting muscles to bone) and ligaments (connecting bone to bone) are attached to the bone.

Summary

Axial spondyloarthritis is an autoimmune disorder that typically develops before a person reaches middle age. Early symptoms include back pain and stiffness. The exact cause of this condition is not known, but risk factors include genetics, other medical conditions, and lifestyle factors, such as smoking.

A Word From Verywell

Axial spondyloarthritis can cause symptoms that interfere with your ability to perform daily tasks. While you can't prevent the condition from occurring, you can control some of the risk factors that can make your symptoms worse—such as by not smoking and by exercising safely.

Ask your healthcare provider for advice on making positive lifestyle changes to improve your quality of life. A support group may offer additional encouragement and community, if needed.