How common is ankylosing spondylitis, and what causes this inflammatory condition?

Ankylosing spondylitis (AS) is a relatively uncommon type of inflammatory arthritis that affects the joints in the lumbar spine, including the sacroiliac (SI) joint in the pelvic region. This complex condition is almost as prevalent as rheumatoid arthritis, occurring in approximately 0.35 to 1.3 percent of the population.

What causes ankylosing spondylitis?

The causes of ankylosing spondylitis are not yet well understood. Some studies suggest that there may be a hereditary link to a gene known as HLA-B27. However, the presence of this gene does not definitively mean that an individual will develop AS. By the same token, some people who are diagnosed with this condition do not carry the HLA-B27 gene. For these reasons, scientists believe that other factors may trigger the development of ankylosing spondylitis in people with or without an inherited tendency. As of yet, these specific triggers have not been identified.

What are the signs of ankylosing spondylitis?

Initially, ankylosing spondylitis causes spinal joint inflammation, which can result in severe pain and stiffness. Then, as the inflammation progresses, new bony tissue can develop on the spinal bones, causing the vertebrae to fuse together (ankylosis). This can lead to a gradual loss of flexibility and mobility as the spine takes on an exaggerated, hunched-forward posture.

The first sign of AS is usually a mild backache that intensifies gradually over several months. Typically, the discomfort is worse upon waking in the morning, then eases with movement and physical activity. Ankylosing spondylitis has also been linked to a heightened risk of developing other medical conditions, including ulcerative colitis, Crohn’s disease, psoriasis, osteoporosis and cardiovascular disease.

In many cases, AS is diagnosed in early adulthood (between age 20 and 30), but the condition sometimes develops in children and older adults as well. For unknown reasons, AS occurs more often in men than in women.

Finding relief after a diagnosis

While Laser Spine Institute does not treat ankylosing spondylitis, our dedicated team helps patients who have been diagnosed with this condition find appropriate treatment options. For instance, we may be able to help you find a conservative or surgical approach to help relieve some of the associated pain and stiffness.