• Ankylosing spondylitis (AS) is a form of arthritis that affects the spine.
  • Most people with AS receive a diagnosis at a young age. Most therefore have the opportunity to participate in treatment.
  • Although AS symptoms can get worse over time, physical therapy and medications can help slow the progression.

Ankylosing spondylitis causes inflammation of the ligaments and joints in your spine. Over time, this can progress from mild back and hip pain to more severe stiffness and pain. It can also affect other joints in your body.

Exercise and medication can help you manage the condition.

Most people with ankylosing spondylitis (AS) receive a diagnosis before age 45 years. The condition starts most often between ages 20 and 40 years, but youth and children may also experience AS onset. It’s diagnosed three times more often in men than in women.

There’s a strong genetic link with ankylosing spondylitis (AS). About 90 percent of white people with AS have the human leukocyte antigen B27 (HLA-B27). However, having HLA-B27 does not necessarily mean you will develop AS. Other genetic markers may also contribute to your chance of an AS diagnosis.

A 2020 study involving people diagnosed with AS in Sweden over a 15-year period cited older research about how family history increases AS risk.

If one identical twin has AS, there’s a 25 to 75 percent chance the other twin will develop it as well. This likelihood is about 4 to 15 percent for non-identical twins. In the study, researchers found a 20-fold increase in the chance of parents, children, and siblings of those with AS also developing the condition.

Since both identical twins don’t always develop AS, genetics may not be the only factor. Environmental factors likely play a role as well.

People with AS are initially diagnosed with a condition called non-radiographic axial spondyloarthritis (nr-axSpA). This is a form of arthritis caused by spinal inflammation.

With nr-axSpA, you can have the signs and symptoms of spinal inflammation, but X-rays do not show any damage to the sacroiliac joints, joining your spine and your pelvis, but changes are seen on MRI. When damage to your sacroiliac joints become visible on an X-ray, the disease has progressed.

Not everyone who has nr-axSpA will develop AS. For those who do, the progression may be quite slow. Research from 2018 estimated that 5.1 percent of people will experience this progression within 5 years and 19 percent within 10 years.

For those who have AS, the tendons and ligaments that attach to bone become chronically inflamed. Over time, this can lead to the development of scar tissue and extra bone. You may experience physical changes, like reduced mobility, as a result.

Researchers still don’t know for sure who will develop AS, even among people with nr-axSpA. However, there are some predictive factors. Those include the presence of syndesmophytes, which are calcifications in ligaments connecting vertebral bodies of the spine.

Another 2018 study found having obesity was a predictor for men and women. Smoking was a greater predictor in men. Exposure to a group of drugs called bisphosphonates were a greater predictor in women.

People with AS are at a greater risk for developing certain other health conditions. Some of the potential complications of AS include:

  • osteoporosis
  • spinal fractures
  • iritis (eye condition that can result in vision loss)
  • cauda equina syndrome (compression of nerves at the bottom of the spine)
  • amyloidosis (buildup of a type of protein in the organs like heart, kidneys, and liver)
  • cardiovascular disease
  • fibromyalgia

A 2015 study found the incidence of cardiovascular disease among a group of people with AS was three times higher than predicted by standard cardiovascular risk measurements.

Research from 2021 found people of all ages with AS had a higher chance of developing fibromyalgia, but it was particularly higher for those over age 65 years.

There are a number of treatments for ankylosing spondylitis. These treatments can help slow the progression of the condition and may help repair joint damage.

  • Medication, to reduce inflammation and relieve pain. Common medications for AS include:
    • nonsteroidal anti-inflammatory drugs (NSAIDs)
    • biologics, which work on the immune system
    • corticosteroid injections into the joints
  • Physical therapy and exercise, to strengthen back, neck, and abdominal muscles and to relieve pain. Exercise can also help maintain posture and improve joint flexibility.
  • Surgery, to restore joint function. This may apply specifically to the hip joint.

The goal of treatment is to help maintain flexibility and reduce pain. Your doctors may begin with anti-inflammatory medications and then move to other medications if necessary. Among the biologics they may prescribe for AS are tumor necrosis factor inhibitors such as:

  • adalimumab (Humira)
  • infliximab (Remicade, Inflectra)
  • etanercept (Enbrel)

Since many of the signs and symptoms of AS are caused by inflammation, reducing that inflammation may result in a slower progression and prevent loss of mobility.

Ankylosing spondylitis (AS) is a form of inflammatory arthritis. It develops from a condition called non-radiographic axial spondyloarthritis (nr-axSpA), where the symptoms of arthritis are present, but no joint damage is visible on an X-ray. Progression to AS can happen over many years.

While AS can get worse as you naturally age, actively engaging in physical therapy and exercise can help reduce pain and maintain flexibility. In addition, over-the-counter and prescription medications can help reduce inflammation that worsens the symptoms of AS.