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What is Spondylitis?

Spondylitis is the name given to a group of chronic or long lasting diseases. Spondylitis is an ‘inflammation of the vertebra’ and ‘ankylosis’ refers to joint fusion or immobility.

This group of diseases primarily affects the spine (spondylo) and other joints. The group includes: ankylosing spondylitis, reacti
ve arthritis, psoriatic arthritis,
Juvenile SpA, enteropathic arthritis (spondylitis/arthritis associated with inflammatory bowel disease), and undifferentiated SpA.

They display a variety of symptoms and signs including:

  • A condition called enthesopathy, which is an inflammation where the ligaments attach to the bone
  • A tendency to occur in more than one family member
  • The absence of physical signs or testing markers that are found in other types of arthritis, such as sub-cutaneous nodules (or lumps under the skin) and a positive blood test for the rheumatoid factor

The complete medical term for this group of diseases is the ‘seronegative spondyloarthritis’. ‘Sero’ refers to blood (blood serum) and ‘negative’ indicates that there is usually no rheumatoid factor present in the blood.

Most types of SpA begin around the ages of 15-45. Most people with spondylitis lead long and productive lives. Certain complications, however, can lead to disability. It is important to be on the lookout for signs and symptoms of the more serious complications.

It is important to note that back pain and joint pain from ankylosing spondylitis and related diseases is inflammatory in nature and not mechanical.

The Prevalence of Spondylitis

Just how common is spondyloarthritis globally? Is it more common in certain parts of the world and populations than others? And are we close to being able to estimate the number of people worldwide who have spondyloarthritis?

To investigate these questions, Dutch researchers conducted a literature review, analyzing 30 spondyloarthritis prevalence studies from different parts of the world, spanning nearly four decades (from 1975 to 2014.) “This study is the first to pool global estimated prevalence of spondyloarthritis in the general population and to investigate demographic and methodologic characteristics influencing them,” write the authors in Arthritis Care & Research.

Results: The researchers found that prevalence of spondyloarthritis varied greatly across the world, ranging from 0.20% in South-East Asian populations to a high of 1.61% in Northern Arctic communities. The geographic clustering of spondyloarthritis is likely related to the genetic characteristics of populations, notably HLA-B27 positivity – which is strongly linked to spondyloarthritis.

The researchers also attempted to find specific prevalence numbers for each of the subgroups in spondyloarthritis, but were only able to conduct a meta-analysis for ankylosing spondylitis (AS) and psoriatic arthritis (PsA). The prevalence of AS ranged from a low of 0.02% in Sub-Saharan Africa, to 0.35% in the Northern Arctic. The prevalence of PsA ranged from 0.01% in the Middle East to 0.19% in Europe. The authors reported having too few studies available on other spondyloarthritis subgroups to conduct meta-analyses.

So can we glean a global spondyloarthritis prevalence estimate from these findings? The short answer is “no, not yet.” As we don’t have complete and reliable prevalence numbers for many parts of the world, it is difficult, if not impossible, to estimate with a reasonable level of accuracy just how many people may have spondyloarthritis worldwide.

In fact, it was only in 2012 that the CDC provided the US national prevalence estimates for axial spondyloarthritis, finding that it may affect up to 1% of US adults, or an estimated 2.7 million persons.

“High quality studies are needed to estimate the prevalence of spondyloarthritis in the general population…” say the authors. A reliable world prevalence estimate will only be possible when we have accurate and robust reporting from all regions of the world.


More Information

Although there is currently no known cure, there is much you can do to educate yourself regarding spondylitis and its treatments. There have been significant advancements in medical treatments during recent years and there are treatment options for those afflicted that can reduce the pain and symptoms of ankylosing spondylitis and related diseases.

Spondyloarthritis: A Family of Related Diseases