Epidemiology
Three males are diagnosed with AS for every one female; the overall prevalence is 0.25%. Many rheumatologists believe the number of women with AS is underdiagnosed, as most women tend to experience milder symptoms. The majority of patients with AS exhibit the HLA-B27 antigen and high levels of immunoglobulin A (IgA) in the blood. The HLA-B27 antigen is also expressed by Klebsiella bacteria, which are found in high levels in the feces of AS patients. A theory suggests the presence of the bacteria may be a trigger of the disease, and reducing the amount of starch in the diet (which these bacteria require to grow) may be of benefit to AS patients. A test of this diet resulted in reduced symptoms and inflammation in patients with AS as well as IgA levels in individuals with and without AS. Further research is required to determine if diet changes may have a clinical effect on the course of the disease.
Read more about this topic: Ankylosing Spondylitis