Ankylosing spondylitis is an ancient, chronic connective tissue disease with significant familial aggregation and a strong association with HLA-B27. Ankylosing spondylitis has a worldwide distribution and is one of the most common diseases of the joints, with population prevalence varying across races and countries. In general, the prevalence is highest in Indians, followed by Caucasians, lower in Yellow than Caucasians, and lowest in Blacks. I. Age
Ankylosing spondylitis can occur at any age, but usually develops between the ages of 10 and 40. 10% to 20% of patients with AS develop the disease before the age of 16, with a peak at the age of 15-35 and an average age of onset of 25, while after the age of 50 it is rare in children under the age of 8. Patients over the age of 40, whether adults or children, are often not taken seriously at the onset because of mild symptoms. Once the symptoms become apparent and the medical history is followed, the disease has actually been present for months or years. According to domestic and international reports, the interval between the initial onset of symptoms and a definitive diagnosis can be delayed by an average of 3 to 4 years. In recent years, due to the emphasis on ankylosing spondylitis and the improvement of diagnosis, a large number of children aged 6 to 10 years have been found to develop the disease, and the age of onset is low.
The trend is towards a younger age. The prevalence of AS in men is generally higher, while the incidence in women is relatively rare.
However, recent studies have found that the difference in the onset of ankylosing spondylitis is not so great between the sexes, except that the onset in women is often slower and less severe, and the clinical presentation is less typical, making it easier to delay the diagnosis or even miss the diagnosis. It is generally accepted that men account for 65% to 80% of patients with ankylosing spondylitis, i.e., the ratio of men to women is about 3:1.
～The clinical manifestations of the disease vary by gender. In men, the spine and pelvis are most commonly involved, and the chest wall, hip, shoulder, and foot can also be involved. In contrast, female patients have a relatively late age of onset and relatively mild spinal lesions, while the knee, wrist, ankle, hip, and pelvis are more frequently involved.