Which pathology is characterized by mid-low back pain lasting about 3 months and onset before age 40, more common in men?

Ankylosing spondylitis is a type of inflammatory arthritis that primarily affects the spine and sacroiliac joints in the pelvis. It typically presents with mid to low back pain that persists for at least three months, and it often starts before the age of 40. The pain is commonly worse during periods of inactivity, such as at night or in the morning, and may improve with movement.

A significant characteristic of ankylosing spondylitis is its predominance in men, with a higher incidence compared to women. The condition can lead to progressive spinal stiffness and other complications if left untreated. The diagnosis is often supported by clinical findings of inflammatory back pain, physical examination, and imaging studies showing changes in the sacroiliac joints.

The other options listed do not fit this specific clinical presentation as well as ankylosing spondylitis does. Osteoarthritis typically manifests with pain that worsens with activity and is associated with older age. Rheumatoid arthritis usually presents with systemic symptoms and is characterized by symmetrical joint involvement, often affecting smaller joints first. Degenerative disk disease tends to cause more localized pain without the specific inflammatory features seen in ankylosing spondylitis. Overall, the combination of early onset, long