Osteoporosis
Spondyloarthritis may affect the structure and strength of bones, making them prone to break under stress.
Very often, MRIs from SpA patients show minimal inflammation in the joint but striking inflammation in the bone next to the joint. This inflammation is also typically seen where ligaments and tendons attach to the bone (enthesitis). If this local inflammation in the spine is not controlled, it will ultimately result in fragile spinal bones.
There is also a second way people with SpA can develop fragile bones. Systemic inflammation causes the release of certain chemicals into the blood that activate cells in bone that can dissolve bone mineral. These cells are called osteoclasts, and secrete acid, which dissolves bone.
As a result, people with SpA suffer from a one-two punch when it comes to bone health. They have inflammation locally within the bones of the spine, but also systemic inflammation contributing to weakening of bones. This is one reason why those with AS are at much higher risk of spinal fractures.
To make matters worse, fusion in the spine, which occurs in some with AS, makes the spine rigid and inflexible, making it more likely to fracture if subjected to any significant impact.
For women with SpA, menopause is an especially precarious period, as the rapid decrease in sex hormone production also results in the activation of osteoclasts.
What can be done about this? First, those with SpA should make sure they stay active, not only to preserve strength and flexibility, but also to preserve bone mineral. The cells that make bone mineral love weight-bearing exercise. But they can only do their work properly if they are supplied with the proper nutrients. This means plenty of vitamin D and calcium each day.
Doctors prefer calcium that is sourced through nutrition, and the recommended amount depends on your age, bone health, and risk factors for osteoporosis. A good rule of thumb is that one good helping of a dairy product – yogurt, cheese, a tall glass of skim milk – provides 300mg of elemental calcium. Other calcium-rich foods include collard greens, and fortified cereals. Doctors also recommend screening for vitamin D deficiency, and consuming the recommended amount of vitamin D daily. Vitamin D is found in foods such as salmon, swordfish, cod liver oil, and fortified foods and beverages. Exposure to sunlight is another source. Numerous vitamin D supplements are also available.
There are several medications available for the treatment of osteoporosis, should you and your doctor determine that they are needed. These include agents belonging to a general class of drugs called bisphosphonates. Biologic medications have also been shown to increase bone density, likely by suppressing inflammation.
