The exact physiological causes of osteoporosis are unknown, but the progress of the disease and risk factors have been established.
Bones, which handle significant pressure as we move about, consist of two parts: the cortical bone, a hard, solid outer layer, and the trabeculae, an inner, spongy structure that contains bone marrow, which makes red blood cells. Osteoporosis causes the spongy structure to break down, leaving larger spaces that make bones more porous and causing them to become brittle.
Bone loss that occurs as part of the aging process is one of the causes of osteoporosis, This is because after the age of 30, the body begins to dissolve more bone cells than it makes new ones, with the process speeding up after age 50. Estrogen helps slow the rate at which bone is lost in women, so when menopause makes estrogen levels drop bone breaks down more rapidly. However, while getting older increases the risk for osteoporosis, particularly after 70, age does not mean a person will automatically develop the disease.
Other risk factors for osteoporosis include:
- Gender – four times as many women are affected as men
- Low weight – thin people with less muscle are more likely to be affected
- Lifestyle choices
- Poor diet with a deficiency in calcium and vitamin D
- Being sedentary
- Excessive caffeine
- Excessive alcohol consumption
- Race – white and Asian women have the highest incidence
- Medications such as long-term use of corticosteroids
- Rheumatoid arthritis, thyroid problems and other disorders
- A family history of osteoporosis
In children, the causes of osteoporosis include a variety of factors. It may arise from health problems such as diabetes mellitus, hyperthyroidism, kidney disease, rheumatoid arthritis and other conditions. Anticonvulsants and immune medications can play a role. Prolonged immobility or just a lack of activity, and nutritional deficiencies are also involved.
When the causes of osteoporosis relate to underlying health problems, it is called secondary osteoporosis.