What is OI?

Osteogenesis imperfecta (OI) is a genetic disorder characterized by bones that break easily, often from little or no apparent trauma. OI is highly variable and signs and symptoms range from mild to severe. In addition to fractures, people with OI sometimes have muscle weakness or joint laxity and they often have skeletal deformities including short stature, scoliosis and bowing of long bones. A classification system featuring four OI types is commonly used to help define how severely a person with OI is affected. OI occurs with equal frequency in males and females and among all ethnic and racial groups.

The underlying problem causing nearly all instances of OI is a defect in Type 1 collagen, the major structural protein in bones and other connective tissues. In people with OI, either the quantity or the quality of collagen is abnormal, resulting in bones that are less dense and break easily.

What is Osteoporosis?

Osteoporosis is a condition in which the bones become less dense and more likely to fracture. It is primarily a disorder of bone quantity rather than quality. Fractures from osteoporosis can result in significant pain and disability. It is a major health threat for an estimated 44 million Americans, 68% of whom are women.

Risk factors for developing osteoporosis include: thinness or a small body frame; family history of the disease; being postmenopausal or having had early menopause; cessation of menstrual periods; prolonged use of certain medication, such as "steroids" like prednisone; poor dietary calcium intake; physical inactivity; smoking; and excessive alcohol intake.

Osteoporosis is a silent disease until a fracture occurs. It can often be prevented. However, if undetected, it can worsen over many years without symptoms. It has been called "a pediatric disease with geriatric consequences," because building healthy bones in one's youth is important to help prevent osteoporosis and fractures later in life.

The OI - Osteoporosis Link

The term osteoporosis describes a magnitude of bone loss that increases the risk of fracture. The term is a general one; not related to any specific cause for the bone loss. In fact, there are many causes of osteoporosis. Almost all persons with OI are "osteoporotic" because most persons with OI do not develop normal bone mass at any age. Women and men with OI can experience additional bone loss, such as age-related bone loss, superimposed on a background of OI. Symptoms of additional bone loss may appear at a younger age than commonly seen in people who do not have OI. When women and men with osteogenesis imperfecta become middle-aged, their possibility of incurring fractures more easily increases due to the combination of abnormal bone structure and factors that are not limited to OI. Such factors as diet, smoking, and decreased activity, as well as decreased levels of protective sex hormones (testosterone, estrogen, etc.) may lead to a return to the fracture cycles they experienced as children.

Osteoporosis Management Strategies

Strategies for prevention and treatment of osteoporosis in people with osteogenesis imperfecta are generally the same as those for people who do not have OI.

Nutrition and Exercise. A diet with appropriate levels of calcium and vitamin D for the person's size is important for healthy bones. Good sources of calcium include low-fat dairy products, and calcium fortified foods and beverages. Supplements can help ensure that the daily calcium requirement is met when there is significant deficiency and urine calcium levels are not elevated.

Vitamin D acts importantly in dietary calcium absorption and bone health. It is normally synthesized in the skin through exposure to sunlight. Vitamin D supplements may be needed if fortified foods are not part of the diet.

Like muscle, bone is living tissue that responds to exercise by becoming stronger. Weight-bearing exercises that work against gravity are best to prevent bone loss. Some examples include walking, stair climbing and dancing. Swimming can also be a beneficial form of exercise if it is feasible, and easily available. The person with OI should only perform exercise that can be done safely and is well tolerated.

Exercise can be challenging for people with OI who must cope with muscle weakness, bone fragility and deformity, joint instability and pain. However, regular exercises in moderation such as walking can help prevent bone loss and provide other health benefits. All adults, including those who spend most of their time in wheelchairs, need to consult with their doctor and a physical therapist about developing an appropriate exercise program.

Healthy Lifestyle. Smoking has a negative effect on all body systems including bones. Alcohol consumption in excess can also negatively affect bone health and predispose to falls and fracture.

Bone Density Test. Bone mineral density (BMD) tests measure bone density in various sites of the body. BMD measurements are often reported in terms of peak bone mass in young adults. However, people with OI, because of short stature, curvature of the spine, past vertebral fractures or the presence of metal rodding, may not be able to get an accurate reading. Because OI is an osteoporotic condition, almost all adults who have OI have low BMD. However, a base-line measurement in early middle age can be an important part of health management for men and women with OI, since that will give them a personal standard to compare to and determine whether their bone density is changing over time or as the result of a treatment.

Medication. There is no cure for osteoporosis. However, there are medications available to prevent bone loss, to increase bone mass and to treat the disease, which seem to be having success with women and men who have OI. Consult with your doctor to determine which medication is right for you. These medications usually require long-term use.

For additional information on osteoporosis visit the NIH~Osteoporosis and Related Bone Diseases National Resource Center's web site at www.osteo.org or call 800-624-2663

For additional information on osteogenesis imperfecta call 800-981-2663.

This information is brought to you by the
NIH Osteoporosis and Related Bone Diseases~National Resource Center (ORBD~NRC)
and the Osteogenesis Imperfecta Foundation

National Institutes of Health
Osteoporosis and Related Bone Diseases
National Resource Center
1232 22nd St., NW
Washington, DC 20037-1292
Tel: 800/624-BONE or 202/223-0344
Fax: 202/293-2356, TYY: 202/466-4315
http://www.osteo.org
E-mail: orbdnrc@nof.org

The National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from the National Institute of Child Health and Human Development, National Institute of Dental and Craniofacial Research, National Institute of Environmental Health Sciences, NIH Office of Research on Women's Health, Office of Women's Health, PHS, and the National Institute on Aging. The Resource Center is operated by the National Osteoporosis Foundation, in collaboration with the Paget Foundation and the Osteogenesis Imperfecta Foundation.