Osteoporosis among African Americans studied
by Walter Brooks, UNMC public affairs

The old adage that "sticks and stones may break my bones, but names will never hurt me" was coined long before African Americans became aware of the word "osteoporosis." But the first studies published on low bone density and fracture-related outcomes among African American patients indicate that osteoporosis is not only a painful word, it can be debilitating - even lethal - and at a rate far out of proportion to outcomes for Caucasians.

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Ted Mikuls, M.D.
Ted Mikuls, M.D., M.S.P.H., assistant professor in rheumatology and immunology at UNMC, is primary investigator and co-author of two studies published on osteoporosis among African Americans in the June 2005 Journal of Rheumatology and the August 2005 Journal of the National Medical Association.

Osteoporosis is a disease in which bones become fragile and more likely to break. If not prevented or if left untreated, osteoporosis can progress painlessly until a bone breaks. These broken bones, also known as fractures, occur typically in the hip, spine and wrist. Any bone can be affected, but of special concern are fractures of the hip and spine. A hip fracture almost always requires hospitalization and major surgery. It can impair a person's ability to walk unassisted and may cause prolonged or permanent disability or even death. Spinal or vertebral fractures also have serious consequences, including loss of height, severe back pain and deformity.

"Although the incidence of osteoporosis is lower in African Americans than in Caucasians, African Americans have substantially worse fracture-related outcomes," Dr. Mikuls said. "Fractures occurring in African American women result in increased disability, longer hospital stays and higher overall mortality, underscoring the importance of racial disparities that occur in osteoporosis care."

In a recent study examining racial/ethnic disparities in osteoporosis care among community-dwelling older women with arthritis, Dr. Mikuls and his collaborators from the University of Alabama at Birmingham found that African American women were substantially less likely than older Caucasian women to receive bone mineral density (BMD) testing or prescription osteoporosis treatments, even after adjusting for known osteoporosis risk factors.

Patients were eligible to participate in the study if they self-reported arthritis and were over 50 years of age. Arthritis was defined as the presence of joint symptoms lasting most days for at least one month out of the previous 12 months or by a history of an appropriate physician diagnosis. The Caucasian women had a mean age of 68. The African American women with a history of fracture were slightly younger, but the fracture types - wrist, ribs, spine and hip - were similar among both categories of women.

"The study did not collect comprehensive date regarding the association of excessive trauma with reported fractures," Dr. Mikuls said. "However, most fractures result directly from some traumatic event and for any given fracture, it is impossible to know whether it happened primarily due to insufficient bone strength or excessive skeletal loading. This uncertainty emphasizes the importance of obtaining bone mineral density examinations."

Bone density tests are currently the most practical way to accurately measure bone strength and overall fracture risk. The test requires using a DPX bone densitometer (DEXA), an exceptional tool for diagnosing and managing low bone density. When tests are repeated over time, they can help the physician track the rate of bone loss. In addition, the study results indicated that rheumatologists were more likely than general practitioners and other types of specialists to prescribe treatments for osteoporosis care.

"There are very effective medicines available - bisphosphanates - that substantially decrease the risk of future fractures and slow down bone loss in those at risk," Dr. Mikuls said. "In addition, calcium and vitamin D are still valuable nutrients in bone density development. Minor traumas that lead to a fall or a fracture should always trigger a concern for fracture risk and osteoporosis and consideration should be given to obtaining a formal bone density assessment. On the other hand, we also know that the major DEXA manufacturers define osteoporosis differently in African Americans, making fracture risk assessment in this group especially challenging."

In a recent study, Dr. Mikuls and colleagues found that African Americans with rheumatoid arthritis were at substantial risk of receiving different diagnoses based simply on the type of DEXA machine used for the bone density assessment.

"We definitely need more studies to learn how to best predict fracture risk among non-Caucasians and in the meantime we need to adopt a more standardized approach to evaluating African Americans with risk factors for osteoporosis," Dr. Mikuls said.

Dr. Mikuls noted that it is unknown whether African Americans have a different fracture threshold than Caucasians, or whether fracture risk is a function of absolute bone density independent of race/ethnicity.

"To our knowledge, this is the first study to systematically examine the prevalence of low bone density in African American patients with rheumatoid arthritis," Dr. Mikuls said.

"There is no accepted standard regarding the best approach to the diagnosis of osteoporosis in non-Caucasians. But the proven effectiveness of bisphosphonate therapy in African Americans, coupled with the fact that such fractures lead to disproportionately poor outcomes among minorities, underscores the importance of accurate risk assessment of this population."

Date Published: Tuesday, August 23, 2005