Is it true that African Americans are less likely than white Americans to need a hip replacement? I heard that on a radio news report. Or are those figures lower for African Americans because of the socioeconomic differences (no insurance, no health care)?
It was recently reported that hip replacements due to primary osteoarthritis are less likely among American Hispanics and African Americans compared with whites of European ancestry. People of European descent are the only ones who develop primary osteoarthritis (OA) of the hip.
You heard correctly that individuals who are of African or Asian lineage are much less likely to develop this condition. In fact, according to current research, primary osteoarthritis is completely absent in true Asian and African people. Only those adults who are a mixture of African (or Asian) and European develop primary OA.
Primary osteoarthritis of the hip refers to loss of joint space from a degenerative process affecting the hip joint cartilage. It only occurs in adults 55 year old or older. It is not caused by previous hip problems in childhood like Perthes disease, trauma, developmental dysplasia, or slipped capital femoral epiphysis (SCFE). Other potential causes for the arthritic changes are also ruled out (e.g., rheumatoid arthritis, Paget disease, sepsis).
Naturally, after making this discovery that there is a difference in rates of hip replacement between Europeans and non-Europeans, the scientists started looking for an environmental or genetic explanation. They used data from family and twin studies to look for factors that might explain the European versus non-European differences in rates of hip osteoarthritis. They did not find any environmental risk factor that could account for these differences. But there were some genetic links.
Putting this finding into statistical terms, here's what they found. Primary hip osteoarthritis is the reason for 65 to 70 per cent of all hip replacements (around the world). And 100 per cent of those hip replacements are in people with European ancestry. Intermarriage among Europeans and Asians or Africans eventually (over 20 generations) results in the same risk for osteoarthritis as among those who are 100% European.
Based on Medicare data for hip replacement surgeries, African Americans account for only half the number of joint replacements. Their ancestry consists of 20 per cent European DNA. American Hispanics with 50 per cent European DNA have up to one-half the rate of hip replacements as European-descent whites.
The lower rate of hip replacement among African Americans may be an indicator of differences in health care by race. Studies show that African Americans have just as much hip osteoarthritis as white (caucasian) Americans. But with only half as many hip replacements, the search is on for why the discrepancy.
There may be an environmental factor but this has not been identified yet. More study is needed to sort through all the possible reasons for these differences. The ultimate goal is to find ways to prevent osteoarthritis -- and in populations with equal disease, provide equal treatment regardless of race or ancestry.
Franklin T. Hoaglund, MD. Primary Osteoarthritis of the Hip: A Genetic Disease Caused by European Genetic Variants. In The Journal of Bone and Joint Surgery. March 6, 2013. Vol. 95A. No. 5. Pp. 463-468.
*Disclaimer:* The information contained herein is compiled from a variety of sources. It may not be complete or timely. It does not cover all diseases, physical conditions, ailments or treatments. The information should NOT be used in place of visit with your healthcare provider, nor should you disregard the advice of your health care provider because of any information you read in this topic.