Total hip replacement rates are higher among Caucasians than Asians in Hawaii.

The etiology of hip osteoarthritis remains unknown but may involve genetic or lifestyle factors. Most cases of total hip replacement are performed because of osteoarthritis. To examine possible ethnic differences, hospital records in Hawaii from 1985 to 1989 were reviewed. Preoperative radiographs were reviewed for a subset of patients to ascertain the reason for total hip replacement. Osteoarthritis accounted for a greater percentage of total hip replacements among whites (59% for women and 66% for men) than among Japanese (36% of women and 30% of men). The incidence of total hip replacement for whites was three to 25 times greater than that of other ethnic groups (Japanese, Chinese, Filipino, and Hawaiians). For example, the risk of total hip replacement for white women 40 years to 84 years of age was 4.4%, compared with 1.1% for Japanese women and 1.7% for Chinese women of the same age group. Compared with published data, the incidence was similar for Chinese in Hawaii and San Francisco; however; whites in Hawaii had a total hip replacement incidence less than half that of whites in San Francisco. Lifestyle differences might account for the lower incidence of total hip replacement for whites in Hawaii, compared with those in San Francisco. The lower incidence among Asians suggests a possible genetic basis for osteoarthritis.