Ethnic differences in arthritis : obesity responsible

the researchers found, osteoarthritis risk was slightly increased for Native American and African American women compared to non-Hispanic white women, while Asian women were at lower risk than whites.

Risk factors for osteoarthritis were more common among black, Native American and Hispanic women than whites; 57.9 percent of African Americans were obese, for example, compared to 51 percent of American Indian women, 41.9 percent of Hispanic women, and 32.9 percent of non-Hispanic whites.

Prevalence of physical inactivity followed the same pattern, with 30.1 percent of black women falling into the lowest activity group, compared to 19.5 percent of whites.

Osteoarthritis prevalence among the youngest women participating in the study also varied by ethnicity, with 39.3 percent of Hispanic women in their 50s reporting arthritis, 36.4 percent of Native Americans, 33.8 percent of black women, 25.8 percent of Asians and 22.6 percent of whites.

The researchers hypothesize that excess weight could contribute to arthritis in two ways: by increasing physical stress on joints, and also by increasing bone mineral density, which may increase bone stiffness and thus contribute to the breakdown of cartilage.

The findings, along with other studies showing that black and Hispanic women suffer more pain and disability from osteoarthritis than do whites, offer "strong evidence that body weight and BMI may be large contributing factor to the number and severity of osteoarthritis symptoms, further elaborating the importance of postmenopausal women, especially African-American, Hispanic, and American-Indian women, maintaining a healthy weight,"