Race/Ethnicity differences in the relationship between obesity and gait speed among older Americans.

Projections indicate that the older American population will become more racially diverse in the future. Therefore, eliminating health disparities among older adults should be a public health priority. Using data from the 1999-2002 National Health and Nutrition Examination Survey, we examined the relationship between obesity, measured by BMI and waist circumference, and gait speed, a performance-based measure of physical function, in 2,285 older adults (≥60 y) in order to determine whether this relationship varies by race/ethnicity. Overweight and obesity, indicated by a BMI ≥ 25 kg/m(2) and a waist circumference in quartiles 3 (male: 102.4-109.9 cm; female: 97.3-106.3 cm) and 4 (male: 110.2-156.6 cm; female: 106.4-147.5 cm), were associated with slower gait speed in non-Hispanic Whites. Among non-Hispanic Blacks, only extreme obesity, indicated by a BMI ≥ 35 kg/m(2) and a waist circumference in quartile 4 (male: 110.2-149.6 cm; female: 106.4-137.7 cm), was associated with a slower gait speed. Among Mexican Americans, only extreme obesity, indicated by a BMI ≥ 35 kg/m(2), was associated with a slower gait speed. Thus we found the relationship between obesity and gait speed differed by race/ethnicity. The goal of eliminating health disparities in access to and quality of health care is only possible when differences in the associations between possible risk factors and physical function are identified.