Income inequality in obesity among women and men by gender and race/ethnicity, 1988-1994 to 1999-2004

Obesity has reached epidemic proportions among U.S. adults from all racial/ethnic groups. While basic income disparities in obesity are well documented, little is known about recent trends for women and men, overall or within racial/ethnic groups. Data from the third National Health and Nutrition Examination Survey (NHANES 1988-1994) and NHANES 1999-2004 were used to examine income disparities among Black, Mexican-American, and White women and men, 20 years and over. Mexican-Americans were furthered distinguished by primary language spoken at home. Change in weight status distribution (normal weight, overweight, obese, severely obese) for each racial/ethnic/gender group was examined, and the slope and relative index of inequality for each weight status were calculated. Women in each racial/ethnic group had the highest proportions of obese or severely obese individuals compared with their male counterparts. White women had the highest proportion of normal weight individuals (40%) while over half of Black women were obese or severely obese. Obesity, especially severe obesity, increased for each racial/ethnic/gender group over the 10-year period. Income inequality did not change appreciably between surveys but varied according to gender and race/ethnicity. For example, in 1999-2004, an inverse relationship between income and obesity was observed for women (strongest among White women); yet, a positive relationship was observed among men (except White men). The complex relationships between income and obesity by gender and race/ethnicity show that solutions to reducing income disparities in obesity must be responsive to each racial/ethnic/gender group. The large increases in extreme obesity in all groups warrant urgent attention.