Income Differentials on Body Mass Index in the U.S. (1971-2002): A Complex Pattern of Consistency and Change within Race-Sex Groups

Virginia W. Chang, University of Pennsylvania
Diane S. Lauderdale, University of Chicago

In this study, we examine income differentials on BMI using a series of comparable, nationally representative samples of U.S. adults, and we consider whether or not differentials have changed over a three decade period from 1971 to 2002. We also consider the varying nature of this association between race-sex groups, and we employ a more flexible modeling strategy than has been used in past studies to more accurately represent the relationship between BMI and income. We find significant non-linear relationships between BMI and income that have changed for some groups and remained consistent for others despite large increases with time in mean BMI along the entire income continuum. Moreover, these findings suggest that previous generalizations about the association between income and weight status may have been hampered by a mis-specification of the relationship, particularly among men and blacks, where it is often concluded that there is no association.