Childhood overweight and family income.

Objective: To examine the relation of family income, expressed relative to the poverty threshold, to the prevalence of childhood overweight, and to determine whether the association differs by race/ethnicity and time period.

Subjects And Methods: Most analyses were based on 2- to 19-year-old participants (n=10,409) in the US National Health and Nutrition Examination Survey (NHANES) from 1999 to 2004. Additional analyses were performed using NHANES data collected from 1971 to 1994 to determine whether family income showed similar associations with childhood overweight (body mass index [BMI] for age > or = CDC 95th percentile) over this time period.

Results: The relation of family income to childhood overweight differed (P < .001) by race/ethnicity in 1999-2004. As compared with children below the poverty level (annual family income of about $19,200), the odds of overweight among children from families with incomes of 4 or more times the poverty threshold were 0.63 (white children) and 0.51 (Mexican-American children). Among black children, however, overweight was positively associated (odds ratio of 1.12) with family income. Although family income was not associated with childhood overweight in 1971-1974, the observed associations also differed by race/ethnicity in the 1976-1980 and 1988-1994 surveys. Furthermore, the association changed during the past few decades among Mexican-American children (P = .03 for secular trend), but not among white or black children.

Discussion: Although family income is related to childhood overweight, the association varies by race/ethnicity. Additional information on the reasons for these racial/ethnic differences may help in the development of appropriate interventions.