Nguyen T Tuan1, Nancy F Butte, Youfa Wang. 1. Johns Hopkins Global Center on Childhood Obesity and Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
Abstract
BACKGROUND: Associations between demographic-socioeconomic characteristics and childhood obesity are complex in the United States. OBJECTIVE: We examined associations between demographic-socioeconomic characteristics (age, sex, race-ethnicity, family income, household size, and birthplace) and adiposity measured by dual-energy X-ray absorptiometry in US children. DESIGN: Data were from 8-19-y-old US children enrolled in NHANES 2001-2004 (n = 5436). Adiposity was expressed as the fat mass index (FMI = fat mass/height(2); in kg/m(2)), percentage body fat (%BF), and prevalence of normal, overfat, and excess fat corresponding to %BF <25%, 25-29.9%, and ≥30% in boys and <30%, 30-34.9%, and ≥35% in girls, respectively. We used sex-specific linear and multinomial logistic regression models adjusted for demographic-socioeconomic factors. RESULTS: The prevalence of excess fat was higher in Mexican American (36%) than in white (28%; P ≤ 0.10) and black (21%; P < 0.05) boys; higher in Mexican American (44%) than in white (36%; P ≤ 0.10) and black (35%; P < 0.05) girls; and higher in US-born (38%) than in foreign-born (29%; P ≤ 0.10) Mexican American boys. In boys, %BF was higher in Mexican Americans and lower in blacks than in whites (P < 0.05). Adiposity was negatively associated with family income in white boys and girls and in Mexican American girls (P < 0.05). Racial-ethnic disparities in adiposity persisted (P < 0.001) after control for demographic-socioeconomic factors available in NHANES. The R(2) for sex-specific models of %BF or FMI regressed on age, race-ethnicity, family income, household size, and birthplace ranged from 2% to 11%. CONCLUSION: The association between demographic-socioeconomic factors and adiposity among US children varied substantially by age, sex, and race-ethnicity.
BACKGROUND: Associations between demographic-socioeconomic characteristics and childhood obesity are complex in the United States. OBJECTIVE: We examined associations between demographic-socioeconomic characteristics (age, sex, race-ethnicity, family income, household size, and birthplace) and adiposity measured by dual-energy X-ray absorptiometry in US children. DESIGN: Data were from 8-19-y-old US children enrolled in NHANES 2001-2004 (n = 5436). Adiposity was expressed as the fat mass index (FMI = fat mass/height(2); in kg/m(2)), percentage body fat (%BF), and prevalence of normal, overfat, and excess fat corresponding to %BF <25%, 25-29.9%, and ≥30% in boys and <30%, 30-34.9%, and ≥35% in girls, respectively. We used sex-specific linear and multinomial logistic regression models adjusted for demographic-socioeconomic factors. RESULTS: The prevalence of excess fat was higher in Mexican American (36%) than in white (28%; P ≤ 0.10) and black (21%; P < 0.05) boys; higher in Mexican American (44%) than in white (36%; P ≤ 0.10) and black (35%; P < 0.05) girls; and higher in US-born (38%) than in foreign-born (29%; P ≤ 0.10) Mexican American boys. In boys, %BF was higher in Mexican Americans and lower in blacks than in whites (P < 0.05). Adiposity was negatively associated with family income in white boys and girls and in Mexican American girls (P < 0.05). Racial-ethnic disparities in adiposity persisted (P < 0.001) after control for demographic-socioeconomic factors available in NHANES. The R(2) for sex-specific models of %BF or FMI regressed on age, race-ethnicity, family income, household size, and birthplace ranged from 2% to 11%. CONCLUSION: The association between demographic-socioeconomic factors and adiposity among US children varied substantially by age, sex, and race-ethnicity.