Associations between household income, height and BMI in contemporary US children: infancy through early childhood

Abstract

Background: Previous studies report positive associations between household income and height in childhood and negative associations between income and body mass index (BMI). No study has evaluated concurrent associations in early-life.

Aim: To evaluate the association between household income and anthropometric development in early-life.

Subjects and methods: The Early Childhood Longitudinal Study–Birth Cohort (ECLS-B) is a representative sample of US children born in 2001 and followed from ∼9 months through 5 years. A generalized linear mixed modelling framework estimates income associations to the levels and velocities of height and BMI.

Results: A doubling of permanent income is associated with an ∼0.26 cm height advantage over the ages of the sample and an approximate 0.11 cm/year faster velocity at 9 months. All race–sex sub-groups show some positive association between income and height. Income shows little association to BMI at 9 months but by 5 years a doubling of income is associated with a 0.25 kg/m² lower BMI. This is suggested to derive from a lower BMI velocity associated with higher income. The BMI relationships are generally reflective of white and Hispanic children.

Conclusion: The findings suggest that associations between income and anthropometric development in US children have origins in early-life.

• Early-life
• growth
• socioeconomic