Changes in body mass index z score over the course of the academic year among children attending Head Start

Acad Pediatr. May-Jun 2010;10(3):179-86. doi: 10.1016/j.acap.2010.01.008. Epub 2010 Apr 15.


Objective: We tested the hypothesis that among 3- to 5-year-old children attending Head Start, body mass index z score will decline during the academic year and increase during the summer.

Methods: We used retrospective longitudinal growth data collected over 5 academic years from 1914 children (51% boys, 62% white) enrolled in a Michigan Head Start program. Changes in body mass index (BMI) z score, calculated as annual rate of change, during 2 academic years and the intervening summer were assessed by piecewise linear regression analysis. Potential covariates were gender, single-parent status, program year, race/ethnicity, age at initial enrollment, and family income (divided by household size).

Results: Mean BMI z score at the start of Head Start enrollment was 0.52 (95% confidence interval [95% CI] 0.39 to 0.65). Mean annual rates of BMI z score change were: -0.07 (95% CI -0.28 to 0.14) during the first year of enrollment, 0.62 (95% CI -0.0005 to 1.23) over the summer, and -0.82 (95% CI -1.50 to -0.13) during the second year of enrollment. The effect was most robust among girls of minority race/ethnicity.

Conclusions: Head Start is associated with a shifting of BMI z scores toward the norm among low-income preschool-aged children, particularly among girls of minority race/ethnicity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Body Mass Index*
  • Child, Preschool
  • Early Intervention, Educational*
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Retrospective Studies
  • Socioeconomic Factors
  • Time Factors