Background

The goal of this systematic review was to determine the impact of obesity prevention approaches in early care and education programs on the weight status of children aged two years to five years. A variety of intervention strategies targeting behaviors that impact body weight were utilized across the body of evidence. Most approaches were multicomponent, with a combination of interventions targeting children, their parents and staff of early care and education programs.

Conclusion Statement

Moderate evidence suggests that multicomponent obesity prevention approaches implemented in child care settings improve weight-related outcomes in preschoolers. A combination of dietary and physical activity interventions is effective for preventing or slowing excess weight gain and reducing the proportion of young children aged two years to five years who are overweight or obese.

2015 DGAC Grade: Moderate

Methods

Literature searches were conducted using PubMed, EMBASE and Cochrane databases to identify studies that evaluated the obesity prevention approaches in early care and education settings. Studies that met the following criteria were included in an original Nutrition Evidence Library (NEL) systematic review used to update the evidence base included in a systematic review conducted by Zhou, 2014: Randomized controlled trials (RCTs), non-randomized controlled trials and before-and-after studies; humans between the ages of two years and five years who were healthy or at elevated chronic disease risk; subjects from the United States; and published in English in peer-reviewed journals. The date range used to identify existing systematic reviews was January 2009 to February 2014. The date range used to update the evidence base with primary articles was January 2012 to March 2014. The intervention or exposure was an obesity prevention approach conducted in an early care and education setting. The outcomes were weight-related measures.

Data from each included article were extracted and risk of bias was assessed. The evidence was qualitatively synthesized, a conclusion statement was developed and the strength of the evidence (grade) was assessed using pre-established criteria including evaluation of the quality and risk of bias, quantity, consistency, magnitude of effect and generalizability of available evidence.

Findings

• This evidence portfolio included one existing systematic review (Zhou, 2014) and a de novo NEL systematic review to update the evidence base. The Zhou, 2014 review included 15 controlled trials published between 2000 and 2012; the NEL review included seven studies (eight publications) published between 2012 and 2014.
• • The studies used a variety of intervention strategies targeting behaviors which impact body weight. Most approaches were multicomponent, with a combination of interventions targeting children, their parents and staff of early care and education programs. The primary weight status outcomes of interest were body mass index (BMI) and BMI Z-score.
• In the body of evidence available, there is a large diversity in obesity prevention approaches, making comparison across studies challenging. Despite this variability, multicomponent interventions were effective in reducing BMI and preventing excess weight gain.
  • Seven of 10 multicomponent studies included in the Zhou, 2014 review demonstrated improvements in weight-related outcomes. Six of the seven interventions included in the NEL review demonstrated that multicomponent interventions effectively reduce BMI or prevent excess weight gain in children aged two to five years.

Limitations

The ability to draw strong conclusions was limited by the following issues:

• Differences in the populations sampled, outcome measures, duration or exposure of interventions
• Interventions of short duration and with a short follow-up period.