Prevention of Obesity in Children: An Intervention Based on Child Care Centers Belonging to the Mexican Institute of Social Security

Over the past 20 years, the prevalence of obesity in Mexico has increased dramatically among individuals across the lifespan, including even the youngest populations.National data from the Mexican Institute of Social Security (IMSS) population estimate that nearly 15% of children aged 2 to 5 years are obese as defined by World Health Organization criteria. Obesity among preschool-aged children is of serious public health concern due to its adverse effects on children's physical and psychosocial well-being,and its association with obesity risk in later childhood, adolescence, and young adulthood. Furthermore, because dietary and activity patterns have not been firmly established, early childhood represents a critical window for prevention.

Given the high number of preschool children enrolled in out-of-home child care in Mexico, important opportunities exist for developing child care-based obesity prevention interventions focused on promoting healthy activity and dietary behaviors among children. Child care centers provide an ideal setting for a multi-level, ecologic intervention that includes strategies aimed at environmental level changes within the child care center, as well as individual level behavior change among the children. In addition, child care-based interventions have the potential to reach out to the children's families to improve the child's home food and activity environment.

Setting and study population. There are 142 IMSS child care centers in Mexico City. To allow for adequate attention to details in the development of the intervention and evaluation protocol and to contain costs prior to broad dissemination of the program, the investigators will focus on 16 IMSS child care sites for this proposal, which together provide care for approximately 450 children aged 2 to 5 years. At each IMSS child care center a team consisting of a nutritionist, a nurse, an educator, and child care technicians provides the daily care and education programs for the children. This extensive personnel structure provides the ideal infrastructure for implementing the proposed multifaceted intervention.

Since the intervention is a primary prevention program, the investigators will make the program available to all children, aged 2 to 5 years, at the child care centers, regardless of their current weight status. Children with chronic conditions that limit ability to measure height and weight or substantially interfere with growth, physical activity, or dietary recommendations will be excluded.

Data analysis for outcome measures. Intent-to-treat analyses to compare study outcomes between the intervention and control groups at post-intervention and at 6-months follow-up will be used. To compare the difference the age-associated increase in body mass index (BMI) among intervention and control groups (Aim 1), the mixed effects model with group (child care center) as the clustering factor will be used, as recommended by several authoritative sources. Similar analyses to compare the difference in prevalence of overweight (Aim 2), in the children's weight-related behaviors (Aim 3a), in the children's home environment (Aim 3b), and in the environment of the child care center (Aim 3c) will be performed.