A Multilevel Intervention to Increase Physical Activity and Improve Healthy Eating Among Young Children (Ages 3-5) Attending Early Childcare Centres: the Healthy Start Study

Childhood obesity is one of the greatest challenges facing public health in the 21st century. In 2010, an estimated 43 million preschool aged children suffered from overweight or obesity and another 92 million were at risk of being overweight. From 1990 to 2010, the prevalence of overweight and obesity in children under the age of 5 increased from 4.2% to 6.7%, and it is estimated that 60 million children will suffer from being overweight by 2020. In Canada, the prevalence of obesity in preschool aged children is three times higher than the global average. Being overweight in childhood has been associated with compromised emotional health and social wellbeing. Much of the excess weight in obese children is gained before the age of 5 years and many studies indicate that adiposity tracks into childhood. Further, children who become obese before the age of 6 are at least four times more at risk of obesity in adulthood.

The problem of obesity is multifactorial, but is primarily influenced by energy intake and energy expenditure. Eating habits are established early in childhood and can be sustained for many years. Data show that only 29% of Canadian preschool aged children meet recommendations for fruit and vegetable intake and 23% for grain products. Further, 79% of 4-5 year olds consume food of little nutritional value (ex: chips, french fries, candy, chocolate, soft drinks, cake and cookies) at least once a week and other studies have demonstrated that empty calories are making up as much as 40% of their total caloric intake. Similarly, a recent review demonstrated that physical activity (PA) levels in early childcare centers (ECC) are generally low, and that time spent in sedentary state is elevated. It was estimated that children in ECC accumulate an average of 7 to 13 minutes of moderate-to-vigorous PA (MVPA) during the course of a 7 hour day. Correspondingly, recent data suggest that the prevalence of children with poor physical literacy is high and that low physical literacy competence is negatively associated with PA, cardiorespiratory fitness and weight status. These data are troubling given that sedentary and physical activity levels track over time.

Several organizations have recognized the need to counter pediatric obesity and to develop physical activity and nutrition-based interventions for pre-school populations. More than half of young Canadians between the ages of 6 months and 5 years spend around 29 hours a week in ECC, making them rich environments for implementing strategies to help children adopt healthy lifestyles. For example, one pilot study demonstrated an increase in fruit and vegetable intake following nutrition education and increased availability of healthy foods in ECC. Another intervention study integrating physical activity in all aspects of the preschool curriculum reported a 2 minute increase in classroom MVPA as assessed by accelerometer. However, both a systematic review on obesity prevention interventions in children under 5 years and another on obesity prevention policies, practice and interventions in ECC reported limited success of current interventions in positively influencing physical activity levels, dietary behaviour, or body composition. The authors suggest that the least successful interventions were unidimensional, while the most successful interventions were those with a positive impact on knowledge, abilities and competence, suggesting that interventions should be conceived based on comprehensive behaviour change models. It was also found that few interventions focused on physical activity and eating behaviour in combination, and that future interventions should target both behaviours simultaneously.

Interventions promoting healthy weight in children should encompass a broad spectrum of concerted actions and be based on best available knowledge from research and practice. Healthy Start, an intersectional multilevel physical activity and healthy eating promotion in preschool aged children, was developed on these bases. The aim of the current study is to lead a comprehensive evaluation of the Healthy Start intervention using an experimental research design.

The Intervention The population health approach is based on the concept that in order to positively influence population-level health outcomes, one needs to account for the wide range of health determinants [39], recognise the importance and complexity of potential interplay among these determinants, and reduce social and material inequities. Further, interventions adhering to principles of the population health approach rely on best evidence available, stimulate intersectoral collaborations, and provide opportunities for all potential stakeholders to be meaningfully engaged in its development. Several models based on the population health approach have been developed to help guide interventions. These models provide holistic conceptual frameworks which, similar to ecological models, suggest that interventions include a series of concerted actions capable of targeting all levels of influence, including the intrapersonal (biological and psychological), interpersonal (social and cultural), organizational, community, physical environment and political levels.