Introduction

PRESTYLE - Physical Activity and Early life risk factors for obesity in childhood: a Longitudinal Study in Preschool Children.

The prevalence of paediatric obesity has increased dramatically in the last decades, in most countries, as well as in Portugal. This continued broaden is particularly alarming not only for the increasing risk of multiple medical comorbidities, but also due to the tracks into adulthood. The increased obesity prevalence in children has increased awareness of physical inactivity as a public health problem. Indeed, it is commonly assumed that reduced physical activity (PA) and the increase sedentary behaviour (SB) are implicated in the aetiology of childhood obesity.

Early infancy is a period of rapid weight gain and some behaviour such as increased television viewing; increased energy intake and decrease in PA may all contribute to the development of overweight among children. Some studies indicate that levels of total energy expenditure (TEE) in young children are very low and levels of SB exceptionally high. However, few studies of PA in kindergarten children have been undertaken so far. Thus, the aims of this study were, therefore:

(1) to use accelerometer to quantitatively describe levels of habitual PA in a sample of 3- to 5-year-old children;

(2) to describe normal developmental changes in PA longitudinally;

(3) to provide evidence of the role of the early life environment in the later risk of obesity;

(4) to assess tracking of PA and obesity (BMI) over a 3-year period;

(5) to determine the association between body mass index status (BMI), PA patterns in preschool children over a 3 year-period.