The burden of overweight and obesity has reached epidemic levels globally. According to the World Health Organization in 2013, 42 million children under the age of 5 years were overweight or obese. Overweight and obesity are major risk factors for non-communicable diseases such as cardiovascular diseases or diabetes. These factors have also been linked with respiratory illness like asthma or sleep apnea in children. In addition, more recently, overweight and obesity have been longitudinally associated with decreased pulmonary function parameters during childhood and adolescence. However, previous studies are limited by a lack of repeated measures on lung function and by a lack of control for potential confounders, such as physical activity and diet. Also, to date, studies have used body mass index (BMI) as the main measure of overweight and obesity, although it has been recently suggested that body composition would be a better marker because of the potential different effects of fat mass and lean body mass on lung function. Fat mass has been shown to have a negative effect on lung function whereas lean mass positively influences respiratory function.

This project thus aims to longitudinally assess the association between body composition and lung function development up to 16 years of age.