Obesity is one of the most pressing public health challenges worldwide. It is caused by multifactorial causes and could lead to increased risk of cardiometabolic disease. Although obesity is not as common in children as adults currently, the temporal increase in the prevalence of childhood obesity is greater than that of adulthood obesity in multiple countries. However, current public health measures are mostly focused on adult obesity and may not translate to children.

Obesity and overweight were traditionally regarded as the result of an individual’s unhealthy lifestyle (diet and physical activity), but there is increasing recognition that these interact with many other factors; both upstream environmental factors (social, political, and economic) and individual (genetic, psychosocial and biological) factors. These are likely to impact over the life-course. Exposures to environmental obesogens in-utero and/or in early life might also be important. The interactions between these factors are complex. For example, with global economic growth, the reduction in walkability and green spaces are likely to reduce children’s physical activity level which, in turn, result in childhood obesity. These are also compounded with air pollution which might directly and indirectly (also through physical activity) influence obesity. Even though genetic factors account for 40%-70% of obesity risk, the independent effect of individual loci may not completely explain the pathogenesis of obesity because of gene-environment interaction.

Most studies to date focused on individual risk factors for obesity. However, to identify an effective public health strategy to tackle childhood obesity, this study will investigate the interactions between and relative importance of those factors. Additional, since childhood obesity may not necessarily track into adulthood, this study will also look into factors that could predict persistent obesity from childhood to adulthood, which should be clinically most relevant.