Obesogenic environment and childhood obesity.

The increasing prevalence of obesity in youth has contributed to the growing global burden of chronic diseases (e.g. diabetes, cardiovascular diseases and cancers), which has been largely accounted for by obesogenic behaviours and environments. Previous studies have focused on the influences on obesity of multidimensional environmental indicators, which have mixed effects, for example, built environmental factors, food environmental factors and neighbourhood safety. After a thorough search of all databases, I found a limited body of reviews on the associations of basic environmental factors. A basic environmental factor, from a perspective of geographic information systems, is an indicator constructed by only one-step spatial function, without ambiguous effects on obesity. In contrast to basic obesogenic environmental factors, an example of mixed environmental factor is neighbourhood safety, which is a complex measure of night light, crime rate, traffic volume, speed limit, smoothness of roads and many other factors of injury. Without a sufficient, up-to-date understanding of the roles of basic obesogenic environmental factors in obesity, the uncertainties will propagate and lead to more uncertainties in the association between indicators and obesity.