• Epidemiology of chronic non communicable diseases
• ENVIRONMENTAL HEALTH
• SPATIAL ANALYSIS
• SOCIAL EPIDEMIOLOGY
• OBESITY

Chaparro et al's study of the relationship between early childhood adiposity and nearby food environment represented an important examination of an understudied population. Although their conclusions are certainly thought-provoking, the methods by which they arrived at these conclusions, though common, left me with questions.

First, the authors characterise the advantages of weight-for-height z-score (WHZ) as ‘more appropriate’ than body mass index (BMI) for studying longitudinal adiposity. Although they are right to point out that WHZ has the advantage of being “independent of height at all ages,” they overlook the fact that over-time variability in WHZ is not independent of level of adiposity1 (figure 1). …