Historical approaches to human growth studies limit the present understanding of growth biology

Background/aims: Measurements of children's size have (1) provided a biosensor of health and well-being in their environment; (2) provided references for clinical assessment, and (3) informed public health efforts to ameliorate living conditions. Size-for-age measurements offer no information about the growth trajectories by which children achieve size, and growth trajectories offer no information on proximal mechanisms underlying growth biology. Increasing attention to the biological processes themselves, only estimated by anthropometric parameters and statistically based growth proxies, is needed.

Methods: A literature overview of human growth measurement interpretations.

Results: Aspects of study design, analysis and reliance on common conventions contribute to limitations in growth biology knowledge. Examples include conflating both the concepts of size and growth and incremental gains in either weight or length as manifestations of growth; nonuniformity in the use of growth trajectory-derived clinical categories, and conventional approaches to data collection and analysis.

Conclusions: Intensive studies of individuals hold promise for expanding normal growth biology knowledge. Focusing on growth (not merely size), length (not weight alone) and individual growth patterns (not growth chart phenotypes) are important tactics. Benefits include clarification of mechanisms by which nutrition and metabolism influence growth, new solutions to abnormal growth states and improvements in long-term health consequences.