observational data, collected through careful and frequent longitudinally collected
measurements and narratives of growing children, provide a viewpoint on how
growth is“seen”in real time. Investigative biomarkers illuminate a very different
perspective of growth due to the specificity of their reference points, resulting in a
fundamentally different construct of growth itself.
Defining Healthy Growth
With the recognition of the profound role played by environmental factors on
children’s health as manifest in their size, graphical depictions of infant and
childhood growth began appearing in medical journals and textbooks at the turn of
the nineteenth century, followed closely by increasing public health concern over
defining both appropriate feeding methods and developmental milestones (Weaver
2011 ). A fundamental scientific leap for the establishment of more formal clinical
references and standards was Galton’s 1875 progress in statistics that permitted the
development of percentiles and, thereby, a quantitative approach by which to
Fig. 4.2 Individuals do not grow continuously, little by little each day, as the graphical growth
chart curve implies. Instead, they grow by episodic, aperiodic saltations of 0.2 to more than 1.0 cm
in length/height within 24 h, separated by intervals varying from days to weeks, when no growth is
accrued. This results in a step-wise pattern of actual change through time, shown here for an infant
to illustrate the details missed by the growth curve summary
50 M. Lampl et al.