interpret the“normality” of an individual’s size (Tanner 1981 ). The objective
comparative framework of size among children became an important sociopolitical
tool with the expanding appreciation that infant mortality and poor child growth
reflected deprived living conditions and child labor inequities. Over the last century,
attained height has been used as a primary indicator of the health of nations, with
growth surveillance programs a mainstay of public health operations at national,
local, and individual levels (Tanner 1981 ). The prevalence of stunting —an
age-adjusted measure of low height—is a key component of the United Nations
Children’s Fund (UNICEF) criteria for assessing health and well-being on a global
scale (UNICEF 2014 ), and on an individual basis, plotting size from infancy
onwards is a standard practice in pediatric clinical medicine (Grummer-Strawn et al.
2010 ). Growth charts are a pillar of both public health and clinical medicine,
defining the health of populations and communities through the size of their chil-
dren and offering a handy tool for monitoring individual normality (Cole 2012 ).
Much of this work has roots in the methodological work and descriptive data
collection efforts conducted by anthropologists and human biologists.
Biomarkers of Size
Growth charts provide references by which to understand how big children of
various ages are relative to one another. This provides some perspective on how
“well”they have grown. Size reflects growth to date, and shorter children are either
genetically small or they are poorly growing children, reflecting a less healthy
biological, social, and/or environmental milieu. The charts summarize measures of
individuals’size at a group level, illustrating percentiles of size for age with
smoothed curves (Lampl and Thompson 2007 ) for a handy reference visualization
by which to compare any individual child to others (Fig.4.1). These charts com-
monly represent the 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles of size
for age attained by children in the samples from which they are derived. Relative
size among peers of similar backgrounds is used as a health indicator, and the
biomarker of size presented by a percentile number offers a clinical strategy. A child
in the extremes of the percentile distribution on the growth chart, either very large
or very small, raises concerns and often prompts medical follow-up to rule out
physiological processes that may be inhibiting“normal”growth, and/or to initiate
treatments to get children“back on track.”
The use of growth chart percentiles as diagnostic biomarkers is both potentially
helpful and problematic. An objective criterion for clinical action offers an
evidence-based approach to interventions and assures attention to potential health
risks. For example, by definition, concerns are raised when an individual is“too
small”in size, variously defined as below the 10th, 5th, or 3rd percentiles, with the
call to action dependent on risk profiles associated with age- and sex-specific
conditions. At the earliest ages, fetuses who are below the 10th percentile of
expected weight for gestational age are described as having intrauterine growth
4 The Lived Experience of Growing 51