Data for: A modified Michaelis-Menten equation estimates growth from birth to 3 years in healthy babies in the US

Background: Standard pediatric growth curves cannot be used to impute
missing height or weight measurements in individual children. The
Michaelis-Menten equation, used for characterizing substrate-enzyme
saturation curves, has been shown to model growth in many organisms
including nonhuman vertebrates. We investigated whether this equation
could be used to interpolate missing growth data in children in the first
three years of life and compared this interpolation to several common
interpolation methods and pediatric growth models. Methods: We developed a
modified Michaelis-Menten equation and compared expected to actual growth,
first in a local birth cohort (N=97) and then in a large, outpatient,
pediatric sample (N=14,695). Results: The modified Michaelis-Menten
equation showed excellent fit for both infant weight (median RMSE: boys:
0.22kg [IQR:0.19; 90%<0.43]; girls: 0.20kg [IQR:0.17;
90%<0.39]) and height (median RMSE: boys: 0.93cm [IQR:0.53;
90%<1.0]; girls: 0.91cm [IQR:0.50;90%<1.0]). Growth data
were modeled accurately with as few as four values from routine well-baby
visits in year 1 and seven values in years 1-3; birth weight or length was
essential for best fit. Interpolation with this equation had comparable
(for weight) or lower (for height) mean RMSE compared to the
best-performing alternative models. Conclusions: A modified
Michaelis-Menten equation accurately describes growth in healthy babies
aged 0–36 months, allowing interpolation of missing weight and height
values in individual longitudinal measurement series. The growth pattern
in healthy babies in resource-rich environments mirrors an enzymatic
saturation curve.