Interpolation of the Maresh diaphyseal length data for use in quantitative analyses of growth

• Published in: International journal of osteoarchaeology 2021-03, Vol.31 (2), p.232-242
• Main Authors: Spake, Laure, Cardoso, Hugo F. V.
• Format: Article
• Language: English
• Subjects: Age; Archaeology; bioarcheology; Forensic osteology; growth and development; interpopulation comparison; long bone; nonspecific stress indicator; osteological stress marker; Quantitative analysis; Standard deviation
• ISSN: 1047-482X; 1099-1212
• DOI: 10.1002/oa.2942

The Maresh data are commonly used in bioarcheological growth studies as a representation of diaphyseal growth in a modern and healthy group of children. However, several problems with the way the data were reported have limited its use in quantitative analyses of growth. In this paper, we present updated and interpolated values for long bone length for age for use in calculating z‐scores, percentages of expected length, and other quantitative measures of growth. The Maresh mean and mean + 1 standard deviation values for the sexes separately and combined were first corrected for radiographic magnification. Several modeling approaches were then evaluated. This testing suggested that the best fit was provided by two third‐order polynomials fit to data ≤24 and ≥24 months, respectively. The resulting regressions were used to calculate age‐specific mean and standard deviation values in 1‐month intervals from birth until 12 years (0–144 months). Differences between the original and new values are minimal and do not exceed 1 mm. However, as the old Maresh values required rounding age down to the last attained threshold by as much as 5 months, there are differences between z‐scores calculated with original versus new values of up to 2 z‐score units, especially in children under 3 years of age where growth velocity is highest. Although these updated values do not solve the problems that made age estimation from the Maresh data unadvisable, they will be of use to researchers in conducting more precise growth studies in bioarcheological contexts.