Secular trend in forensic antrhopology

Linda L. Klepinger,1 Ph.D.

Stature, Maturation Variation and Secular Trends in Forensic Anthropology*

REFERENCE: Klepinger LL. Stature, maturation variation and secular trends in forensic anthropology. J Forensic Sci 2001;46(4):788–790. ABSTRACT: A twentieth-century trend for increased stature has received considerable attention in the forensic literature with regard to its effects onstature estimation, but a secular trend for earlier maturation has received little attention. Current evidence indicates that within populations with similar climatic adaptation, truncation or extension of the same trajectory of ontogenetic allometry accounts for the secular trend and the within-cohort stature variation, as well as the scaling of limb proportion to stature and intralimb proportions.Since secular increase is small compared to interindividual variation, the Trotter and Gleser formulae are still appropriate as long as the 95% confidence intervals are applied. A secular trend for increasing childhood and adolescent obesity is associated with a trend for accelerated skeletal maturation, but does not predict a consistent direction or a quantitative correction for traditionalstandards. Secular trends for increased stature and earlier maturation are overshadowed by increasing nonsecular intrapopulational variation. KEYWORDS: forensic science, forensic anthropology, secular trend, stature, maturation, ontogenetic allometry, Ellis R. Kerley

In contrast to the more usual operations of science, i.e., using collections of individual cases to build generalizations, forensicanthropology practice uses generalized observations to arrive at characterizations of individuals. The pitfall in this approach lies in the retained tendency to emphasize the importance of the mean and one standard deviation and to disregard the more extreme values. There is a danger that the central tendencies will acquire a status that distorts natural variation. This variation can be conceptualizedas either synchronic (or populational) or diachronic (or secular). While this conceptual dichotomy is often analytically useful, it may obscure an underlying similarity. In casework it may overemphasize concerns, such as secular trends, that in practice need not be treated differently from populational variation. One source of variation that has received attention from forensic anthropologists isthe well-recognized secular increase in the stature of North Americans over the last century or so. This secular trend may involve change in body proportions, most frequently a relative increase in leg length, although patterns may differ between sexes and among different populations and subpopulations (1). Based on their studies of males from Trotter’s data from the Terry Collection and WorldWar II casualties and more recent data from the Foren1 Department of Anthropology, University of Illinois, Urbana, IL. * Presented at the 52nd Annual Meeting of the American Academy of Forensic Sciences, February 2000, Reno, NV. Received 20 March 2000; and in revised form 16 June 2000; accepted 16 June 2000.

sic Data Bank, Meadows and Jantz (2) and Ousley and Jantz (3) concluded that because thelower limb bones were positively allometric with stature and because of secular changes in lower limb segment proportions, it is generally inappropriate to use regression formulae based on earlier samples, such as the Terry Collection, to estimate stature in the recently deceased. But is this secular trend in positive allometry for American white and black males fundamentally any different fromthe case encountered when dealing with the taller and shorter people that comprise a significant portion of any population cohort? Recent evidence suggests that it is not. Along with their very short stature, the notable body proportions of the African pygmies, with relatively long arms and short legs, had been previously hypothesized to be either a retention of a primitive ape-like trait or the...