Improving precision in age estimation from the female pubic symphysis: a novel technique for CT

Due to the skeletal emphasis of both physical and forensic anthropology, biological profiling has traditionally been advanced through the study of archaeological, historical, donated, and autopsied remains. In recent years, this has grown to include samples obtained through medical imaging, specifically that of computed tomography (CT), though these investigations have remained largely retrospective. While these types of studies are in keeping with past precedent, this preference for anonymous skeletal material under- utilizes the other half of the human equation – the living owners of those skeletons and the ways in which they live their lives.
Through the development of a new technique – the Truesdell Composite Method, or "TCM," this study sought to explore the feasibility of incorporating direct public engagement into the process of biological profiling research. Over the course of six months, 1,238 volunteers (653 male, 585 female – ages 18 to 101) were interviewed, face-to-face, before being CT scanned at Oxford University's Churchill Hospital. These interviews were facilitated by a six-page questionnaire detailing demographic (biological affinity, age, height, weight, etc.), lifestyle (diet, activity level, inflammation, infection, osteoporosis, arthritis, smoking by ounces or cigarettes per day, alcohol consumption by unit per week, etc.), and pregnancy history (age at first birth, epidural, SPD, caesarean, birth weight, length of labour, etc.). The answers to these questions, along with the results of additional Suchey-Brooks (1990) and Hartnett (2010) symphyseal analyses, were then compared to the actual age of each individual. Sex (p=0.008, effect size=1.86), smoking (p=0.010, effect size=1.85), activity (p=0.033, effect size=0.69), and menopause (p=&LT;0.0001, effect size=7.69) all returned significant results while, surprisingly, parity did not (number of pregnancies, p=0.846; number of births, p=0.895), nor did any pregnancy related factors.
Subjects were placed into appropriate Suchey-Brooks ranges an average of 89.4% of the time, but only 49.4% of the time was the mean within a decade of the actual age and, within that, only 27% of the time was it within 5 years of the actual age. This is likely a reflection of the sample’s propensity towards older individuals (&Tilde; 50% over 65 years). The Hartnett Method fared less well overall, with subjects being placed into appropriate ranges 75.5% of the time but, then, within the ranges themselves, fared slightly better than Suchey-Brooks with means within 10 years of actual age 65.4% of the time and 39.1% within 5 years. When using the TCM, estimations to within 10 years of actual age increased to 83.9% and to 67.7% within 5 years. For Suchey-Brooks, this constitutes a 34.5% increase in precision to within 10 years of the actual age and a 40.7% increase in precision to within 5 years. For the Hartnett Method, precision to within 10 years was increased by 18.5% and to 28.6% within 5 years. It is hoped that the TCM, and with it these increases in precision, will be particularly relevant to females and to individuals over the age of 60 years.

Advisor: Marquez-Grant, N
Banks, M