Forensic age estimation from aspartic acid racemization (AAR): Scrutiny of multiple source samples

Accurate age estimations have significant medico-legal repercussions and is crucially needed for identification strategies of unidentified bodies or living individuals in forensic anthropology. Aspartic acid racemization (AAR) provides the most accurate and highly reliable age estimates for the adults from different source samples like teeth, bones, cartilage, sclera, and blood etc., though with varied accuracy and reliability levels. Present article aims to summarize the comparative accuracy and reliability of forensic age estimates from multiple bodily source tissues/samples based on their aspartic acid racemization. A total of 173 articles were retrieved by searching different scientific database and other literary data sources which used AAR for forensic proteomics purposes. 49 articles satisfied the step-wise exclusion-inclusion criteria and were selected for the theoretical review; and only 16 studies were meta-analysed following a systematic analysis approach. The reviews revealed that tooth samples, specifically dentine, provide the most accurate and precise age estimates from aspartic acid racemization. The meta-data analysis revealed that aspartic acid racemization can be adopted as an advanced method of age estimation and the sample/tissue selection is the most crucial factor for such estimates using AAR. Majority of the age estimation methods have been reported for ageing the younger individuals or pediatric remains; AAR is one of the novel ageing methods that provides most precise and reliable age estimates for the adults.