Test of a new components method for age-at-death estimation from the medial end of the fourth rib using a modern Spanish sample.

Recently, Verzeletti et al. (Am J Forensic Med Pathol 31:27-33, 2010) developed a new components method for the estimation of age-at-death from the sternal end of the fourth rib. This approach consists of the assignment of numerical scores for several age-related morphological characteristics, which are then inserted into a regression equation for predicting chronological age. The present study tested the accuracy of the new components method on a sample from Spain, consisting of 58 males and 36 females. The results demonstrated that the regression equation devised by the aforementioned authors for an Italian male sample was less accurate when applied to the Spanish population sample. This was true for separate male and female samples, as well as a combined-sex sample. A pair of population-specific regression formulae was then generated from the Spanish sample data in an attempt to improve the accuracy of the age estimate. The new equation which incorporated sex as an independent variable did not yield more accurate age estimates than a non-sex-specific equation. Furthermore, both of these formulae provided only marginally more accurate results for the Spanish sample compared to the original Italian equation. Thus, the standard errors of the estimate associated with these population-specific models (8.1-8.9 years) were still noticeably larger than the 5.2 years observed by Verzeletti and colleagues in their Italian study. Given the high standard errors associated with the age estimates for the Spanish population sample, the new rib components method should be used in conjunction with other adult aging techniques.