Age estimation based on a combined arteriosclerotic index.

This study introduces a new quantity, the combined arteriosclerotic index (CAI), which is defined as the ratio between the diameter and the longitudinal prestrain of an artery. The longitudinal prestrain has been adopted as the ratio between the in situ length and the excised length of the abdominal aorta, and is a measure of arterial elasticity. During ageing, arteriosclerosis is manifested by the loss of pretension and by enlargement of the diameter of the artery. CAI combines these two effects. A sample of 61 female and 194 male autopsy measurements of human abdominal aortas shows that CAI correlates significantly with chronological age (R = 0.916/0.921; female/male). The sample had the following parameters: age 53 ± 19/48 ± 16 years; diameter of the abdominal aorta 12.4 ± 2.2/13.4 ± 2.1 mm; and longitudinal prestrain 1.13 ± 0.10/1.15 ± 0.10 (mean ± sample standard deviation; female/male). The resulting CAI was 11.2 ± 2.7/11.9 ± 2.6 mm. The classical linear regression model was employed for age estimation by CAI. The model gave a residual standard deviation of 7.6/6.3 years and a 95% prediction interval range of  ± 15.4/12.5 years (female/male). A two-sample t-test confirmed that there are significant differences between the female and male population during ageing, reflected by CAI, unlike longitudinal prestrain. It was concluded that CAI is a suitable predictor of age at time of death and is easily obtainable in the autopsy room.