THE INFRARENAL AORTIC DIAMETER IN RELATION TO AGE - ONLY PART OF THE POPULATION IN OLDER AGE-GROUPS SHOWS AN INCREASE

Objectives: to resolve whether the infrarenal aortic diameter (IAD) co ntinues to increase throughout life; to ascertain the relationship bet ween IAD and age, sex, body size, and smoking status, and to determine whether these factors influence the IAD over the entire range of aort ic diameters ol only in a proportion. Setting: combined cross-sectiona l data fr om two population-based screening programmes for abdominal a ortic aneurysms (AAA) in Huntingdon (U.K.) and Rotterdam (The Netherla nds). Methods: the antero-posterior diameter of the infrarenal aorta s uns measured. The influences of age, gender, body size and smoking sta tus were examined. Results: data were analysed from 3066 women and 827 0 men. In men, mean IAD rose from 20.7mm to 23.5 mm in the older age g roups. However, IADs remained constant below the 75th perentile in men and the 85th percentile in women. Similarly only the top 15-25% of th e aortic diameters were larger in smokers compared with non-smokers. C onclusions: the aortic diameter increased with age in only a minority of the population. Furthermore, known risk factors for ARA contributed to aortic dilatation in only the tipper tail of the frequency distrib ution. Thus only 25% of men and 25% of women may be prone to aortic di latation.