Effect of Aging on Cardiothoracic Ratio in Women: A Longitudinal Study

Abstract

Background: The effect of aging on the components of the cardiothoracic ratio (CTR) in the chest roentgenogram in women remains obscure. There have been only a few reported studies that have investigated longitudinal changes of the CTR in women. Objective: To determine whether there is an effect of aging on the CTR in women. Methods: The study population consisted of 110 women who attended an annual health screening and underwent chest roentgenography both in 1981 and 1990 in a mountain village in Japan. We used the data obtained from an annual health screening in order to determine thoracic diameter (TD), cardiac diameter (CD), and lung height (LH) and then calculated the CTR. We analyzed CTR, TD, CD, and LH on the basis of the age of the participants. Results: In the cross-sectional analysis of the groups stratified by age in 1981, mean CD and CTR increased, and TD decreased in the advanced-age group. The percentage of radiographic cardiomegaly (CTR >50%) strikingly increased in the advanced-age group. In the longitudinal analysis between 1981 and 1990, the mean CD increased, and the mean TD decreased significantly. The mean CTR increased by 2.0% (95% CI 1.2–2.8%). The changes of the CTR in 9 years were positively correlated with those of CD and negatively correlated with those of TD and LH. The longitudinal data generally accorded with the cross-sectional data, except LH. Conclusions: The CTR in women increases with aging as a result of the increase in CD, except in the case of advanced old age, and the decrease in TD. LH could be another major factor that has an influence on CTR. Caution should be exercised to avoid overestimating CTR when LH changes. The classical upper limit of 50% for CTR in our adopted method should not be applied to elderly women because of the possibility that changes with normal aging are misclassified as abnormal findings.