Estimation of the Prevalence of Latent Abnormalities in the Lung and the Accuracy of Indirect Chest X-ray Examination among Japanese Workers of Different Age Groups

Abstract

It is considered that annual chest x-ray (CXR) examination can be restricted to workers by age; however, adequate epidemiological evidence is needed regarding the difference in the effectiveness of CXR examination between younger and older age groups. This study attempted to estimate the prevalence of latent abnormalities (P) in the lung and the false negative rate (F) and false positive rate (G) of examinations among workers of different age groups. 112,482 subjects who were screened for three consecutive years with no findings at the first screening, were selected. The proportion of positive findings at the second screening and the proportion of negative findings at the third screening were incorporated into a stochastic model, and 5-yr-age-specific P, F, and G were estimated. P tended to increase with increasing age. F was 40-45% in <45-yr-old subjects and was only 10% in the older age groups. G showed a steady increase with increasing age. This study indicates that the nature of findings differs between younger and older age groups, and this difference affects the accuracy of examination. In Japan, the age of workers should be considered when a CXR examination is performed.