[Utility of Mahalanobis distance in evaluating the results of health examination].
A method using Mahalanobis distance (D2), the general probability distance in multivariate analysis, was studied for evaluating the results of health examination. D2 of each subject was computed by a personal computer with a BASIC program, and those whose D2 values lay out of 95% confidence interval were considered to be abnormal. In the present study, the mean value and standard deviation come from a normal range of Japanese, and the correlation coefficients between two items were obtained from blood donors in the hospital. These three parameters were necessary for calculation of D2. To examine the availability of this method, the data of a health examination on 370 new employees from 18 to 25 yr in age were analyzed with 9 items, including systolic pressure (SBP), diastolic pressure (DBP), serum glutamic oxaloacetic transaminase activity (GOT), serum glutamic pyruvic transaminase activity (GPT), serum gamma glutamyl transpeptidase activity (GGTP), serum total cholesterol (TCHO), serum triglyceride (TG), number of erythrocytes (RBC), and concentration of hemoglobin (Hb). It was shown that the data distributions of GOT, GPT, GGTP, and TG were log normal, and those of the other items were normal. With this method, 39 persons were also judged as abnormal from 46 subjects diagnosed to be abnormal by doctors, and the remaining 7 were missed but could be classed to be normal, as six of them had only slightly high levels of GPT (33-39 IU/l) and/or GGTP (42-57 IU/l), and one had a slightly high SBP (146 mmHg).(ABSTRACT TRUNCATED AT 250 WORDS)
Koyama
Y
Y
Department of Hygiene, Shinshu University School of Medicine.
D000328:Adult; D005069:Evaluation Studies as Topic; D005260:Female; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods* / Q000592:standards; D015999:Multivariate Analysis; D016272:Occupational Health; D012016:Reference Values