To probe into the application value of the height shortening value as the self-examination index of the middle-aged and aged group's osteoporosis or reduced bone mineral density in communities.Four communities were selected by cluster sampling at random in Changsha city to be the objects of study, among which women were 45 years old or older and men were 60 years old. Difference and the percentage proportion of the height shortening between the height of the research objects which was measured at their youth and the height measured at this study, were calculated. Mineral density of the anteroposterior lumber spine L2-L4, the left femur neck of each object of study with the DPX-IQ dual energy X-ray (DEXA) were both examined. Results examined by DEXA were recognized as "Golden Standards" and different absolute and relative height shortening values were taken as positive cutoff points. Sensitivity, specificity and Youden's index were calculated to draw the receiver operator characteristic curve in order to get the positive cutoff which was most suitable to both sensitivity and specificity, and to calculate the predicative values of that self-examination method among different groups.3 cm of height shortened seemed to be the positive cutoff of the self-examination of osteoporosis, and its sensitivity, specificity and Youden's index were 75.4%, 76.7% and 0.521 respectively. 2 cm of height shortened was suggested as the positive cutoff of the self-examination method of reduced bone mineral density, while its sensitivity, specificity and Youden's index were 81.7%, 75.6% and 0.573 respectively. In this self-examination method, positive predicative value was the highest (76.4%; 88.7%) among the women group aged over 65.Certain height-shortening value could be used as the rough index of screening osteoporosis of reduced bone mineral density, which set a simple and easy way of self-examination for the middle-aged and elderly population.
