Bone mineral densitometry in a 55-year-old Indian female

Abstract

Osteoporosis is a condition of the bone, which is diagnosed by performing bone mineral density (BMD) investigation. To diagnose osteoporosis on BMD, we have to focus on T-score and Z-score values on the report. T-score is the standard deviation (SD) of the BMD value of the subject from peak bone mass that is BMD of young age individual. A value T-score less than or equal to −2.5 is considered to be suggestive of osteoporosis. Z-score is the SD of the BMD value from the subject same age group. A value Z-score ≤2.0 is considered to be suggestive of low BMD. As BMD value the mass of mineral per volume of bone, those individual who are shorter their BMD varies as compared to those who are taller. Average Indians are shorter in height as compared to Caucasians. To mitigate this issue, BMD reference data were collected; the Indian Council of Medical Research conducted a community-based multicenter study to derive Indian references for peak bone mass.[1] As T-score is the SD of BMD from peak bone mass and Z-score is the SD BMD from individuals of the same age. It is impossible to have a T-score of −1.7 and Z-score of −3.3 in a particular patient. We want to highlight a BMD report of 55-year-old female whose BMD was performed by GE Lunar DPX DEXA machine for spine BMD, which came out to be 0.903 g/cm2 with T-score of −1.7 also the result shows 81% of BMD of young age. If we back calculate the mean of BMD of peak bone mass or of a young age person, it comes out to 1.115 g/cm2. The Z-score of the same patient comes out to be −3.3 and the result also shows 69% of mean or peak age-matched BMD. If we back calculate the mean of BMD of age matched, it comes to 1.309 g/cm2. BMD of age matched cannot be greater than that of peak bone of young age. Either there is a flaw in the data or the reference data are not representative. However, we still see such reports in our practice, especially in females of age 55 years and around. As the Z-score is ≤2.0, we have to check for secondary causes of osteoporosis. All investigation comes out negative. This wastes the time of treating physicians and adds to the stress and financial burden to the patient, during the time, they are undergoing such investigations. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship None. Conflicts of interest There are no conflicts of interest.