Background Bone mineral density is a variable dependent on age, sex and race, comparing this measurement with a reference population determines the risk of osteoporotic fractures. These values are provided in the software of the equipment used in BMD measurement; they are usually subtracted from a Caucasian population, when compared with a Hispanic population, it can alter the estimation of the mean deviation
Objectives To establish BDM at the lumbar spine and femoral neck in a healthy adult population aged between 20 and 39, stratified by age and sex groups using dual Xray absorptiometry, and to determine whether their behavior is different from the estimates currently used
Methods Cross-sectional study. In a focus group, a questionnaire was designed to detect healthy individuals according to their bone metabolism, subsequently it was applied to the study population to identify eligible individuals according to the inclusion criteria: Colombian adults from both sexes, aged between 20 and 39 years who had signed an informed consent. We devised the questionnaire to identify healthy individuals according to bone metabolism, standardized of staff that applied the questionnaire to individuals, technical and medical staff who analyzed the tests, daily calibration of equipment, use of the latest technology equipment iDEXA, General Electric. Sample size was performed with average and standard deviation of BMD of the reference population equipment manufacturer with a power of 80% and 0.05 type I error. Nonprobability sampling. To assess the prevalence of diagnostic classification according to WHO criteria, a population of patients over 50 years was chosen to compare the TScore obtained with the reference values of the equipment manufacturer and the new TScore calculated with reference values of the study population. The concordance of diagnostic classification was evaluated by a weighted kappa.
Results 805 individuals were assessed with the questionnaire densitometry was not performed in 97 individuals who were eligible, 276 were ruled out by the questionnaire and 432 were eligible. The values found at the lumbar spine for each group were: 1.150 gr/cm2 (SD:0.11) and 1.180 gr/cm2 (SD:0.10) for women and men between 20 to 29 years old, and 1.169 gr/cm2 (SD:0.10), 1.209 gr/cm2 (SD:0.10) for women and men between 30 to 39 years old, respectively. At the femoral neck, 0.991 gr/cm2 (SD:0.10), 1.119 gr/cm2 (SD:0.13), for women and men between 20 to 29 years old, and 0.970 gr/cm2 (SD:0.11), 1.079 gr/cm2 (SD:0.13) for women and men between 30 to 39 years old, respectively. With the manufacturer reference value, osteopenia and osteoporosis was overestimated at the lumbar spine in 3% of women and 9% of men; and was underestimated in 7% of women in the femoral neck. Kappa weighted test to evaluate concordance was significative in both sexes, in femoral neck (FN) and lumbar spine (LS) (women LS 0.8972, FN 0.8914; Men LS 0.7879, FN 0.9711).
Conclusions We demonstrated that the behavior of BDM is lower than the one found in other latitudes and that are used as reference values in the equipment employed in this country. The diagnosis of osteoporosis in women is underestimated at the femoral neck (7%) and is overestimated level of the lumbar spine in women (3%) and men (9%).
Disclosure of Interest E. Jáuregui Consultant for: Pfizer, Speakers bureau: Pfizer, Roche, BIOPAS, Abbvie, M. Galvis: None declared, V. Moncaleano: None declared, C. Aldana: None declared, Y. Muñoz: None declared