Prevalence of Osteoporosis Using DXA Bone Mineral Density Measurements at the Calcaneus

A total of 1455 people (727 women and 728 men) from the Hortega cohort were studied. The densitometric studies were carried out in the calcaneal region using a Peripheral Instantaneous X-ray Imaging (PIXI) Lunar bone densitometer. We established three cut-off points (−1.6, −2.0, −2.5). One-hundred twenty-five patients (67 men with a mean age of 47 ±13 yr and 58 women with a mean age of 66 ±8 yr) from internal medicine outpatient clinics who were undergoing densitometry of the calcaneus, spine, and hip were subsequently studied. The prevalence of osteoporosis in women with a calcaneus T-score −1.6 was 12.4%, which is comparable to the 12.7% obtained with an axial densitometer in a Spanish population. The prevalence in men was 7.8%, with a calcaneus T-score of <−2.0. In women, the highest sensitivity (85%) was obtained with a calcaneus T-score of <−1.0 and the highest specificity with a calcaneus T-score of <−2.5. In men, the best sensitivity (61%) was obtained with a calcaneus T-score of <−1.0 and the best specificity (98%) with a calcaneus T-score of <−2.5. A calcaneus T-score <−1.6 is an adequate cut-off to establish the prevalence of osteoporosis in population studies. In women, a calcaneus T-score of >−1.0 enables the diagnosis of the disease to be excluded, whereas a calcaneus T-score of <−2.5 enables the diagnosis to be confirmed and treatment to be initiated in both men and women.