Quantitative ultrasound and bone mineral density are equally strongly associated with risk factors for osteoporosis

Because resources do not allow all women to be screened for osteoporosis, c linical risk factors are often used to identify those individuals at increa sed risk of fracture who are then assessed by bone densitometry. The aim of this study was to compare calcaneal quantitative ultrasound (QUS) and axia l bone mineral density (BMD) T and Z scores in a large group of women, some with no clinical risk factors and others with one or more risk factors for osteoporosis. The study population consisted of 1115 pre- and postmenopaus al women. A subgroup of 530 women was used to construct reference data for calculating T and Z scores. A total of 786 women was found to have one or m ore of the following risk factors: (i) atraumatic fracture since the age of 25 years, (ii) report of X-ray osteopenia, (iii) predisposing medical cond ition or use of therapy known to affect bone metabolism, (iv) premature men opause before the age of 25 years or a history of amenorrhea of longer than 6 months duration, (v) family history of osteoporosis, (vi) body. mass ind ex CBR (BMI) <20 kg/m(2), and (vii) current smoking habit. Calcaneal broadb and ultrasound attenuation (BUA) and speed of sound (SOS) measurements were performed on a Hologic Sahara and a DTUone and BMD was measured at the spi ne and hip using dual-energy X-ray absorptiometry (DXA). The Z score decrem ents associated with the seven risk factors calculated using multivariate r egression analysis were similar for QUS and BMD measurements. Z score decre ments (mean of BMD and QUS measurements combined) associated with a history of atraumatic fracture (-0.67), X-ray osteopenia (-036), a family history of osteoporosis (-0.23), and a low BMI (-0.53) were all statistically signi ficant compared with women with no risk factors. Z score decrements associa ted with a medical condition or use of therapy known to affect bone metabol ism, a premature menopause or prolonged amenorrhea, or those who were curre nt smokers were not significantly different from zero. As the number of ris k factors present in each individual increased, the mean Z score decrements became more negative, increasing from -0.28 for women with one risk factor to -1.19 for those with four or more risk factors. QUS and BMD measurement s yielded similar mean Z scores for women with one, two, three, or more tha n four risk factors. Using the World Health Organization (WHO) criteria to diagnose osteoporosis for BRID measurements and revised diagnostic criteria for QUS, approximately one-third of postmenopausal women aged 50+ years wi th clinical risk factors were classified as osteoporotic compared with only 12% of women without clinical risk factors. Over two-thirds of postmenopau sal women with risk factors were classified as osteopenic or osteoporotic a nd approximately 28% were classified as normal. The proportion of women cla ssified into each diagnostic category was similar for BMD and QUS. In concl usion, clinical risk factors for osteoporosis affected calcaneal BUA and SO S Z score measurements to tbe same extent as axial BMD Z score measurements . Provided revised diagnostic criteria are adopted for QUS, similar proport ions of postmenopausal women are identified as osteopenic or osteoporotic a s with BMD.