Mandibular bone mineral density measured using dual-energy X-ray absorptiometry: relationship to hip bone mineral density and quantitative ultrasound at calcaneus and hand phalanges

The main aim of this cross-sectional study was the estimation of relationships between mandibular bone mineral density (m-BMD), hip bone mineral densities (BMDs) and quantitative ultrasound at calcaneus and hand phalanges. Correlations between m-BMD and age, years since menopause (YSM) and body size were also evaluated. 42 edentulous persons (36 females and 6 males aged 60.5 +/- 6.9 years) were evaluated. In the group studied no factors affecting bone metabolism (either medical conditions or medications) were noted. Bone status was assessed by dual-energy X-ray absorptiometry (mandible, hip--Lunar DPX-L), and quantitative ultrasound (calcaneus--Lunar Achilles which measures speed of sound (SOS, m s-1) and broadband ultrasound attenuation (BUA, dB MHz-1); and phalanges of the hand--DBM Sonic 1200 which measures amplitude-dependent speed of sound (AD-SOS, m s-1)). CV% for mandibular measurements was 2.06%. m-BMD correlated significantly with the following measurements: femoral neck r = 0.39, p < 0.01; Ward's r = 0.39, p < 0.01; calcaneal BUA r = 0.39, p < 0.01; and phalangeal AD-SOS r = 0.4, p < 0.01. Negative correlation consistent with a significant decrease with age was observed in m-BMD (r = -0.36, p < 0.05) and AD-SOS (r = -0.4, p < 0.01). BMD in the mandible also decreased with YSM (r = -0.47, p < 0.01). m-BMD was correlated with age, YSM, height and weight in stepwise, multiple, linear regression analysis. The following equation was obtained: m-BMD = -2.21 + 0.018 x height (cm) -0.02 x YSM (years) + 0.13 x age (years). It may be concluded that mandibular BMD may be an appropriate measurement site for the evaluation of skeletal status in osteoporosis.