Smoking as a risk factor for bone mineral density in the heel of Japanese men

Bone mineral density (BMD) of the calcaneus was measured in 1736 male Japan ese office workers (age 20-64 yr) using a DX-2000 (Matsushita Industrial Eq uipment, Toyonaka, Japan). The scanning time was 10 s, with an in vitro pre cision error of 0.85% and an in vivo precision error of 1.54%. A significan t gradual loss of BMD was detected between 20 and 60 yr of age, with an age difference of 0.27% per year. Significant determinants for heel BMD were b ody mass index, age, and smoking. A nonsignificant factor was alcohol consu mption. The coefficient of determination was 30.7%. These results suggest t hat smoking is a risk factor for osteoporosis in middle-aged Japanese men.