Smoking and quantitative ultrasound parameters in the calcaneus in 36-year-old men and women

Little is known regarding the association between smoking and quantitative ultrasound (QUS) parameters. Broadband ultrasound attenuation (BUA) and speed of sound (SOS) are believed to provide information on bone quality besides information on bone mineral density (BMD). The aim of this study was to investigate (1) current tobacco smoking; (2) lifetime tobacco smoking; and (3) years since smoking cessation, in relation to QUS and BMD parameters in 36-year-old men and women. Data came from the ninth measurement of the Amsterdam Growth and Health Longitudinal Study (AGAHLS), in which 165 men (36 smokers and 129 nonsmokers) and 178 women (33 smokers and 145 nonsmokers) participated, with an average age of 36 years (SD=0.7). BUA (dB/MHz) and SOS (m/s) of the calcaneus were assessed by using the CUBA Clinical instrument. BMD of the lumbar spine (L1-L4), total hip, and total body were measured with dual-energy X-ray absorptiometry (DXA). We used multiple linear regression analyses with correction for body weight, physical activity, calcium intake, and alcohol consumption. We found no significant associations between smoking and any of the BMD parameters in 36-year-old men and women. However, both current and lifetime tobacco smoking were significantly and negatively associated with BUA in women but not in men. Lifetime tobacco smoking was significantly and negatively associated with SOS in both sexes. The latter association was independent of body weight, calcium intake, physical activity, and alcohol consumption in women, but not in men. Our results suggest that both current and lifetime tobacco smoking are associated with a deterioration in bone quality but not with a reduction in BMD. However, since BMD parameters and QUS parameters were not measured at the same sites, our results may also simply suggest that the calcaneus is affected by smoking at an earlier stage than the lumbar spine, hip, and total body.