Effects of cigarette-smoking on bone mass as assessed by dual-energy X-ray absorptiometry and ultrasound

In order to elucidate the influence of nicotine smoking on bone mass in elderly women, bone mass was cross-sectionally assessed by dual energy X-ray absorptiometry (DXA) in total body, hip and lumbar spine, as well as with ultrasound of calcaneus and phalanges of the hand. Subjects were 1,042, 75-year old women, recruited on a population basis (Osteoporosis Prospective Risk Assessment (OPRA) study). We found bone mineral density (BMD) to be lower in hip (0.71 vs. 0.76 g/cm(2), p < 0.0001 for femoral neck) and total body (0.96 vs. 1.02 g/cm(2), p < 0.0001) in current smokers compared to never-smokers. There was no difference in BMD of the lumbar spine between current smokers and never-smokers. Bone mass as assessed by ultrasound of the calcaneus was lower for speed of sound (p < 0.01), broadband ultrasound attenuation (p < 0.0001) and stiffness (p < 0.0001) in current smokers than in never-smokers. No differences were found for ultrasound measurements of the phalanges between smokers and never-smokers. Also, weight and current physical activity as assessed by a questionnaire differed significantly between current smokers and never-smokers. There was no evident difference between former smokers and never-smokers in any of the skeletal regions assessed by DXA or ultrasound. After correcting for differences in weight and physical activity, current smokers had lower BMD in all hip sites (p < 0.05) and total body (p < 0.01) compared to never-smokers. Ultrasound and BMD spine did not differ between these two groups after correction for weight and physical activity. We conclude that nicotine smoking has a negative influence on bone mass independent of differences in weight and physical activity. This difference is detected by DXA but not by ultrasound measurements of the calcaneus or the phalanges. The present data are encouraging since no bone mass differences were found between former and never-smokers.