The influence of smoking on postmenopausal bone markers

Smoking is an important determinant of osteoporosis. There are a wide variety of mechanisms by which smoking induces bone toxic effects. Such mechanisms include alterations in calciotropic hormone metabolism and intestinal calcium absorbation, dysregulation in sex hormone production and metabolism, alterations in adrenal cortical hormone metabolism and direct cellular effects of cigarette use on bone cells. To assess the effect of smoking on vitamin D, serum parathyroid hormone (PTH) and calcium we studied 86 postmenopausal women (50-70 years), who were smokers previously or who were current smokers. Our results are compare with those of 34 women of the same age who had never smoked. Differences between the three groups were analyzed using one-way analysis of variance and Student’s unpaired t-test. Postmenopausal women who were current smokers had significantly reduced levels of serum 25OHD (P 0.01) and PTH (P 0.001). There was no difference in serum calcium between never smokers, ex-smoker and current smokers (P=0.184). The unchanged plasma calcium among smokers in spite of lower levels of PTH and 25OHD could be a result of a decreased calcium uptake in bone.