Smoking-Induced Bone Defects May Be Due to Oxidative Damage in Postmenopausal Women

Objective: Smoking has been implicated as a risk factor for bone defects in postmenopausal women (PMW). The exact mechanism by which it exerts its negative effects on bone is not yet fully known. The purpose of this study was to investigate the impact of smoking on the oxidative status in PMW) and to assess the relationship between one mineral density (BMD) and these oxidant/antioxidant parameters. Material and Methods: The female subjects were randomly selected with simple sampling method according to smoking habits among those presenting to outpatient menopause clinics for menauposal symptoms [smokers (n= 30), mean age was 49.7 +/- 3.5 and non-snonsmokers (n= 30), mean age 51.2 +/- 3.4]. Antioxidant enzymes including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and paraoxonase (PON), oxidative stress biomarkers such as malondialdehyde (MDA) and nitric oxide (NO) levels, hormonal status, bone turnover markers and BMD were evaluated. Results: Femoral bone and lumbar spine dual-energy X-ray absorptiometry (DEXA) results revealed that the rate of osteopenia and osteporosis in smokers and non-smokers were 75% and 52.5%, respectively. The T-scores were lower in smokers than non-smokers (median -2.7 [percentile, (-3.8%)-(-23%)] and median -1.4 [percentile, (-1.9%)+0.9%)]; p< 0.001). The activities of antioxidant enzymes SOD, GSH-Px and PON were lower and the levels of oxidative stress products MDA and NO were higher in smokers than in non-smokers (p< 0.001). We found a significant correlation between decreased T-score and oxidative stress parameters in the smoking group. A positive correlation was found between the T-score and SOD (r= 0.39, p= 0.035), GSH-Px (r= 0.37, p= 0.046) and PON (r= 0.48, p= 0.008). There was a negative correlation between the T-score and the NO level (r= -0.39, p= 0.032), but no significant correlation was found between MDA levels and the T-score (r= -0.15, p= 0.430). Conclusion: This increased oxidative stress may represent a risk factor for the progress of osteoporosis in smoking PMW. Further studies are needed to clarify the role of smoking on oxidative bone damage and the underlying mechanisms must be addressed.