Effect of Smoking on the blood concentration of 25-hydroxyvitamin-D and Testosterone at High and Low Altitude

<b>Objective:</b> This study investigated the effect of cigarette smoking and altitude on the blood level of 25 hydroxyvitamin-D and testosterone and the carotid arteries thickness. <b>Methods:</b><b> </b>This observational case- control study involved 37 non-smokers and 24 smokers from high altitude (≥2245 meters above sea level), and 40 smokers and 40 nonsmokers from low altitude area (39-283 meters above sea level). The blood testosterone level was determined spectrophotmetrically using a kit from HUMAN diagnostics while the 25-hyroxyvitamin concentration was measured by the use of the ELISA kit form CTK Bioteck. The IMT of the left and right carotid arteries was determined using the ultrasound imaging technique. <b>Results:</b> The smoking significantly increased the intima media thickness of the right and left carotid arteries at high and low altitudes (p- value ≤ 0.001). Smoking at high altitude significantly increased the concentration of 25- hydroxyvitamin D and testosterone while at low altitude it significantly decreased both of them (p- value≤ 0.046). <b>Conclusion: </b>At high altitude, smoking had positive effect on the blood concentration of 25- hydroxyvitamin D and testosterone whereas smoking at low altitude significantly decreased the blood concentration of both of 25- hydroxyvitamin D and testosterone.