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.

**研究目的：** 本研究旨在探究吸烟与海拔高度对血清25-羟维生素D（25 hydroxyvitamin-D）、睾酮水平以及颈动脉内膜中层厚度的影响。

**研究方法：** 本观察性病例对照研究共纳入141名受试者：其中高海拔地区（海拔≥2245米）队列包含37名非吸烟者与24名吸烟者，低海拔地区（海拔39~283米）队列包含40名吸烟者与40名非吸烟者。血清睾酮水平采用HUMAN diagnostics公司的试剂盒通过分光光度法检测；血清25-羟维生素D浓度则采用CTK Bioteck公司的ELISA试剂盒进行测定。采用超声成像技术检测双侧颈动脉的内膜中层厚度（IMT）。

**研究结果：** 无论高海拔还是低海拔地区，吸烟均能显著增加双侧颈动脉的内膜中层厚度（P值≤0.001）。在高海拔地区吸烟可显著升高血清25-羟维生素D与睾酮浓度，而在低海拔地区吸烟则会显著降低二者的血清浓度（P值≤0.046）。

**研究结论：** 高海拔地区吸烟对血清25-羟维生素D与睾酮浓度具有正向影响，而低海拔地区吸烟则会显著降低二者的血清浓度。