LAUSR

Purpose This research examined the association of cigarette smoking and altitude with the blood levels of 25-hydroxy vitamin D, testosterone and carotid artery thickness. Patients and methods This comparative cross-sectional study involved 37 non-smokers and 24 smokers from a high-altitude area (≥2245 m above sea level) and 40 smokers and 40 non-smokers from a low-altitude area (39–283 m above sea level). The blood testosterone level was determined spectrophotometrically, and the 25-hydroxy vitamin D concentration was measured by ELISA. The IMT of the right and left carotid arteries was determined using ultrasound imaging. Results Smoking notably elevated the thickness of the intima media of the right and left carotid arteries at both high and low altitudes (p ≤ 0.001). Smoking at high altitude was associated with a significant increase in the concentration of 25-hydroxy vitamin D and testosterone, while at low altitude it was associated with a significant decrease in both parameters (p ≤ 0.046). Conclusion These contrasting results suggest that future studies should focus on finding out if other biochemical parameters show any significant differences in smokers or/and non-smokers when they are tested at elevated height and sea-level. This indicates that dose modifications of medicines (related to alterations in vitamin D and testosterone levels) should be kept in mind while treating smokers and non-smokers at elevated height above sea level.