Abstract
Cigarette smoke contains noxious substances associated with alteration in thyroid gland function and bone metabolism in smokers. Serum cotinine, triiodothyronine (T3), thyroxine (T4), thyroid stimulating Hormone (TSH), calcium, phosphate and vitamin D levels were estimated in 100 smokers and 50 non-smokers. The smokers were classified into light and moderate smokers based on smoking pack-years. Serum cotinine, T3, T4 and TSH were determined using ELISA, calcium and phosphate by colorimetric methods and Vitamin D by HPLC. Statistical analysis was done using analysis of variance, Student’s t-test and Pearson’s correlation. The level of significance was set at p< 0.05. The mean diastolic blood pressure (p = 0.002), cotinine (p = 0.0001), T4 (p = 0.014) was significantly higher in smokers compared to non smokers. While vitamin D was significantly lower (p = 0.0001) in smokers compared to non smokers. There was however no significant difference (p<0.05) in the mean values of systolic blood pressure, BMI, T3, calcium, phosphate and TSH between the two groups. There were significant variations in the mean systolic blood pressure (p = 0.040), diastolic blood pressure (p =0.0001), cotinine (p =0.0001), T4 (p = 0.036), vitamin D (p = 0.0001) among non smokers, light and moderate smokers. There was an increasing trend in the systolic and diastolic blood pressures and cotinine with the moderate smokers having the highest values. In contrast, there was a decreasing trend in the vitamin D with the moderate smokers having the lowest values. There were however no variations in the mean values of the other parameters among the three groups. Cigarette smoking may have no effect on serum calcium, phosphate, T3 and thyroid stimulating hormone levels. However it is associated with a decrease in serum vitamin D and an increase in T4 levels and blood pressure.