K. Suganthy
BACKGROUND
Smoking is one of the most common addictions of modern times and needs to be studied in a community as a public health issue. Also, smoking is a modifiable risk factor for type-2 DM. The smoking-related diseases share common pathophysiologies of imbalance of systemic oxidants and antioxidant status, increased inflammatory reactions, insulin resistance and dyslipidaemia. Biochemical assay of serum Gamma-Glutamyl Transferase (GGT) activity is a low cost and highly sensitive laboratory test. Studies have indicated GGT is moderately elevated before the onset of other traditional risk factors for type-2 DM. So, among hepatic markers, the baseline GGT analysis can be an early risk marker of type 2 diabetes in cigarette smokers has to be studied.
MATERIALS AND METHODS
This is a case-control study on male cigarette smokers. 57 smokers were studied clinically and biochemically for plasma insulin, glucose and liver enzymes including GGT using standard biochemical methods and compared with 42 age and sex matched non-smokers as controls.
RESULTS
The mean serum GGT in smokers (25.45 ± 10.8) was increased compared to non-smokers (18.8 ± 5.8). Smokers GGT (r=0.396) and HOMA-IR (r=0.352) showed significant positive association with duration of smoking (p<0.05) than fasting blood glucose. Multiple regression analysis showed only duration of smoking (p=0.001) as a dependable factor on GGT. 24.5% (14/57) smokers showed an increased GGT >24 IU/L. Regression analysis showed none of the diabetic risk factors were observed to be dependent on GGT including other liver enzymes. Regression analysis showed GGT is not an independent risk factor for DM. Although, the mean fasting blood glucose (91.4 ± 21.3), BMI (26.1 ± 9.3) and HOMA-IR (7.3 ± 2.3) was increased among cigarette smokers with GGT >24 IU/L.
CONCLUSION
The baseline GGT assay in cigarette smokers might be associated with the proinflammatory status or be a marker of oxidative stress of smoke toxins. Smokers with baseline GGT >24 IU/L develop insulin resistance should be investigated in future longitudinal studies for prediabetes to consider cigarette smoking as an important modifiable risk factor of type-2 DM.
