Salivary thiocyanate: a biochemical indicator of cigarette smoking in adolescents

Saliva is considered to be critical for the maintenance of healthy oral mucosa, and oral fluids provide an easily available, non-invasive medium for the diagnosis of a wide range of diseases and clinical situations. The purpose of this study was to estimate the thiocyanate (SCN) level in saliva of cigarette smokers and compare it with that of nonsmokers.

The present study comprised 100 subjects, of which 50 had a habit of tobacco smoking. The other 50 neither smoked nor chewed tobacco and comprised the healthy control group. The age and sex (all males) of both groups of subjects were matched. All the patients were in the age group of 25 to 40 years. The group of smokers was divided into subgroups according to duration and frequency of smoking. Duration group 1: smoking for a period of 4-7 years; duration group 2: smoking for a period of 8-15 years; duration group 3: chronic smokers, smoking for a period of more than 15 years. Frequency group 1: patients smoked half pack of cigarettes, i.e. 4-6 per day; frequency group 2: patients smoked one pack of cigarettes, i.e. 7-11 per day; frequency group 3: patients smoked more than one pack, i.e. >11, per day. Saliva was collected by the spitting method. Unstimulated whole saliva was refrigerated at 4°C and processed within 24 h. The estimation of thiocyanate in saliva was done according to Densen et al (1967).

The present study clearly indicates a significant increase in salivary thiocyanate level in tobacco smokers as compared to nonsmokers (P < 0.0001). Comparing salivary SCN in different duration groups, the salivary SCN level was significantly lower in group 1 vs groups 2 and 3, with P < 0.0001. In terms of smoking frequency, the salivary SCN level was significantly lower in group 1 vs group 3, P < 0.0001. It is also evident that there was an increase in salivary thiocyanate levels with increased duration and frequency, thus showing a positive correlation between them.

The findings of this study suggest that salivary thiocyanate can be used as a safe and acceptable prevalence measurement for cigarette smoking behaviour.