Comparison of Salivary Continine in Smokers and Nonsmokers Health Assessments

Objective: The aim of this study was to validate smoking status by measuring continine levels of saliva samples. We also assayed saliva for p53, a transcription factor, as the dependent variable in order to determine the impact of error on the statistical analysis when using data from medical history questionnaires.

Methods: From a random selection of saliva samples 16 smoker and 16 nonsmoker saliva samples were chosen. Using ELISA, specimens were assayed for continine and p53. Data was tabulated and statistical analyzed using SPSS.

Results: Mean and median continine levels for smokers were 171 ng/ml and 166 ng/ml respectively, with the standard deviation within the group of 36ng. For nonsmokers the means and median were 7.0 ng/ml and 6.2 ng/ml. All these levels correspond to appropriate continine levels for smokers and nonsmokers in a literature review. For the same saliva samples, smokers and nonsmokers have P53 concentration mean and median values 137 ng/ml and 137 ng/ml, similar to normative values per literature review. Low levels of continine, 4 ng/ml and 26 ng/ml, from smoker's saliva samples indicate the absence or sporadic smoking, and invalidate the health history questionnaire. Continine levels in nonsmoking saliva samples, namely, 31 ng/ml, 36ng/ml, and 116 ng/ml, suggest nicotine intake either by smoking, secondhand smoke, infrequent smoking or nicotine replacement. A continine saliva level of 10 ng/ml is commonly used as the cutoff for nonsmoker status. Receiver Operating Curve using questionnaire and continine levels as standard were constructed. The questionnaire data revealed 88% sensitivity and 75% specificity for identifying tobacco users. There is error when comparing group means.

Conclusions: The validity of the health history questionnaire for this nonsmoking population is challenged. This study provides evidence of the lack of construct validity of health history questionnaires to verify smoking and nonsmoking status.