Abstract

The relationship between smoking and severe health injuries is documented by numerous publications. The negative effects of nicotine absorption also apply to dentistry, A correlation between smoking and oral cavity carcinomas, periodontal diseases and impaired intraoral wound healing following surgical therapy has been shown by different working groups. In this study we tried to make an objective judgment about tobacco consumption by determination of cotinine as the major metabolite of nicotine. It was investigated, whether the test allows a clear discrimination between nonsmokers and smokers, and whether a quantitative relationship between urinary cotinine and the number of daily smoked cigarettes can be estabtished. For this purpose, cotinine was determined in nonsmokers (N=29) and smokers (N=36) with a liquid-phase radioimmunoassay, and creatinine was measured with a mechanized Jaffé reaction. The urinary cotinine values in nonsmokers ranged from 20.5 to 166 µg/L or 23.0 to 322 µg/g urinary creatinine. The corresponding medians of the distributions were 67.8 µg/L urine or 55.5 µg/g urinary creatinine. The urinary cotinine values in smokers were between 486 and 9124 µg/L or 946 and 13,482 µg/g urinary creatinine. The corresponding medians of the distributions were 2816 µg/L urine or 4090 µg/g urinary creatinine. The results show that the test permits a clear distinction between nonsmokers and smokers, because there is no overlap of the two distributions, and because the difference between the highest value in nonsmokers and the lowest value in smokers (320 µg/L urine or 624 µg/g urinary creatinine) represents a sufficient safety interval with regard to misclassifïcation of the smoking status. For the mathematical description of cigarette consumption by the urinary cotinine and urinary creatinine values, four regression models were developed. As regression equations for the linear, logarithmic, exponential and power model y = 0.00136 x + 6.99, y = 7.179 ln x - 45.8, y = 7.28 e^0.0000987x and y = 0.103 x^0.572 were determined, where y denotes the number of cigarettes smoked within 12 hours and x denotes the cotinine/creatinine quotient [µg/g]. The corresponding correlation coefficients are r = 0.559, r = 0.577, r = 0.612 and r = 0.693. With these algorithms it is possible to objectify the smoking behavior of patients by measurement of merely two urinary parameters and thus monitor compliance with respect to reduction or cessation of cigarette smoking by a noninvasive procedure.

DOI: Clin. Lab. 1999;45:141-155