Biomonitoring of tobacco smoke exposure and self-reported smoking status among general population of Tehran, Iran.

The present study aimed to find a correlation between the self-reported smoking status of the residents of Tehran, Iran, and the urine cotinine as a biomarker of exposure to tobacco smoke. The self-reported data was collected from 222 participants who were living in the urban area of Tehran. The urine samples of participants were collected for cotinine analysis. Urine cotinine was measured by an enzymatic immunoassay technique. Tobacco smoking was reported by 76 (34.23 %) participants as the self-reported data, and the number of males in this report was higher than of females (p < 0.001). By adding the number of the self-reported non-smokers with cotinine levels above the cutoff value of >100 ng/ml to self-reported smokers, the smoking prevalence increased from 34.23 % (95 % CI 28.01-40.88 %) to 36.48 % (95 % CI 30.14-43.19 %). Using the cutoff value, sensitivity and specificity of the self-reported smoking status were respectively 90.12 % (95 % CI 81.46-95.64 %) and 98 % (95 % CI 93.91-99.55 %). The levels of agreement between self-reported tobacco smoking and urinary cotinine concentrations was 95.1 % (k = 0.89, p < 0.001, 95 % CI = 0.81-0.95). Based on the results, self-reported smoking can be a valid marker for assessing the tobacco exposure, and it can be of use in large epidemiological studies.