Urinary levels of nicotine & cotinine in tobacco users

Of the various biochemical markers used to validate the smoking status of a person, nicotine and continine are considered as good markers for both active and passive smoking. In the present study an attempt was made to estimate urinary levels of nicotine and cotinine in healthy individuals from north India using different types of tobacco to identify and validate the smoking status.

Twenty four hour urine sample of 130 healthy volunteers (smokers=70, passive smokers=20, tobacco chewers=20, non smokers=20) were analyzed by high-pressure liquid chromatography (HPLC) assay. Smokers were divided into different groups, viz., cigarette, bidi and hooka smokers.

The mean values of nicotine (ng/ml) and cotinine (ng/ml) in urine were highest in cigarette smokers (nicotine=703.50+/-304.34; cotinine=2736.20+/-983.29), followed by hooka smokers (nicotine 548.0+/-103.47 and cotinine 2379.0+/-424.25), and bidi smokers (nicotine=268.53+/-97.62, cotinine=562.60+/-249.38). There was no correlation of nicotine or cotinine values with smoking index. In passive smokers (nicotine=109.75+/-22.33, cotinine=280.75+/-86.30) and in nonsmokers, the values were much lower (nicotine=55.00+/-13.71, cotinine=7.30+/-2.47) compared to smokers. In tobacco chewers, the values for nicotine and cotinine were 447.75+/-145.09 and 2178.30+/-334.29 respectively.

All forms of tobacco users had significantly higher values compared to passive smokers and nonusers. Thus, cotinine and nicotine levels in urine may be considered as good indicators to assess the exposure to tobacco in our population.