Chronic smokeless tobacco consumption contributes to the development of renal diseases in the human male volunteers

Tobacco is consumed mainly in two forms named as smoking tobacco and smokeless tobacco.1 The smokeless tobacco (SLT) consumption is greatly prevalent in at least 70 low, middle and high income countries, consumed by more than 300 million people.2 Smokeless tobacco is ingested as chewing, sucking and through the nasal mucosa, but not smoked. Smoking bans in public places has increased, the consumption of smokeless tobacco has risen as an alternative source of cigarettes.3 Smokeless tobacco products are available in Indian market in multiple forms like khaini, gutkha, mawa, panmasala with tobacco, betel containing lime, catechu, zarda, and dry leaves of tobacco.4 Nicotine is major alkaloid and acts as drug specific present in the leaves of Nicotiana tubacum tertiary amine consists of pyridine and a pyrrolidine rings.5 The major portion of metabolism in nicotine is convert the cotinine and 3-hydroxycotinine in smoker users.6,7 Different people convert different percentage of nicotine to cotinine and metabolize cotinine differently at different rates.8 Cotinine acts as a marker of nicotine exposure and a major metabolite and its detection is performed in blood, saliva and urine samples. Smokeless tobacco products could promote the production of oxygen derived free radicals that enhance the higher rates of lipid peroxidation. Urinary malondialdehyde is one of the products of lipid peroxidation process and used as a marker of oxidative stress. The reactive nitrogen species include nitric oxide and peroxynitrites with active groups disrupts and damage the DNA and proteins in the cells.9 The adverse effects of smokeless tobacco on renal function have gained more attention. Uric acid is the end product of purine metabolism in blood and marked it acts as an early sign of kidney injuries.10 Oral intake of tobacco by chewing also increased the excretion as nicotine which can be absorbed from oral mucosa.11 Urinary excretion of nicotine and cotinine can be used as an index of smokeless tobacco consumption and prevalence. Urinary albumin is a sensitive marker of glomerular injury and microalbuminuria indicates renal damage induced by smokeless tobacco. The aim of the present study was to determine the excretion of nicotine and cotinine in the urine of gutkha and khaini users and their relationship with renal complications.