Researchers from Weill Cornell Medical College and Cornell University in New York concluded on the basis of a new study that if you want to avoid lungs damage, then you are advised not smoke cigarette at all.

The urine of 121 healthy volunteers was collected for bronchoscopy and then the researchers determined the smoking status based on the levels of nicotine and cotinine present in their urine.

No traces of nicotine and cotinine were detected in the urine of 40 people who were classified as non-smokers; people who had low levels were classified as occasional smokers and those with high levels were categorized as regular smokers.

The lung biopsies of regular smokers and non-smokers were compared, through which 372 genes were identified by the researchers, which get activated by tobacco smoke.

Then they checked the activity of genes in occasional smokers, which showed that out of 372 genes, 128 had been triggered presumably by cigarettes and 41 genes were modified.

Next step of the researchers was to check the levels of nicotine and cotinine had to be in the urine before they detected changes in the lung genes.

Further, the researchers have found that the group of genes that had strong actions in occasional smokers was the same group that is most active in regular smokers.