New York, May 22 (IANS): If you are a smoker using the so-called "light" cigarettes, for their lower levels of tar or nicotine, think twice. According to a study, you may be at an increased risk of developing a certain form of lung cancer that occurs deep in the lungs.

Cigarettes labelled as lights, milds, or low-tar -- also known as high-ventilation (light) cigarettes -- are generally considered to have a lighter, less pronounced flavour, lower levels of tar, nicotine, or other chemicals than regular cigarettes. They are thus marketed by the tobacco industry as a "healthier" option.

On the contrary, these cigarettes may have actually contributed to the rise of lung adenocarcinoma -- the most common type of lung cancer, the researchers said.

The findings, appearing in the Journal of the National Cancer Institute, showed that the higher incidence rates of lung adenocarcinoma were attributable to the filter ventilation holes, which allow smokers to inhale more smoke that also has higher levels of carcinogens, mutagens and other toxins.

"The filter ventilation holes change how the tobacco is burned, producing more carcinogens, which then also allow the smoke to reach the deeper parts of the lung where adenocarcinomas more frequently occur," said Peter Shields from Ohio State University.

Holes in cigarette filters were introduced 50 years ago and were claimed to be safer.

"This was done to fool smokers and the public health community into thinking that they actually were safer," Shields said.

"Our study suggests a clear relationship between the addition of ventilation holes to cigarettes and increasing rates of lung adenocarcinoma seen over the past 20 years. What is especially concerning is that these holes are still added to virtually all cigarettes that are smoked today," he added.

The US Food and Drug Administration (FDA) should take immediate action, possibly banning use of ventilation holes on cigarettes, the researchers urged.