Cigarette filters, according to researchers, introduced many years ago, which was first introduced to lessen the amount of tar being inhaled by smokers, also increases the risk of lung cancer by altering the properties of smoke and smoking.
In a review of recent research done on changes in rates of lung cancer and changes in the most common type of lung cancer prevalent today, the authors have concluded that the tiny holes for ventilation found in all types of cigarettes are posing a new health hazard.
"The design of cigarette filters that have ventilation can make the cigarettes even more dangerous, because those holes can change how the tobacco burns, allow smokers to inhale more smoke and to think that the smoke is safer because it is smoother,” senior author Dr. Peter D. Shields from The Ohio State University’s Wexner Medical Centre in Columbus told Reuters Health by email.
“This applies to all cigarettes, because almost all the cigarettes on the market have the holes, not just the ones that used to be called lights and ultra-lights,” he noted.
Although the overall rates of lung cancer have declined with reduction of smoking habits in the general population, the rates of lung cancer among smokers have risen considerably say the researchers. Also, they type of lung cancer linked to smoking has also changed since the 1950s.
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According to the researchers, the rates of adenocarcinoma of the lung, the most common type of lung cancer related to smoking, has increased four times in men and eight times in women, with changes in composition and design of cigarettes occurring since the 1950s at the same time. Shields and his team have studied the evidence associating cigarette filter ventilation to the substantial increase in rates of lung cancer. The report was published online on may 22nd in the Journal of the National Cancer Institute.
The ventilation filters did reduce the amount of tar being inhaled when they were tested on smoking machines. However, increase in ventilation which caused the tobacco to burn more slowly, caused the smoker to inhale more puffs per cigarette, resulting in increased inhalation of cancer-causing and toxic chemicals by smokers.
“The use of the ventilation holes yields lower tar only on a machine,” Shields said. “Machines have nothing to do with actual exposures in humans. The holes let them inhale more smoke with more cancer-causing agents. “Because of the claims of lower tar content, though, smokers develop the false belief that a lower tar cigarette is a healthier cigarette, Shields' team writes.
The increase in ventilation also causes particles to be smaller, hence allowing more smoke to reach parts of the lung which were more susceptible. Also, though there has been a decrease in the levels of tar and nicotine with time, when tested on machine, there was been no significant change in the daily intake levels of nicotine among smokers in the last 25 years, the researchers write.
“The evidence shows that more modern cigarettes are riskier for lung cancer,” Shields said. “There are reasons in addition to the holes that also can contribute to the increasing risk, but one does not preclude the other. “Cigarette designs could and should be regulated to address all the possible reasons, Shields said.
“The holes have no health benefits; they serve no health purpose,” he explained. “They do not lower tar delivery to people. So, if they have the potential harm, the FDA can act, even if the science is not perfect. The FDA can require cigarette manufacturers to make filters without the holes. This is easy and they are doing it for some brands already.”
Having filters may indeed be safer, Shields clarified. “This study is about the holes on the filters. We are not saying to remove filters, only to change their designs by removing the holes on the filters.”
“The FDA now has the authority to require the elimination of filter ventilation, as ventilation does not serve any public health purpose and instead provides a false promise of reduced risk,” the study team concludes. “This single action for banning filter ventilation by the FDA is scientifically justified, and within its mandate to improve the public health,” they write.
Previous studies have also given evidence for the ban Shields and colleagues propose, Jonathan M. Samet and Lilit Aladadyan, both from the Tobacco Centre of Regulatory Science at the Keck School of Medicine of USC and the USC Institute for Global Health in Los Angeles, write in an editorial published along the review.
The evidence collected by Shields’ team seems convincing enough to support FDA action, and “given a lack of evidence for countervailing harms, ending filter ventilation could be a ‘no regrets’ action that would benefit public health,” they write.