Updated 26 August 2013

Third-hand smoke can be a killer

For the first time a major study has proven that third-hand smoke causes significant damage to our DNA, and becomes even more harmful over time.

For the first time a major study has proven that third-hand smoke causes significant damage to our DNA, and becomes even more harmful over time.

What is third-hand smoke?

  • It is created by tobacco smoke that lingers after a cigarette has been smoked.
  • It’s called third-hand because it is created after second-hand smoke has disappeared.
  • Third-hand smoke is absorbed especially well by fabrics, but will stick to almost all surfaces.
  • Humans are vulnerable to its compounds through skin contact, inhalation and ingestion.
  • It’s especially harmful to crawling children, because it also settles on carpets.

When earlier research pointed to the dangers of second-hand smoke, many smokers saw it as a ploy by anti-tobacco lobbyists to further marginalise them. Many smokers are considerate towards non-smokers, but because of the ones who couldn’t care less, stricter smoking laws were put in place to keep smokers in their place.

And you’d think that with these laws we finally managed to address the dangers of smoking, right? Wrong!

New research proves that the smelly residue (third-hand smoke) which sticks to almost all surfaces long after the second-hand smoke has cleared out can actually cause significant long-term genetic damage to human cells.

"Ours is the very first study to confirm that third-hand smoke is mutagenic," said Lara Gundel, who is part of the team of researchers from the Lawrence Berkeley National Laboratory, in the USA.

Chemical compounds found in third-hand smoke are among the most potent carcinogens around, and are capable of causing most cancers in humans, according to the findings, which were published in the journal Mutagenesis.

“This research supports what many of us have only suspected about the dangers of smoking, not just for the smoker, but also for the non-smoker,” Mercia Axon, the owner of Smokenders South Africa, told Health24.

And Axon is not alone in her sentiment.

“There is no question that government now has to take an even firmer stand than ever before. It’s not enough to confine smokers to smoking rooms or outside areas as the damage done by the smokers and their smoke lingers long after the smoker has departed,” Cape Town-based General Medical Practitioner, Dr. Ryan Jankelowitz, told us.

Jankelowitz is certain that in litigious countries, such as the USA, it will not be long until a non-smoking janitor who develops lung cancer sues his employer for having had him clean the smokers’ room.

“This study will back up his [the janitor’s] claims. It is not a stretch to imagine a scenario where a smoker is soon charged with culpable homicide,” said Jankelowitz.

Everyone’s at risk

And to make matters worse, everyone can be exposed to the lingering toxic particles through skin contact, inhalation, or ingestion. “They [third-hand smoke compounds] cling to surfaces, and when those surfaces are clothing or carpets, the danger to children is especially high,” stressed Gundel.

Furthermore, the researchers found that third-hand smoke is particularly insidious because it’s extremely difficult to eradicate, and is often detected in dust and surfaces more than two months after someone has smoked in an area. Everyday cleaning methods that include wiping, vacuuming and ventilation are not effective in lowering nicotine contamination.

“You can do some things to reduce the odours, but it’s very difficult to get rid of completely. The best solution is to substitute materials, such as change the carpets or repaint,” said co-author Hugo Destaillats.

By using two common in vitro tests, the Berkley team found that third-hand smoke can cause both DNA strand breaks and oxidative DNA damage, which can lead to gene mutation.

They were able to prove that third-hand smoke also becomes more harmful over time.

To do this, they put down paper strips in two smoking chambers. The acute samples were then exposed to five lit cigarettes over 20 minutes, while the chronic samples were exposed to cigarette smoke for 258 hours over 196 days. During that time, the ‘chronic’ chamber was intermittently ventilated for at least 35 hours.

The compounds were extracted from the paper with a culture medium, which was used to make a culture with human cells. The concentrations of the compounds were then measured.

The researchers found that the concentrations of more than half of the compounds studied were higher in the chronic samples than in the acute samples. More DNA damage was also caused by the chronic samples.

"This proves that the cumulative effects of third-hand smoke are quite significant. Our findings suggest the materials could be getting more toxic with time," co-author Lara Gundel added.

However, many people were still not willing to accept how life-threatening cigarettes are, said Smokenders’ Mercia Axon, who hailed the Berkley study as important.

“Perhaps it’s because they are so easily accessible, even by under-aged kids, that they are not considered dangerous. The fact is that cigarettes contain some 4700 chemicals, of which 600 are deadly and 63 are cancer-causing carcinogens,” said Axon.

Death by numbers

In a survey titled The Great South African Smoking Survey 2012, Health24 questioned 8 262 smokers and ex-smokers, and managed to reveal these alarming figures:
  • An estimated 30% of South Africans are smokers.
  • At least 50% of smokers puff between 11 and 30 cigarettes a day.
  • People spend around R200 to R1620 per month on cigarettes.
  • 79% of those surveyed had their first puff before 20.
  • 44% found smoking a cigarette most satisfying after meals, a drink or sex
  • 27% found their first cigarette of the day was the most pleasing.
  • 53% tried quitting more than once.
  • 19% percent have tried quitting up to six times.

About 60% of all South African lung cancer deaths are due to tobacco smoking, and over 8% of all deaths are due to smoking, according to the national Lung Cancer Association. The association also stressed that over 42 000 South Africans die every year of tobacco-related diseases, which includes lung cancer.

Doctor Jankelowitz advises those people wishing to stop smoking, to explore the option of medication such as bupropion and varenicline, or substitute forms of nicotine and even hypnotherapy. He says the common element to any successful attempt at quitting, is the desire to stop smoking.

“And now smokers need to remember that it’s not just for their health, or for the health of those around them, it’s for the health of people who, weeks later, will pass through the places where they’ve been smoking,” concluded Jankelowitz.


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