Research has shown that smoking cigarettes is responsible for roughly half of all deaths from 12 different cancers in the US.
The study was carried out by the American Cancer Society in Atlanta. It revealed that at least 167,805 cancer deaths every year could be attributed to smoking.
Which cancers are attributed to smoking?
Around 45 per cent of these deaths were due to cancers of the lung, bronchus and trachea. These amounted to the largest proportion of cancers, but the study revealed that about half of the deaths were caused by cancers of the oral cavity, oesophagus and bladder. These, perhaps more surprisingly, were also attributed to cigarette smoking.
The researchers at Atlanta looked at 345,962 cancer deaths amongst adults in the US who were aged 35 years and over. By studying the backgrounds of the people, they deduced that half of them had died because of an association with smoking.
How was the study carried out?
The study used a standard formula to calculate the exact fraction of cases of particular types of cancer that would not have occurred if the person had not smoked. The researchers then took data from national surveys and interviews which questioned people about their personal health history and smoking habits.
This data was adjusted for age, race, alcohol use and even level of education. This allowed the researchers to accurately estimate the number of deaths from smoking, based on smoking habits and cases of cancer deaths.
What other cancers are affected by smoking?
As well as half of deaths for 12 different cancers relating to smoking, the study showed that smoking can also be attributed to 17 percent of kidney cancer deaths, 20 percent of stomach cancer deaths, 22 percent of cervical cancer deaths and 24 percent of liver and bile duct cancer deaths in 2011.
Are there any flaws in the study?
There are flaws with the Atlanta study however. It does not take into account people’s personal accounts when recalling their smoking habits. People tend to underplay the amount they smoke, so in fact the estimated deaths from smoking in the study could be much higher.
The survey and study also took more educated and less racially diverse participants than the U.S. population. The researchers do acknowledge in the JAMA Internal Medicine however.
There is also the question of second-hand smoking which was not addressed in the study. There was no data available on this so the study could not process this information in relation to cancer deaths.
Lead study author Rebecca Siegel, a researcher at the American Cancer Society in Atlanta, realises there is a battle ahead regarding smoking:
“The bottom line is that while we’ve made a lot of progress against the tobacco epidemic in the United States, there’s still much work to do.”
How do e-cigarettes impact the study?
Many health experts are concerned about the rise in use of e-cigarettes. Smoking alternatives such as cigar and vaping has increased in the last couple of years.
Siegel says that smoking alternatives has doubled from the equivalent of 15.2 billion cigarettes in 2000 to the equivalent of 33.8 billion cigarettes in 2011.
“While smoking prevalence continues to slowly decline, the use of alternative tobacco products is on the rise,” she said.
And the worrying problem is that school children are amongst the highest users of e-cigarettes:
“Although we can’t know exactly how many people are not starting to smoke cigarettes because they are using other tobacco products, e-cigarettes are now the most common form of tobacco use among high school students,” Siegel said.
In Europe, laws are currently being passed to stop people from smoking e-cigarettes in bars and clubs, despite there being no evidence to support that smoking them encourages a transfer onto the real thing.
There is evidence to suggest that smoking e-cigarettes could be a factor in the decline of lung cancer cases. However, Dr. Michael Ong, author of a tobacco cessation editorial which accompanied the study, and a researcher at the University of California, Los Angeles and the Veterans Affairs Greater Los Angeles HealthCare System said:
“But most of all lung cancer deaths are still attributable to smoking, and lung cancer makes up the largest cause of cancer-related mortality.”
Giving up smoking
Giving up smoking has proven to be extremely difficult, and simply showing people the facts about their increased risks of contracting cancer does not seem to be motivating enough to help them quit.
In the study, the researchers followed more than 3,000 smokers for one year after they had been screened for their lung cancer.
They all received different types of support in relation to quitting smoking. Those who had counselling or prescriptions for smoking-cessation drugs were 40 percent more likely to quit, whilst those who received follow-up care which monitored their progress were 46 percent more likely to stop smoking.
“Smokers face physical, environmental and social barriers to quitting,” lead study author Elyse Park, a researcher at Massachusetts General Hospital in Boston, said by email.
“Primary care providers can assist smokers, particularly smokers with a heavy smoking history, to boost their confidence and obtain the counselling and medication support that can help them improve their odds of successful quitting.”