By Shelley Wood
April 20, 2012 (Dubai, United Arab Emirates) — An international study is confirming what many cardiologists have known for a while–many smokers around the globe know that smoking can cause lung cancer, but far fewer are aware that their habit has adverse effects on the heart. Even more striking, smokers were largely unaware that secondhand smoke increases the risk of heart disease and stroke among nonsmokers.
The new numbers, unveiled by Dr Geoffrey T Fong (University of Waterloo, ON) at the World Congress of Cardiology (WCC) 2012, come from the International Tobacco Control (ITC) Policy Evaluation and the Global Tobacco Surveillance System (GTSS). Both, Fong noted to heartwire , provide strikingly similar snapshots of smokers’ perceptions of their own disease risk.
“We know the science–that smoking or tobacco use and secondhand smoke are significant causes of CVD, as well as lung cancer and other forms of cancer–and then the question becomes, do people know the facts about the relationship between tobacco use, secondhand smoke, and CVD, and to what extent does this differ across different countries?” Fong told heartwire . “This is important because well-informed people are more capable of making a decision about tobacco use: for those who don’t use it, will they start? or for those who are using tobacco, would it give them reason to quit?”
Smokers, Fong points out, are much more likely to die of heart disease than they are from lung cancer.
Unawareness Around the Globe
In both data sets, lack of awareness that smoking causes heart disease, or heart attacks, and stroke was highest in China, at over 70% for stroke and ranging from 46% to 62% for heart disease between the ITC and GTSS surveys. By contrast, lack of awareness that smoking causes lung cancer among Chinese smokers was under 20% in both data sets.
Other countries with striking unawareness of smoking’s effects on the heart (25% or higher) were the Netherlands, Bangladesh, Thailand, India, Russia, and Vietnam in at least one of the surveys, with ignorance about stroke even higher. And that lack of awareness did not reach zero even in countries where tobacco-control efforts have been in place for years. In France, for example, almost 14% of smokers surveyed said they were unaware that smoking could cause stroke, a number that reached 17% in New Zealand and Brazil.
Across all countries surveyed, smokers are more aware of the risks of lung cancer than they are about the risks of CVD.
“Generally speaking, in low- and middle-income countries, there is less awareness of the harms of tobacco generally, but even in higher-income countries, heart-attack awareness was not as good as you’d expect,” Fong said. “In the US, for example, where there have been 50 years of awareness campaigns, smoking is still by far the leading cause of death,” yet lack of awareness that smoking causes heart disease among US smokers surveyed was almost 13%, rising to 24% for stroke.
In every country surveyed by the ITC, lack of awareness among smokers that secondhand smoke could cause heart attacks was typically double the awareness that this kind of “passive” exposure could cause lung cancer. That number jumped even higher when the same question was asked of nonsmokers. In Vietnam, for example, 88% of nonsmokers said they did not believe or did not know that secondhand smoke could cause heart disease.
“Across all countries surveyed, smokers are more aware of the risks of lung cancer than they are about the risks of cardiovascular disease,” Fong said. “People’s knowledge that secondhand smoke exposure causes cardiovascular disease is alarming low compared with their knowledge that secondhand smoke causes lung cancer.”
Where There’s Doubt, There’s a Market
To heartwire , Fong drew an analogy with global warming, pointing out that “creation of doubt” has been a tobacco-company marketing strategy, which underscores the importance of collecting these kinds of data on people’s beliefs and knowledge.
“If the tobacco industry or those who would argue against tobacco-control policies are successful, then the knowledge of or belief in the proven science linking smoking and heart disease, stroke, and cancer will erode. And there are forces that want to erode that.”
Physicians need to be aware of these kinds of forces, Fong stressed, and step up their efforts to educate patients and to help smokers quit. His presentation included other data collected by the ITC showing that only 50% of US smokers who visited a doctor were advised to quit, a number that fell to 16% in France, and 7% in the Netherlands.
Of note, the Netherlands, once a leader in implementing smoke-free policies, has in recent years partially repealed smoke-free legislation and had announced plans to end government-supported antismoking media campaigns.
In Canada, the new budget announced by the ruling Conservative party includes axing $15 million from its antismoking media programs.
Yet a recent National Cancer Institute monograph also showed that mass media have a profound impact “on knowledge, awareness, belief, and motivation for quitting and actual quitting,” Fong said.
“The ITC project has also published numerous studies showing the effectiveness of warning labels,” Fong said, and these new data support ongoing efforts to have all tobacco-product packaging have large, visible labels that include graphics, he said.
Of note, few countries have implemented pictorial health warnings on tobacco products that inform smokers about the cardiovascular risks of tobacco use, and no country has used pictorial health warnings to remind smokers that secondhand smoke causes cardiovascular disease.
Dr Georges Saade (Lebanese University, Beirut), who spoke during a WCC press conference, noted that tobacco use and secondhand-smoke exposure are major causes of cardiovascular disease globally and account for approximately 10% of all cardiovascular deaths. He also cited a US Surgeon General’s report from 2010 noting that secondhand smoke increases the risk of acute coronary syndromes by 25% to 30%.