Smokers lack awareness of smoking-related cardiovascular risks

An international study has found that despite two decades of global tobacco control efforts, the message still is not getting through to enough smokers that smoking and second-hand smoke cause heart attack and stroke. 

Researchers at the University of Waterloo and the Global Tobacco Control Program at the U.S. Centers for Disease Control and Prevention (CDC) conducted the study, which is the largest of its kind.

Tobacco use is the leading preventable cause of disease and death worldwide. Up to two-thirds of people who smoke throughout their lives die from a smoking-caused disease, and lose more than a decade of life, on average.

The research team analyzed data from more than 240,000 adult smokers across 46 countries over two decades. While more than 90 per cent knew that smoking causes lung cancer, only about 80 per cent knew it causes heart disease or heart attack and 70 per cent knew it causes stroke. In several high-income countries - including Australia, Germany, England, the U.S., New Zealand, and Canada - fewer than half of adults who smoke knew that second-hand smoke causes heart disease or heart attack. China, a country of 300 million smokers, was among the countries where awareness was lowest.

Knowledge gaps about the major health effects of smoking and second-hand smoke are deeply concerning. The low awareness of the cardiovascular harms of smoking and second-hand smoke is particularly troubling given that smoking causes more than 2 million cardiovascular deaths worldwide each year. Increasing public awareness of these risks should be a greater public health priority." 

Dr. Janet Chung-Hall, Research Scientist, International Tobacco Control Policy Evaluation Project (ITC Project), Waterloo and lead author of the study

Across two decades, the study found almost no progress in knowledge of the health risks of smoking and second-hand smoke. Although knowledge about the cardiovascular risks of smoking and second-hand smoke increased in some countries, including Bangladesh, India, Thailand and Vietnam, knowledge of those second-hand smoke risks actually decreased in the majority of high-income countries studied, including Canada, the U.S., New Zealand, England, and Japan.

The study also examined knowledge about lung cancer, finding that although about 90 per cent knew that smoking causes lung cancer, fewer knew that secondhand smoke does, with little progress over time. 

"Knowledge is an important first step toward quitting smoking and protecting others from second-hand smoke," said Dr. Geoffrey T. Fong, Principal Investigator of the ITC Project and University Professor of Psychology and Public Health Sciences at Waterloo. "Our findings highlight the need for governments to implement stronger, sustained public education about the cardiovascular as well as cancer risks of smoking and second-hand smoke. Policies such as large pictorial warnings and sustained media campaigns can increase awareness, encouraging quitting among those who smoke and discouraging young people from starting to smoke." 

Those policies are part of the global tobacco control treaty, the WHO Framework Convention on Tobacco Control, to which more than 180 countries are signatories.

The study appears in BMJ Open.