An ounce of prevention, and billions in savings

A recent study shows that almost half of all global cancer deaths are due to preventable risk factors, with smoking, alcohol use, and obesity making the greatest contribution. Finding ways to reduce these risk factors could decrease cancer rates and mortality, and help alleviate the enormous personal and economic toll cancer takes on society — in Canada and around the world.

First published on 20 August 2022 in The Lancet, this study is the first to estimate how a long list of risk factors contribute to cancer deaths and ill health across age groups, for both sexes, and over time. It was funded by the Bill & Melinda Gates Foundation and conducted by the Global Burden of Disease (GBD) Cancer Risk Factors Collaborators at the University of Washington’s Institute for Health Metrics and Evaluation (IHME).

The landmark study showed that, in 2019, half of all male deaths from cancer, and more than one-third in women, were due to preventable risk factors, including tobacco and alcohol use, unhealthy diets, unsafe sex and workplace exposure to harmful products, such as asbestos. From 2010 to 2019, global cancer deaths caused by these preventable risk factors increased by about 20 percent, with excess weight accounting for the largest percentage of increase, particularly in lower-income nations.

According to Dr. Christopher Murray, Director of the IHME and an author of the study, “Our findings can help policymakers and researchers identify key risk factors that could be targeted in efforts to reduce deaths and ill health from cancer regionally, nationally and globally.”

Canadian scientist Dr. Justin Lang is a co-lead author of the study and an Epidemiologist working in the Applied Research Division, Centre for Surveillance and Applied Research at the Public Health Agency of Canada (PHAC).

“In Canada, nearly 50 percent of the total cancer burden is attributable to the risk factors measured in this study, with exposure to most of them being preventable,” he explained in an email to Research Money.

“The study’s results suggest that Canadians can play a big role in preventing future cancer burden. There is a need to focus on healthy public policy and action that ensures that everyone has an equal opportunity to live a healthy active lifestyle, where people can live long healthy lives without the risk of developing cancer.”

Cancer-related costs could be reduced

In Canada, cancer-related costs totalled $26.2 billion in 2021, with health system costs of about $18.4 billion and $7.8 billion borne by patients and families. Interventions targeting preventable cancer risk factors could decrease Canadian cancer management costs by billions of dollars.

A team of Canadian researchers recently released estimates of the economic impact of interventions on various cancer risk factors, such as smoking and obesity. They looked at how theoretical interventions targeting preventable risk factors implemented in 2020 would reduce the risk of cancer 12 years later in 2032 and the associated potential savings.

They predicted that smoking will be the largest contributor to cancer-related costs in Canada, with a cost of $44.4 billion between 2032 and 2044. They also estimated that $3.3 billion of that cost could be avoided with a 30% reduction in smoking prevalence by 2022.

Dr. Lang and his research team concur. “Our study found that the most important potentially modifiable risk factor for cancer in Canada in 2019 was tobacco use, which made up roughly a quarter of the total cancer burden that year. Tobacco use was followed by high body-mass index and alcohol use, each estimated to be attributable to roughly 6 percent of the total cancer burden in Canada in 2019 for both sexes combined.”

Canada has had good success in reducing rates of smoking, which went from about 50 percent of Canadians in 1964 to just 11 percent in 2020. This steady decline is thanks to aggressive anti-smoking policies, which ranged from increased tobacco taxes and graphic warnings, to advertising and sponsorship bans, and smoking bans in restaurants and bars.

The Government of Canada aims to continue to decrease tobacco use in Canada to less than 5 percent by the year 2035. However, new challenges related to e-cigarettes (vaping), the legalization of cannabis, and contraband tobacco will require innovative policies to decrease smoking-related cancers in Canada.

Food policies and parks may improve outcomes

Following smoking, the next highest preventable cancer management costs in Canada are associated with inadequate physical activity and excess body weight, accounting for $10.7 billion ($2.7 billion preventable) and $9.8 billion ($3.2 billion preventable), respectively.

According to Dr. Lang, “Recently, there have been many efforts in Canada and internationally to research and invest in creating healthy built environments. Creating neighbourhoods that promote healthy living through walkable areas and access to green spaces and parks could be one solution to promote healthy behaviours and prevent future cancers.”

Meanwhile, Canada’s Healthy Eating Strategy is working to address increasing rates of obesity and diet-related chronic disease in the country. So far, the federal government has banned trans fats and updated the Canada Food Guide to include more fruits and vegetables in its recommended daily intake.

However, the government has failed to pass legislation restricting marketing of junk food to children in Canada, where 90 percent of food and drink ads children see on TV and online are for ultra-processed options. Bill S-228, also known as the Child Health Protection Act, died in the Senate in 2019, in large part due to industry lobbying.

Quebec has had legislation since 1980 that prohibits commercial advertising of unhealthy food and beverages to children under 13. The Canadian Heart & Stroke Foundation says that this has helped Quebec achieve the country’s highest fruit and vegetable consumption levels, as well as the lowest obesity rates, among children ages 6-11.

On June 30, 2022, the federal government did announce new mandatory front-of-package labelling (FoPL) by 2026 for foods and beverages that are high in sodium, sugars, or saturated fat. Beyond guiding healthy choices, mandatory labels in Canada are expected to incentivize companies to develop healthier products.

Canada joins countries like Chile and Mexico, which have introduced similar labelling. An evaluation of Chile's FoPL found a 25 percent decline in sugary drink purchases after 18 months, and 37 percent of Chileans agreed that the labels led them to make changes to their food choices.

Since 2005, the UK has had its own voluntary “traffic-light” FoPL system, with red, green, and amber options, according to the specific implications for health. The majority of processed foods now use these labels, which have helped consumers make informed choices, and encouraged manufacturers to improve the nutritional quality of their products.

According to the World Health Organization, taxing sugary drinks can also lower consumption and reduce obesity. In fact, more than 45 jurisdictions around the world have already instituted a soda tax, including eight cities in the United States, as well as many countries in Europe, South America and the Middle East.

Until a few weeks ago, that list did not include Canada. On September 1, 2022, Newfoundland and Labrador implemented Canada’s first tax on sugar-sweetened beverages. The new tax is projected to generate $9 million in annual revenue, which will go towards physical activity and prenatal infant nutrition initiatives, and school food programs.

New alcohol guidelines proposed

Another beverage highlighted by recent health research has been alcohol. In 1988 it was classified as a human carcinogen by the International Agency for Research on Cancer (IARC). By 2007, the international body stated that no level of alcohol consumption was proved to be safe, when considering cancer risks.

In Canada, a 2019 study found that if more Canadians limit their alcohol intake, about 44,300 cancer cases could be prevented by 2042. Just like Dr. Lang’s study, it said that strategies that reduce alcohol consumption can have an impact on reducing the cancer burden in Canada.

This summer, Health Canada proposed new alcohol consumption guidelines, suggesting no more than two drinks per week. This is a significant change from the current guidelines, which recommend no more than 10 drinks per week for women and 15 drinks per week for men.

The new guidelines were based on the latest evidence and published in a recent report by the Canadian Centre on Substance Use and Addiction (CCSA). They are now conducting a six-week online public consultation on the new drinking guidelines, which the public can participate in until 23 September 2022.

Still many unknowns

While Canada’s policies on alcohol, smoking and healthy eating continue to evolve, Dr. Lang says, “It’s difficult to know exactly which policy changes would have the largest impact on preventing cancer in Canada. That is certainly the million dollar question.

“Changes in population-level risk factor exposures and its impact on Canada’s future cancer burden will likely take many years to really understand.”

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