Tobacco smoking attributed to more than 1 million cancer deaths in seven countries
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Key takeaways:
- A total of 1.9 million cancer deaths were attributable to alcohol, tobacco smoking, excess body weight and HPV infections.
- Smoking tobacco resulted in 20.8 million years of life lost among patients with cancer.
Among four preventable risk factors for cancer mortality, smoking tobacco resulted in the most deaths and years of life lost in seven countries, according to data published in eClinicalMedicine.
“We concluded that smoking, alcohol, overweight/obesity and HPV infections are the drivers of almost 2 million deaths from cancer across seven countries every year,” Harriet Rumgay, PhD, postdoctoral scientist of cancer surveillance at the WHO International Agency for Research on Cancer, told Healio. “These findings highlight the key role of primary prevention to reduce cancer mortality by saving millions of lives from preventable cancers.”
In a population-based study, Rumgay and colleagues assessed the estimated number of deaths and years of life lost (YLLs) to cancer in 2020 caused by alcohol consumption, tobacco smoking, overweight/obesity and HPV infections in Brazil, Russia, India, China, South Africa, the U.K. and the U.S. to evaluate the impact of these factors in patients with cancer across the world.
Researchers determined the number and age-standardized YLL rates (ASYR) through life tables.
When evaluating each risk factor in all seven countries, tobacco smoking contributed to the most cancer deaths (1.3 million) in 2020, followed by alcohol consumption (326,300 deaths), excess body weight (208,000 deaths) and HPV infection (190,400 deaths) for a total of 1.9 million deaths.
Researchers further found that tobacco smoking was linked to the highest estimated YLLs out of the four factors, at 20.8 million. The second highest estimate of premature deaths was due to alcohol consumption (5.9 million), followed by HPV infection (4 million) and excess body weight (3.1 million).
“We wanted to stress the continued impact of tobacco smoking on the burden of cancer, as we found that of the 2 million deaths from cancer due to the four risk factors in the seven countries, smoking was the driver of 1.3 million,” Rumgay told Healio. “Of the 30 million years of life lost from cancer due to the four risk factors, tobacco smoking had the biggest impact by far, leading to 20.8 million years of life lost. Our findings show that tobacco control should still be a priority even in countries where smoking rates have fallen, like the U.S. and U.K., as huge numbers of deaths from cancer due to tobacco are still emerging today.”
ASYRs between countries
China had the greatest ASYR from cancer attributable to alcohol (351.4 YLLs per 100,000 population; 95% CI, 194.5-519.2) and tobacco smoking (1,159.9 YLLs per 100,000 population; 95% CI, 950.6-1,361.8), according to researchers.
For alcohol consumption, the U.S. (113.5 YLLs per 100,000; 95% CI, 69.6-157.1) and India (115.4 YLLs per 100,000; 95% CI, 49.7-172.7) had the lowest ASYRs. Researchers also found that India was the country with the smallest ASYR from cancer caused by smoking (262.7 YYLs per 100,000 population; 95% CI, 192.7-337.5).
Although the U.S. had a lower ASYR due to alcohol, it had one of the highest ASYRs due to excess body weight (369.4 YLLs per 100,000 population; 95% CI, 299.6-433.6) alongside Russia (385.1 YLLs per 100,000 population; 95% CI, 280.6-481.2).
Lastly, South Africa had the greatest ASYR attributable to an HPV infection (457.1 YYLs per 100,000 population; 95% CI, 453.3-462.6), whereas the U.S. had the lowest rate (84.5 YYLs per 100,000 population; 95% CI, 80.8-87.2), according to researchers.
ASYRs by gender
Dividing ASYRs by gender, researchers found that men had increased rates for alcohol consumption and smoking vs. women.
“In China, India and Russia, rates of years of life lost to tobacco smoking and alcohol were up to nine times higher in men than women,” Rumgay told Healio. “This is because smoking and drinking rates tend to be higher in men. But the variation in rates was much smaller in the U.K. and U.S. where alcohol consumption and tobacco smoking among women have increased to similar rates to those of men.”
Notably, more YLLs related to HPV infections and excess body weight were observed in women vs. men.
“In South Africa and India, HPV infections led to particularly high rates of years of life lost among women,” Rumgay told Healio. “Specifically, rates were 60 times higher in women than men in South Africa, and 11 times higher in India, largely due to the high burden of cervical cancer in the two countries. Similarly, higher numbers of years of life lost due to excess body weight among women could be explained by a higher prevalence of excess body weight among women than men, and a larger number of female-specific cancers associated with excess body weight than male cancers.”
YLLs by cancer type
In six of the seven countries, lung cancer was connected to a majority of premature deaths related to tobacco smoking. In India, head and neck cancers contributed to most premature deaths related to this risk factor among men, whereas gynecological cancers contributed to the most premature deaths among women.
In every country, premature death attributable to excess body weight was primarily found among women with breast cancer and men with colorectal cancer and other gastrointestinal cancers, according to researchers.
Further, in every country, a majority of HPV-related premature deaths were found in men with head and neck cancer and women with cervical cancer.
When evaluating cancer types of those who experienced premature deaths due to alcohol consumption, researchers found different results based on the country and sex of the individual.
Among men in China and the U.S., liver cancer was behind 44.7% and 40.1% of the premature deaths related to alcohol. In the U.K., the cancer that contributed to 36.5% of YLLs among men was colorectal cancer. For men in India, Brazil and Russia, 34.5% to 53.6% of the YLLs were linked to head and neck cancer.
Among women, esophageal cancer and breast cancer both contributed to a great proportion of premature deaths attributable to alcohol consumption in the assessed countries.
Real-world impact, future studies
When asked how these findings will impact clinicians, Rumgay said she hopes they will inspire improvements to care for patients with cancer who have one or more of the studied risk factors.
“We hope that clinicians can use our findings to find support and encouragement for primary prevention activities in their networks,” she said. “Tobacco cessation services are essential to help people quit smoking, and giving patients advice on the benefits of reducing alcohol intake and maintaining a healthy weight with useful tips to achieve these is invaluable. We also know that HPV vaccination prevents cervical cancer, and cervical screening is a major way of eliminating cervical cancer, yet access to both the HPV vaccine and cervical screening remain a challenge in many populations.
“As our study looked at deaths from cancer, some of the deaths from cancer we estimated could have potentially been avoided if they had been diagnosed at an earlier stage and/or had better access to curative treatment,” Rumgay added. “Improving earlier detection of cancer and access to quality treatment are further ways that clinicians can contribute to reducing the number of people dying unnecessarily from cancer.”
Research to come will look at how alcohol consumption, smoking, overweight/obesity and HPV infections impact society, and Rumgay hopes to include more countries in future analyses.
“In our future studies, we plan to carry out more focused analyses of the four risk factors and really define the impact on society of deaths from preventable cancers,” Rumgay told Healio. “This could be through linking our findings on cancer deaths due to risk factors with further indicators such as the direct costs of treatment or indirect costs such as loss of income, similar to other work we have previously published on the economic impact of cancer deaths due to alcohol consumption in Europe.
“We would also like to expand our analysis to more countries and further risk factors that we know have a large impact on the population, such as viral hepatitis or other forms of tobacco,” she added. “We are also developing ways to measure the number of people dying from cancer that could have been avoided through improved access to curative treatment.”
Reference:
- 7 countries, 1.3 million lives lost — the devastating impact of tobacco revealed. https://news.cancerresearchuk.org/2023/11/16/1-3-million-lives-lost-to-tobacco/. Published Nov. 16, 2023. Accessed Nov. 20, 2023.
For more information:
Harriet Rumgay, BSc, PhD, can be reached at rumgayh@iarc.who.int.