Study: Smoking and other factors cause 4.45 million global cancer deaths each year

Scientists from the University of Washington’s School of Medicine have conducted a study on how risk factors contribute to cancer deaths and ill health globally, and it's been found that nearly half of all cancer-related fatalities globally are caused by risk factors like smoking, consuming alcohol, being overweight, and others.

Smoking, drinking alcohol, and having a high body mass index (BMI) are the main causes of cancer deaths. According to the study, risk factors cause roughly 4.45 million cancer deaths annually. That amounts to 44.4 percent of all cancer-related fatalities worldwide. Compared to more than a third of all female cancer deaths (36.3 percent, or 1.58m), estimated risk factors were the reason behind half of all male cancer deaths in 2019 (50.6 percent, or 2.88m).

“This study illustrates that the burden of cancer remains an important public health challenge that is growing in magnitude around the world,” said Dr. Christopher Murray, director of the Institute for Health Metrics and Evaluation (IHME) at the University of Washington’s School of Medicine and a co-senior author of the study.

Smoking: The leading risk factor for cancer

“Smoking continues to be the leading risk factor for cancer globally, with other substantial contributors to cancer burden varying. 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,” he further added.

The study indicated that the vast majority of cancer worldwide was caused by behavioral risk factors such as smoking, alcohol use, unsafe sex, and dietary risks, which account for 3.7 million fatalities. It also turned out that for both sexes, the leading risk factors for cancer deaths were smoking, followed by alcohol use, and high BMI.

Largest project of its kind

The study used the Global Burden of Diseases, Injuries and Risk Factors (GBD) study from 2019 to investigate how 34 behavioral, metabolic, environmental, and occupational risk factors influenced deaths and ill health due to 23 cancer types in 2019.

The cancer burden estimates were based on deaths and disability-adjusted life-years (DALYs), a measure of years of life lost to death and years lived with disability. The study found that risk variables included in the analysis were responsible for 105 million cancer-related DALYs worldwide in 2019 for both sexes, or 42 percent of all DALYs in that year.

Researchers found that for both sexes, the leading cause of risk-attributable cancer death was tracheal, bronchus, and lung cancer, which accounted for 36.9 percent of all cancer deaths attributable to risk factors. It was followed by colon and rectum cancer (13.3 percent), oesophageal cancer (9.7 percent) and stomach cancer (6.6 percent) in men, and cervical cancer (17.9 percent), colon and rectum cancer (15.8 percent), and breast cancer (11 percent) in women.

The results of the study were published in the journal The Lancet.