Three risk factors cause half of all cancer deaths

Smoking, drinking alcohol and being overweight are responsible for almost half of all cancer deaths worldwide, according to the largest study of its kind.

Cancer is the second leading cause of death globally, and exposure to these risk factors play a key role in the biology and burden of many cancer types.

Doctors do not know the exact causes of cancer, and not every case or death is avoidable, but now researchers at the University of Washington’s school of medicine have become the first to work out how risk factors contribute to cancer deaths globally.

Smoking, alcohol use, and a high body mass index (BMI) are the biggest contributors.

In total, these risk factors are responsible for nearly 4.45m cancer deaths a year, according to the findings published in the Lancet that used the Global Burden of Diseases, Injuries, and Risk Factors (GBD) 2019 study.

That represents 44.4% of all cancer deaths worldwide. Half of all male cancer deaths in 2019 (50.6%, or 2.88m) were due to these risk factors, compared with more than a third of all female cancer deaths (36.3%, or 1.58m).

“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, the 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.

The biggest cause of risk-attributable cancer deaths for both women and men globally was tracheal, bronchus and lung cancer. These account for 36.9% of all cancer deaths attributable to risk factors. This was followed by cervical cancer (17.9%), colon and rectum cancer (15.8%) and breast cancer (11%) in women. In men, it was colon and rectum cancer (13.3%), oesophageal cancer (9.7%) and stomach cancer (6.6%).

The five regions with the highest cancer death rates owing to risk factors were central Europe (82 deaths per 100,000 population), east Asia (69.8 per 100,000), high-income North America (66 per 100,000), southern Latin America (64.2 per 100,000) and western Europe (63.8 per 100,000).

Several other leading causes of death, including stroke, diabetes and the number one killer globally, coronary heart disease, have also been linked to smoking, drinking alcohol and being overweight.