Experts say that around half of all global cancer deaths are due to 34 risk factors. 

Smoking, alcohol use, high BMI, and other known risk factors were responsible for nearly 4.45 million global cancer deaths in 2019, according to new research. 

The study is the first to estimate how a comprehensive list of risk factors contribute to cancer deaths and ill health globally, regionally and nationally, across age groups, for both sexes, and over time.

Despite being the second leading cause of death worldwide after cardiovascular disease, to date most studies of cancer burden have analysed single risk factors globally or multiple risk factors in select countries.

“This study illustrates that the burden of cancer remains an important public health challenge that is growing in magnitude around the world. Smoking continues to be the leading risk factor for cancer globally, with other substantial contributors to cancer burden varying,” says 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. 

“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.” 

The authors investigated how 34 behavioural, metabolic, and environmental and occupational risk factors contributed to deaths and ill health due to 23 cancer types in 2019. 

Changes in cancer burden between 2010 and 2019 due to risk factors were also assessed. Estimates of cancer burden were based on mortality and disability-adjusted life-years (DALYs), a measure of years of life lost to death and years lived with disability.

In addition to 4.45 million cancer deaths which made up 44.4 per cent of all cancer deaths in 2019, risk factors included in the analysis accounted for 105 million cancer DALYs globally for both sexes in 2019 - 42.0 per cent of all DALYs in that year. 

Behavioural risk factors (such as tobacco use, alcohol use, unsafe sex, and dietary risks) were responsible for the vast majority of cancer burden globally, accounting for 3.7 million deaths and 87.8 million DALYs in 2019. 

Almost 2.88 million deaths in men (50.6 per cent of all male cancer deaths) could be attributed to the risk factors studied, compared to 1.58 million deaths in women (36.3 per cent of all female cancer deaths). 

The leading risk factors globally for cancer deaths and ill health for both sexes were smoking, followed by alcohol use and high BMI.

The leading cause of risk-attributable cancer death for both men and women globally was tracheal, bronchus, and lung cancer, which accounted for 36.9 per cent of all cancer deaths attributable to risk factors. 

This was followed by colon and rectum cancer (13.3 per cent), oesophageal cancer (9.7 per cent), and stomach cancer (6.6 per cent) in men, and cervical cancer (17.9 per cent), colon and rectum cancer (15.8 per cent), and breast cancer (11 per cent) in women.

More details are accessible here.