Health · Meta-analysis

Global cancer burden and key risk factors worldwide, 1980–2021

• Researchers analyzed cancer incidence, deaths, and disability across 204 countries over four decades, finding cancer caused 14.6% of all deaths globally in 2021.
• Women had higher rates of new cancers overall, but men died from cancer more often, with lung cancer leading in men and breast cancer in women.
• Tobacco was the biggest preventable risk factor for cancer in men, responsible for nearly 30% of cancer-related disability, followed by poor diet, alcohol, and air pollution.

Journal of Hematology & Oncology · 2024 — https://doi.org/10.1186/s13045-024-01640-8

Global burden of cancer and associated risk factors in 204 countries and territories, 1980–2021: a systematic analysis for the GBD 2021

What this study is about

Scientists wanted to know how much cancer affects people all around the world. Cancer is a disease where cells in the body grow out of control.

They looked at information from 204 countries and territories, covering the years 1980 to 2021. That's over 40 years of data.

They checked things like how many new cancer cases show up, how many people die from cancer, and how much cancer affects people's health over their lifetime. They also looked at what things in life (called "risk factors") make cancer more likely, like smoking or eating habits.

What they found

In 2021, cancer caused about 14.57% of all deaths worldwide. That means out of every 100 people who died, almost 15 died from cancer.

Cancer also caused about 8.8% of what scientists call "DALYs," which stands for a way of measuring lost healthy years of life, either from dying early or from living with sickness.

Women got cancer more often than men. But men died from cancer more often than women. The researchers said this shows that healthcare should treat men and women fairly, since the two groups face different risks.

A type of skin cancer called non-melanoma skin cancer was the most common type of cancer found in both men and women. But cancers of the digestive system (like the stomach or intestines) caused the most cancer deaths overall, about 39% of all cancer deaths.

Asia had the heaviest cancer burden, meaning the most cancer cases and deaths compared to other parts of the world.

For women, breast cancer was both the most common cancer and the one causing the most deaths.

For men, cancer of the windpipe, airways, and lungs was both the most common and deadliest.

Smoking tobacco was the biggest risk factor connected to cancer in men. It was linked to about 29% of the healthy years men lost because of cancer. Other risk factors linked to men's cancer included poor diet, drinking alcohol, and breathing polluted air, though these had smaller effects than smoking.

What it means for you

This study didn't test a cure or a treatment. It measured how big a problem cancer is around the world and pointed out which risk factors matter most.

The study suggests that tobacco use is strongly linked to cancer in men, which is why the researchers say governments should focus on rules that reduce smoking.

The study also suggests that cancer looks different depending on where you live and whether you're male or female. Because of this, the researchers say that health policies should be designed specifically for each country's situation, rather than using one plan for everywhere.

This doesn't tell you personally what to do, since it's a big-picture study about populations, not individual people. But it does show that things like avoiding tobacco, eating well, limiting alcohol, and breathing cleaner air are connected to lower cancer risk on a large scale, which is useful information for people who make health rules and guidelines.