Researchers looked at colorectal cancer cases across 204 countries from 1990 to 2021 to understand how common it is and what causes it. They found that while wealthy countries have gotten better at treating the disease and reducing deaths, poorer countries are seeing more cases. The biggest risk factor they identified was not eating enough whole grains. The study shows that colorectal cancer is becoming more common globally, but the problem is worse in some parts of the world than others. Understanding these patterns can help doctors and public health officials focus on prevention and treatment where it’s needed most.

The Quick Take

  • What they studied: How common colorectal cancer is around the world, how many people die from it, and what lifestyle and health factors increase the risk of getting it.
  • Who participated: This wasn’t a study of individual people. Instead, researchers analyzed health data from 204 countries and territories, looking at trends over 31 years (1990-2021).
  • Key finding: Colorectal cancer cases more than doubled worldwide from 1990 to 2021, going from about 917,000 new cases to 2.2 million. However, death rates actually improved in wealthy countries, while poorer countries are struggling more with the disease.
  • What it means for you: If you live in a wealthy country, your healthcare system is getting better at preventing and treating colorectal cancer. But globally, colorectal cancer is becoming more common, especially in developing nations. Eating more whole grains and maintaining a healthy lifestyle may help reduce your personal risk.

The Research Details

This was a large analysis that combined health information from many different sources across 204 countries and territories. Researchers looked at data from 1990 to 2021 to track how colorectal cancer rates changed over time. They organized the information by age, sex, and how wealthy each region was (called the Socio-demographic Index). They also identified which risk factors—like diet, weight, and exercise habits—were most connected to colorectal cancer cases.

The researchers used a system called the Global Burden of Disease Study, which is like a worldwide health tracking system. They measured three main things: how many new cases appeared each year, how many people died, and how much the disease affected people’s quality of life (measured in something called DALYs, or disability-adjusted life years).

This type of analysis is powerful because it combines information from many countries and many years, giving us a big-picture view of health trends worldwide. However, it relies on data that countries report, which can vary in accuracy depending on how good each country’s health tracking system is.

Understanding global patterns of colorectal cancer helps doctors and governments know where to focus their efforts. By looking at 31 years of data, researchers can see whether the problem is getting better or worse. By identifying risk factors, they can tell people what lifestyle changes might help prevent the disease.

This study is based on data reported by countries worldwide, so the accuracy depends on how well each country tracks health information. Wealthier countries typically have better health records than poorer countries, which means the data might be more reliable for some regions than others. The researchers used established methods from the Global Burden of Disease Study, which is widely respected in public health. However, because this is an analysis of existing data rather than a new experiment, it can show us patterns but not prove that one thing directly causes another.

What the Results Show

The number of new colorectal cancer cases worldwide nearly doubled over 31 years, jumping from 916,583 cases in 1990 to 2,194,143 cases in 2021. When adjusted for population size, the rate went from 24.0 cases per 100,000 people to 25.6 per 100,000—a modest increase.

However, the story is different depending on where you live. Wealthy countries had the highest rates of colorectal cancer (40.5 cases per 100,000 people in 2021), while poorer countries had much lower rates (7.4 per 100,000). This difference might seem like good news for poor countries, but researchers think it’s actually because their healthcare systems don’t catch as many cases.

The good news is that death rates improved globally. The number of deaths per 100,000 people dropped from 15.6 in 1990 to 12.4 in 2021. This suggests that treatments are getting better. However, this improvement wasn’t equal everywhere—wealthy countries saw bigger improvements than poorer countries.

When measuring the overall impact on people’s health and quality of life, the global burden decreased from 357.3 to 283.2 per 100,000 people. Again, wealthy countries made more progress than developing nations.

The research identified that diet plays a major role in colorectal cancer risk. Specifically, not eating enough whole grains was the biggest dietary risk factor. Other important risk factors included being overweight, not exercising enough, smoking, and drinking too much alcohol. These are all things people can potentially change to reduce their risk.

This research confirms what scientists have suspected: colorectal cancer is becoming more common worldwide as countries develop and people adopt more Western lifestyles (which often include less whole grain consumption and more processed foods). The finding that wealthy countries have better survival rates aligns with previous research showing that access to screening and treatment makes a big difference. The focus on modifiable risk factors like diet echoes other studies showing that lifestyle changes can help prevent colorectal cancer.

This study analyzed existing health data rather than following people over time, so it can show us patterns but can’t prove that one thing directly causes another. The quality of data varies by country—wealthy nations have better health tracking systems, so their numbers are probably more accurate. Some poorer countries may have many undiagnosed cases that don’t show up in the data. Additionally, the study couldn’t account for all possible risk factors, only those with strong scientific evidence. Finally, because this is a global analysis, it may not apply to your specific situation, which depends on your individual health, genetics, and lifestyle.

The Bottom Line

Based on this research, here are evidence-based steps you can take: (1) Eat more whole grains—this was the strongest dietary factor identified, so aim to make at least half your grains whole grains. (2) Maintain a healthy weight through balanced eating and regular exercise. (3) Don’t smoke and limit alcohol. (4) If you’re over 45-50 (depending on your country’s guidelines), talk to your doctor about colorectal cancer screening. These recommendations have moderate to strong evidence behind them. Confidence level: Moderate to High for the importance of these factors, though individual results will vary.

Everyone should care about colorectal cancer prevention because it’s increasingly common worldwide. This is especially important if you’re over 50, have a family history of colorectal cancer, or live in a wealthy country where the disease is more common. People in developing countries should also be aware, as healthcare access improves and cases are likely to increase. However, if you’re young and have no risk factors, your immediate risk is lower, though prevention habits now can help protect you later.

Colorectal cancer typically develops slowly over many years, so lifestyle changes you make now may take 5-10 years or more to show their full benefit. However, eating more whole grains and exercising regularly have other health benefits you might notice within weeks to months. If you’re getting screening, it can catch cancer early when it’s most treatable, potentially preventing problems years in the future.

Want to Apply This Research?

  • Track your daily whole grain intake (aim for at least 3 servings per day) and weekly exercise minutes (aim for 150 minutes of moderate activity). Log these weekly to monitor your progress toward colorectal cancer risk reduction.
  • Set a specific goal like ‘Replace white bread with whole wheat bread’ or ‘Add oatmeal to breakfast 4 times per week.’ Use the app to remind you and track when you complete these changes. Start with one change, master it, then add another.
  • Create a monthly summary view showing your whole grain servings and exercise minutes. Set a reminder for annual colorectal cancer screening conversations with your doctor (if age-appropriate). Track any family history changes or health concerns that should be discussed with healthcare providers.

This research provides global health trends and identifies risk factors associated with colorectal cancer, but it cannot diagnose or predict individual risk. The findings suggest that diet, weight, exercise, and smoking are important factors, but individual risk depends on many factors including genetics, age, and personal health history. This information is not a substitute for medical advice. If you have concerns about colorectal cancer risk or symptoms, please consult with a healthcare provider. Screening recommendations vary by age and risk factors—talk to your doctor about what’s appropriate for you. This study analyzed data from 204 countries with varying data quality, so results may not apply equally to all populations.