Study: Half of cancer cases are caused by six lifestyle factors

A new study has found that one in four cancer cases and half of all deaths could be avoided if a set of specific factors in daily life were avoided.

American researchers found that nearly half of cancer deaths in the United States are attributed to six decisions people make in their daily lives, such as smoking, drinking alcohol, and not exercising enough.

They looked at the number of cases and deaths, and whether they were linked to “modifiable risk factors,” including:

- Cigarette smoking (current and past)

- Passive smoking

- Excess body weight

- Alcohol consumption

- Consumption of red and processed meat

- Low consumption of fruits, vegetables, dietary fiber and dietary calcium

- Physical inactivity

- Ultraviolet (UV) rays

- Infection with Epstein-Barr virus (EBV), Helicobacter pylori, hepatitis B virus (HBV), hepatitis C virus (HCV), human herpes virus 8, human immunodeficiency virus (HIV), and human papillomavirus (HPV).

The team found that 40% of all cases (713,340) and about half of all deaths (262,120) could be attributed to all of these factors.

The analysis showed that smoking had the highest proportion of cases attributed to it, at 19.3% (or 344,070).

Cigarettes contributed to 56% (206,550 of 368,600) of all preventable cancers in men, and 39.9% (137,520 of 344,740) in women.

Being overweight was the second largest risk factor (7.6%), followed by drinking alcohol (5.4%).

The researchers did not specify the amount of alcohol consumed by the people in the study. However, the US Centers for Disease Control defines regular alcohol use as two drinks per day for men and one drink per day for women.

However, they recommend drinking less, and say the safest bet is to avoid drinking altogether.

This is followed by exposure to ultraviolet radiation (4.6%) and physical inactivity (3.1%).

When it came to cancer type, the proportion of cases attributable to potentially modifiable risk factors ranged from 100% for cervical cancer and Kaposi's sarcoma (a cancer that forms in the lining of blood vessels and lymph vessels), to 4.9% for ovarian cancer.

The percentage exceeded 50% for 19 out of 30 types of cancer evaluated.

About 3.5% of all cancer cases and deaths are attributed to infection, with HPV contributing the largest proportion of cases (1.8%) and deaths (1.2%).

The results highlight the importance of raising awareness about these risk factors, to reduce cancer cases and deaths.

In fact, not every type of cancer can be easily attributed to risk factors such as those outlined in the study.

This study focused on the United States, while there were 18.1 million new cases of cancer worldwide in 2020, according to Cancer Research UK (CRUK), so it is an international problem.

As such, the study was not comprehensive and accurate enough, requiring further research, particularly in relation to the four most common types of cancer occurring worldwide - breast, lung, bowel and prostate - which account for more than four in 10 cases, especially in light of Cancer Research UK (CRUK) estimating that there will be 28 million new cancer cases each year by 2040.