Researchers from various countries, under the auspices of the International Agency for Research on Cancer (IARC), analyzed 19 million cases of 36 different types of cancer across 185 countries.
Researchers from France, Switzerland, Canada, Qatar, and Japan said their findings highlight the need for deeper investigation into modifiable risk factors for cancer. The team focused on 30 modifiable factors, including smoking, alcohol consumption, body mass index (BMI), and exposure to environmental pollutants.
What Did the Scientists Discover?
During their research, the scientists analyzed data from the GLOBOCAN network, managed by IARC. They found that in 2022, there were 18.7 million new cancer cases worldwide. Of these, 7.1 million cases—approximately 40 percent—were linked to modifiable risk factors.
Globally, infections were a leading cause of cancer, accounting for 11.5 percent of cases, as reported by Daily Mail.
HPV is responsible for nine out of ten cases of cervical and anal cancer. This virus can remain dormant for decades, increasing the risk of cancer later in life.
Hepatitis is associated with a high likelihood of liver, pancreatic, stomach, oral cavity, and thyroid cancers, as well as non-Hodgkin lymphoma. Meanwhile, the Epstein-Barr virus triggers lymphoma and certain forms of stomach cancer. The H. pylori bacterium can lead to stomach cancer even decades after initial infection.
Other major causes of cancer in women included lack of physical activity and high BMI.
The researchers also found that nearly half a million cases of lung cancer in women could have been prevented. Of these cases, 60.5 percent were caused by smoking, 27.5 percent by environmental pollution, and 12 percent by harmful occupational conditions.
Regarding breast cancer, 33 percent of cases were linked to a lack of physical activity, 29 percent to high BMI, and 18 percent to suboptimal breastfeeding. Previous studies have shown that short-term breastfeeding or its complete absence deprives women of natural protective mechanisms, increasing the risk of developing cancer.
The primary cause of cancer worldwide is smoking, which is linked to 23 percent of cases. This is followed by infections (9.1 percent) and alcohol consumption (4.6 percent).
In men, 1.3 million cases of lung cancer were attributed to modifiable risk factors. Smoking caused 69 percent of these cases, while 16 percent were due to environmental pollution and 15 percent to harmful working conditions.
The study was published in the journal Nature Medicine. The team ranked modifiable cancer risk factors across sexes and included occupational causes in their assessment.
Top 30 Modifiable Cancer Risk Factors
- Smoking
- Alcohol consumption
- High BMI
- Lack of physical activity
- Smokeless tobacco, such as chewing or snuff
- Suboptimal breastfeeding
- Air pollution
- Ultraviolet radiation
- Helicobacter pylori
- Human papillomavirus (HPV)
- Hepatitis B
- Hepatitis C
- Epstein-Barr virus
- Human herpesvirus 8
- Urogenital schistosomiasis (Schistosoma haematobium)
- Human T-cell lymphotropic virus
- Opisthorchiasis and clonorchiasis caused by foodborne liver parasites Opisthorchis viverrini and Clonorchis sinensis
- Asbestos
- Arsenic
- Benzene
- Beryllium
- Cadmium
- Chromium
- Diesel engine exhaust
- Formaldehyde
- Nickel
- Polycyclic aromatic hydrocarbons
- Silica
- Sulfuric acid
- Trichloroethylene
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