Bad diet, inactivity, smoking and drinking alcohol – all are among the causes of up to 90 percent of cancers, according to a new analysis that stresses how many cases of cancer are under our control.
This paper, published in Nature, is in stark opposition to the paper out earlier this year. Published in Science, that paper found that the majority of cancer cases were caused by “bad luck,” our cells going awry without much people could do to control them. At that time, we pointed out some key flaws with their analysis.
This study used the same premise and a lot of the same data as the Science article to reach a different conclusion: lifestyle makes a difference when it comes to cancer risk.
Here at AICR, where we focus on how diet, physical activity and body fat link to cancer, a wide and consistent body of evidence shows that these factors make a difference. One third of the most common cancers can be prevented with diet, staying lean, and being active.
Add in not smoking, using sunscreen and other risk factors, and the number goes up even more.
In the Nature paper, the authors found that the factors we can’t control – the intrinsic factors – only influence less than 10 to 30 percent of the most common cancers. The other causes of cancer, the extrinsic factors that are under our control, are responsible for more than 70 to 90 percent of the most common cancer types.
For example, using different types of evidence, the paper finds that about seven of every ten cases of colorectal cancers are due to such lifestyle factors as eating an unhealthy diet, smoking, drinking alcohol and being overweight.
Like the previous researchers, the authors of the Nature article looked at how cancer risk relates to the division of stem cells. These cells can develop into different types of cells in our body and the theory is, if they form mutations during these division it can lead to cancer. But they also looked at population studies, along with research that analyzed cancer mutations.
The work was supported by grants from the National Cancer Institute.