Up to 40 percent of cancer cases are due to bad habits, a new study revealed.
Many individuals worry that chemicals and pollutions increase their risk of developing cancer. While the claim may have basis, the new study showed that a large percentage of cancers are secondary to lifestyle choices - something that is modifiable.
Healthy Lifestyle Means Lower Cancer Risk
The Department of Nutrition research fellow Mingyang Song and senior study author Edward Giovannucci, professor of nutrition and epidemiology at Harvard T.H. Chan School of Public Health, found that 20 percent to 40 percent of cancer cases and 50 percent of cancer deaths could have been prevented had the patients quit smoking, stopped heavy alcoholic consumption, maintained a healthy weight and regularly exercised.
For the study, the researchers gathered data from long-term studies of 140,000 health practitioners who provide health updates every two years. To analyze the data, the individuals were divided into two groups: healthy lifestyle group and non-healthy group.
Healthy lifestyle was defined as personal habits not known to cause cancer such as abstinence from smoking, limited alcohol consumption from one to two drinks daily, BMI range of 18.5 to 27.5 and moderate physical activity weekly.
Researchers also analyzed data for specific cancers and found that 82 percent of lung cancer cases could have been avoided in women and 78 percent in men. Colorectal risk could be reduced by 29 percent and 20 percent for women and men, respectively. Women have a lower risk of having breast cancer by 4 percent, while men have a lower risk of prostate cancer by 21 percent.
They found that when data is compared with the general population that has bad habits, the numbers go up to as much as 40 percent to 70 percent. While the study is limited to whites, the researchers believe that similar results would come out if applied to other ethnic groups.
Researchers acknowledged that their study does not encompass all forms of cancer, as they excluded brain, skin and lymphatic cancers which are most likely to be caused by environmental factors. Nonetheless, their study still highlights that cancer can be prevented by having a healthy lifestyle.
Healthy Lifestyle As Cancer Prevention
"We should not ignore the knowledge we already learned over the past decade, or the past 100 years," said Song. "We should use this knowledge to ... improve the current cancer prevention effort."
Shifting to healthier habits would greatly impact cancer development. Graham A. Colditz from the Washington University School of Medicine wrote a commentary on the study and agreed that indeed preventing cancer is possible - 80 percent to 90 percent of cancers caused by smoking and 60 percent of other lifestyle-related cancers can be avoided.
For the study results to translate into something meaningful for the society, stakeholders must take an active part.
"As a society, we need to avoid procrastination induced by thoughts that chance drives all cancer risk or that new medical discoveries are needed to make major gains against cancer, and instead we must embrace the opportunity to reduce our collective cancer toll by implementing effective prevention strategies and changing the way we live," wrote Colditz.
The study was published in JAMA Oncology on May 19.