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Study Links Diet, Activity to Lung Cancer Risk

CancerWise - February 2008

Eating four or more servings of green salad each week as well as working outside in the yard or garden a couple of times a week may significantly lower the chance of developing lung cancer in smokers and nonsmokers, according to a recent study.

Significance of the results

"The results are exciting because the study is applicable to everyone, and it may have a positive impact on the 15% of people who are diagnosed with lung cancer who are non-smokers," says Michele Forman, Ph.D., lead author on the study and a professor in M. D. Anderson's Department of Epidemiology.

Forman adds that although this is a very preliminary analysis, the results give researchers important clues about how smokers and non-smokers might be able to reduce their risk of developing lung cancer.

Goal of the study

This study sought to determine if physical activity and diet have an impact on whether people develop lung cancer.

Forman says frequency of eating salad is a marker of vegetable consumption.

Gardening was chosen as a physical activity because a wide range of people can participate in it, and other physical activity did not appear to influence risk prediction. It is one of the few activities people with lung cancer report doing.

Primary results

The investigators found that physical activity like gardening reduced the risk of developing lung cancer by:

  • 45% in former smokers
  • 33% in smokers

Smokers who eat three servings or less of salad a week have double the chance of lung cancer compared to smokers who eat four or more salads weekly, according to the study results.

Research methods

Researchers used a food-frequency questionnaire for participants to report about their diets during the previous year in healthy patients or the year before diagnosis of lung cancer in patients.

Data was collected on:

  • Cancer patients a year prior to diagnosis
  • Cancer-free individuals a year prior to interview

Participants also were asked about physical activity, including sports and other forms of exercise, throughout their adult years.


These findings are part of an ongoing study that is examining several risk factors for lung cancer. It matches people being treated for lung cancer at M. D. Anderson with cancer-free people who are patients at Kelsey-Seybold Clinic, a private physician group in Houston.

More than 3,800 participants are involved in the study.

They are matched and grouped by:

  • Smoking status (current, former and never smokers)
  • Age
  • Gender
  • Ethnicity

The study identified these risk factors for lung cancer:

  • Exposure to secondhand smoke or dust
  • Family history of cancer
  • History of respiratory disease
  • History of smoking

What's next?

Forman says more research is needed on the connection between lifestyle and cancer.

"We do not know yet whether these habits of eating well and exercising are markers for other lifestyle factors that might be even more important, such as lack of alcohol consumption," she says. "We have a lot of puzzles in the picture yet to analyze."

– Adapted by Dawn Dorsey from an M. D. Anderson news release

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© 2015 The University of Texas MD Anderson Cancer Center