Lung cancer is still widely associated with older, heavy smokers. Yet researchers are increasingly confronting a troubling trend: more young people who have never smoked, particularly women, are being diagnosed with the disease. The rise comes despite falling smoking rates, and its causes remain unclear.
A new U.S. study has suggested a surprising possible explanation. Young lung cancer patients who had never smoked reported healthier-than-average diets, with greater consumption of fruit, vegetables and whole grains.
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More young people who never smoked have been diagnosed with lung cancer in recent years
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Researchers stress that the foods themselves are not considered harmful, but are examining whether pesticide residues on conventionally grown produce may contribute to the lung cancer risk.
The research, reported by ScienceDaily, was presented at the annual meeting of the American Association for Cancer Research. The researchers said pesticide exposure could potentially explain at least some of their findings, but stressed that the possible connection requires further investigation.
Conventionally grown fruit, vegetables and whole grains generally contain more pesticide residues than dairy products, meat and processed foods, the researchers noted. They also pointed to previous studies indicating that agricultural workers exposed for years to certain pesticides may face an elevated risk of lung cancer.
“There are data from studies among agricultural workers suggesting that prolonged exposure to certain types of pesticides may increase the risk of lung cancer,” said Dr. Haim Zilberman, head of the lung and thoracic tumors field at the Oncology and Hematology Center at Emek Medical Center, part of Clalit Health Services.
“It is possible that such exposure also contributes to the disease among some younger patients, but it is important to emphasize that the current study included a relatively small number of participants. Larger studies are needed to determine whether such a connection actually exists.”
What did the researchers examine?
The study included 187 people diagnosed with lung cancer before age 50 through the Epidemiology of Young Lung Cancer project. Participants were asked to provide information about their diets, smoking history, demographic background and disease characteristics.
Most had never smoked, and many were diagnosed with a form of lung cancer that is biologically different from the type commonly found among smokers. An earlier study by the same research group suggested that lung tumors developing in younger patients may represent distinct subtypes of the disease.
Study participants reported healthier-than-average diets
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To assess diet quality, the researchers used the Healthy Eating Index, which assigns a score from 1 to 100 based on U.S. dietary guidelines. The participants had an average score of 65, compared with an average of 57 among the broader U.S. population. They also reported eating more fruit, vegetables and whole grains.
On average, participants consumed 4.3 servings of dark green vegetables and legumes per day and 3.9 servings of whole grains. By comparison, average daily consumption among the general population stood at 3.6 servings of green vegetables and legumes and 2.6 servings of whole grains.
Women appeared to face a higher risk
Another notable finding was the difference between women and men. Women under 50 who had never smoked were diagnosed with lung cancer more frequently than men in the same age group. The women also reported healthier diets on average, including higher consumption of fruit, vegetables and whole grains.
Researchers are examining whether pesticide exposure is linked to an increased risk
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Dr. Zilberman stressed that pesticides are only one of several possible explanations being examined. “Other risk factors may be linked to the development of lung cancer among people who have never smoked, including exposure to environmental pollutants, harmful substances in the workplace, radon gas, which is a naturally occurring radioactive gas that can accumulate in homes and buildings, and secondhand smoke,” he said.
The researchers also noted important limitations: pesticide levels were not measured directly in participants, and exposure was instead estimated using existing data on residue levels across different food groups.
Dr. Haim ZilbermanPhoto: PrivateThe next stage of the research will involve directly measuring pesticide levels in patients’ blood and urine samples to determine whether specific chemicals may be associated with an increased risk of lung cancer.
For now, Zilberman said, the findings do not justify changing dietary recommendations. “The important message is that even young people who lead healthy lifestyles should pay attention to their bodies and should not ignore unusual symptoms,” he said.
“A new cough that persists without an explanation, unintentional weight loss or other continuing symptoms are reasons to consult a doctor and undergo an examination.”