A new study suggests younger adults who have never smoked but eat healthier-than-average diets may face an unexpectedly higher risk of developing lung cancer.
Announced on Monday, researchers from the USC Norris Comprehensive Cancer Center released findings they previously presented at the American Association for Cancer Research annual meeting in April. The research examined dietary patterns among people diagnosed with lung cancer before age 50 and found that many patients consumed more fruits, vegetables and whole grains than the average American, despite never smoking.
Researchers stressed that the study does not suggest healthy foods cause lung cancer. Instead, they believe pesticide residues found on conventionally grown produce and grains could represent an environmental factor that deserves closer investigation.
Lead investigator Jorge Nieva, a medical oncologist and lung cancer specialist at USC Norris, said the results surprised the research team. He said younger non-smokers who reported eating healthier diets than the general population appeared more likely to develop lung cancer, raising questions about whether an unidentified environmental exposure accompanies otherwise beneficial foods.
However, Nieva emphasized that researchers have not proven pesticides caused the cancers. He said the findings instead point toward an important hypothesis that future studies need to examine directly.
Lung cancer has long been linked to smoking, older age and men. The average age at diagnosis remains 71.
However, researchers said one group has moved in the opposite direction over recent decades. Lung cancer cases among non-smokers younger than 50 have increased even as smoking rates have declined steadily across the United States since the mid-1980s.
Read more: Breath Diagnostics adopts state-of-the-art mass spectrometer device for lung screening
Read more: Breath Diagnostics leaders promote their mission at Miami investment conference
Project enrolled 187 people
Women account for much of that increase. Researchers found women younger than 50 who never smoked developed lung cancer more often than men in the same age group.
Additionally, women participating in the study generally reported eating healthier diets than their male counterparts.
Scientists launched the Epidemiology of Young Lung Cancer Project to better understand why younger non-smokers are receiving lung cancer diagnoses. The project enrolled 187 people diagnosed with lung cancer by age 50.
Participants completed questionnaires covering their diets, smoking histories, demographic information and cancer diagnoses.
Most participants had never smoked. Researchers also found many developed forms of lung cancer that differ biologically from cancers typically associated with tobacco use.
Furthermore, investigators pointed to earlier work from the project supporting that distinction. A 2021 study from the Epidemiology of Young Lung Cancer Project and the Genomics of Young Lung Cancer Project found lung cancers diagnosed before age 40 represent distinct disease subtypes compared with cancers appearing later in life.
To evaluate diet quality, researchers compared participants’ eating habits with national dietary data using the Healthy Eating Index. The scoring system rates overall diet quality on a scale from one to 100.
The younger lung cancer patients achieved an average Healthy Eating Index score of 65. The average score for the broader U.S. population stands at 57.
Additionally, researchers found women generally earned higher Healthy Eating Index scores than men.
Read more: Breath Diagnostics leader speaks at lung cancer education event in Louisville
Read more: Breath Diagnostics advances pre-op pneumonia screening with FDA breakthrough designation
Study stopped short of measuring pesticide exposure directly
Participants also consumed more fruits, vegetables and whole grains than typical Americans.
On average, they reported eating 4.3 daily servings of dark green vegetables and legumes. The average American consumes 3.6 servings.
Meanwhile, participants averaged 3.9 daily servings of whole grains. The typical U.S. adult eats about 2.6 servings.
Researchers believe those dietary differences may provide clues rather than answers.
Nieva said conventionally grown fruits, vegetables and whole grains generally contain more pesticide residues than dairy products, meat and many processed foods. He added that previous research involving agricultural workers has linked long-term pesticide exposure with higher lung cancer rates, making pesticides a plausible area for further investigation.
However, the current study stopped short of measuring pesticide exposure directly.
Instead, researchers estimated participants’ potential exposure by combining reported diets with previously published information describing average pesticide residue levels across different food categories.
Consequently, the study cannot determine whether any individual participant actually encountered elevated pesticide levels.
Researchers also cannot identify which specific chemicals, if any, might influence lung cancer risk.
The next phase of the project aims to answer those questions.
Scientists plan to analyze blood and urine samples collected from patients to measure pesticide exposure directly. Those tests could identify whether certain pesticides appear more frequently in younger lung cancer patients than expected.
Additionally, researchers hope those measurements will clarify whether women experience different exposure patterns than men.
Nieva described the current findings as an early step rather than definitive evidence. He said researchers hope identifying potentially modifiable environmental factors could eventually improve lung cancer prevention strategies and guide future public health recommendations.
Read more: Prestigious medtech intelligence firm recognizes Breath Diagnostics for innovation
Read more: Breath Diagnostics completes install of advanced mass spectrometry system
Don’t stop eating fruit and vegetables
The investigators cautioned that people should not stop eating fruits, vegetables or whole grains because of the findings. Those foods remain widely associated with lower risks of heart disease, diabetes and many other chronic illnesses, while the proposed pesticide connection remains unproven.
However, the study adds another possible explanation for the growing number of lung cancer cases among younger adults who have never smoked. Researchers said that trend has become increasingly difficult to explain using traditional risk factors alone.
Additionally, researchers say identifying previously overlooked risk factors could reshape how physicians approach younger patients with persistent respiratory symptoms. Earlier diagnosis often gives patients more treatment options and improves outcomes.
Doctors currently diagnose lung cancer using imaging scans followed by tissue biopsies to confirm the disease. They could also identify genetic mutations that guide treatment. However, biopsies can prove invasive and expensive.
Those limitations have fueled efforts to develop faster, less invasive diagnostic tools that could identify cancer earlier or reduce the need for repeat procedures. Consequently, several companies are pursuing new approaches.
Breath Diagnostics Inc. is developing breath-based tests that analyze volatile organic compounds linked to disease, while Owlstone Medical Ltd. uses breath analysis technology to detect biomarkers associated with lung cancer and other conditions.
.
joseph@mugglehead.com
