URBANA, IL (Chambana Today) — Lung cancer has long carried the label of a smoker’s disease, but that picture is increasingly incomplete. Between 10 and 20 percent of lung cancer patients are non-smokers, and researchers are working to understand why.

Jun Zhang, MD, PhD, a thoracic oncologist and vice president of oncology research at the OSF HealthCare Cancer Institute, says several factors beyond cigarettes are driving diagnoses. Here are three factors.

Cooking fumes

High-heat cooking, particularly with animal fats in a wok, can produce fumes that are inhaled and may cause lung damage over time. The World Health Organization reports that roughly 11 percent of lung cancer deaths in adults are linked to carcinogens from household air pollution caused by solid fuels or kerosene used for cooking.

“This is one of the reasons there’s a higher incidence among Asian people, because of cooking style,” Dr. Zhang said. “The way we cook delicious food is using the really hot wok. Especially if the cooking involves using animal fat, it can create droplets that can be inhaled and cause problems.”

Secondhand smoke

There is no safe level of exposure to secondhand smoke, according to the CDC, which reports that it causes more than 7,300 lung cancer deaths each year in American adults who don’t smoke and raises the risk of lung cancer in non-smokers by 20 to 30 percent.

“Whether it’s a parent smoking or a coworker smoking, this leads to indoor air pollution,” Dr. Zhang said.

Genetic predispositions

Family history is the single largest risk factor for lung cancer among non-smokers, accounting for roughly 25 percent of attributable risk. Variants in genes like EGFR and STK11 can increase susceptibility, and Dr. Zhang says advances in genetic testing and artificial intelligence are making these variants easier to identify.

What to do if you’re concerned

Current low-dose CT screening guidelines require patients to be at least 50 years old with a significant smoking history, a criteria that exclude many at-risk non-smokers. Dr. Zhang says those guidelines may need to expand, particularly for Asian women.

If you have a lingering cough lasting several weeks, he recommends starting with your primary care provider and advocating for a CT scan if common causes are ruled out.