How a Common Daily Activity Increases Lung Cancer Risk

Author: Jiang Yongyuan, Master's Degree in Internal Medicine, Third Military Medical University. Review | Pan Zhanhe, Chief Physician of the Oncology Department at Zhongshan Hospital Affiliated to Xiamen University, Deputy Chairman of the Oncology Science Popularization Professional Committee of the Fujian Anti-Cancer Association. Planning | Zhang Yinuo. Editor: Zhang Yinuo. Review | Xu Lai, Zhang Linlin. Source | Keping China WeChat Official Account. The cover image and the images inside the text are sourced from a copyright stock library. Reposting may lead to copyright disputes.

Title: How a Common Daily Activity Increases Lung Cancer Risk Introduction: Study highlights kitchen grease smoke's link to lung cancer risk for homemakers and chefs, with tips to reduce exposure. Keywords: ['public health', 'prevention'] Main text: When it comes to the risk factors for lung cancer, most people's first response is still smoking. Indeed, tobacco is the most clear and significant pathogenic factor globally. However, in research conducted over the past few decades, one question has gradually emerged—does long-term exposure to cooking oil fumes increase the risk of lung cancer? This issue deserves serious attention because it affects not just a few individuals. Whether it's family members cooking at home every day or chefs in professional kitchens, exposure to cooking fumes can become a long-term, recurring aspect of daily life. Understanding its mechanisms and risks is not to induce anxiety, but rather to more wisely protect oneself. Why does kitchen smoke increase the risk of lung cancer? After smoking was identified as a major risk factor, researchers noticed a phenomenon: in certain Asian populations, particularly among non-smoking women, the incidence of lung cancer cannot be fully explained by smoking. This suggests that there may be other long-term environmental exposure factors at play. A case-control study included 1,302 lung cancer cases and 1,302 healthy controls, all of whom were non-smoking Han Chinese women. The results indicated that the risk of lung cancer increased with both the duration and frequency of cooking; the risk in the highest exposure group was approximately 3.17 times greater compared to the lowest exposure group. Although the subjects of this study are predominantly female, the exposure mechanisms are not gender-specific. Any individual who spends extended periods in a high-temperature cooking oil fume environment—whether professional chefs or family members—could theoretically face similar risks. The key variables are not gender but rather the intensity and duration of exposure. During cooking, the oil temperature can often reach 250°C to 300°C. Under such high-temperature conditions, the cooking oil undergoes thermal decomposition reactions with the ingredients, releasing a complex mixture of aerosol particles. The cooking fumes contain not only fatty aerosols but also polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs), and various aldehyde compounds. A study compared the levels of PAHs produced by pan-frying and deep-frying. The results showed that the total amount of PAHs generated by deep-frying was approximately 1.3 times higher than that of regular pan-frying, with the content of the representative carcinogen benzo[a]pyrene being about 10.9 times greater. The overall toxic equivalency concentration was around 2.2 times that of pan-frying. Three-ring and four-ring PAHs were identified as the main components, while high molecular weight PAHs were found to be more attached to particulate matter, making them more likely to enter the lower respiratory tract when inhaled. The exposure levels in a real home environment are also worthy of attention. A study on the cooking processes in Chinese households showed that under normal ventilation conditions, the concentration of PM2.5 in the air breathed is 10.97±9.53 mg/m³; however, in poor ventilation conditions, this concentration can rise to nearly three times that amount. These particles not only remain in the kitchen but can also spread to bedrooms and living rooms, creating a broader indoor exposure. The exposure levels in professional kitchens are more continuous. Taking Sichuan cuisine kitchens as an example, health risk assessments show that the carcinogenic risk levels of certain volatile organic compounds reach up to 1.11×10⁻⁴, with a non-carcinogenic risk index of 4.44, where 1,3-butadiene is one of the main contributing substances. At such levels, the cumulative risk cannot be ignored. The impact of cooking fumes begins to cause measurable changes in the respiratory system from short-term exposure. In a kitchen study involving healthy volunteers, lung function tests were conducted on exposure and non-exposure days. The results showed that within six hours after exposure, the forced expiration time increased by 15.7%, while on non-exposure days, it decreased by 3.2%, with the difference being statistically significant. This change suggests a potential transient increase in airway resistance or an inflammatory response. If we further delve into the cellular level, the mechanisms become clearer. In vitro cell experiments have shown that benzo[a]pyrene and 2,4-decadienal in cooking fumes can induce an increased expression of apoptosis inhibitor proteins in lung cancer cells, promoting cell survival and proliferation while also reducing caspase-3 expression, thereby weakening the ability of the cells to undergo apoptosis. These molecular changes provide a biological basis for the risks observed in epidemiological studies. In addition, individual differences can also influence the level of risk. A meta-analysis conducted on Asian populations showed that individuals carrying the GSTT1 deletion genotype had about a 49% increased risk of lung cancer; in areas exposed to coal smoke, those with the GSTM1 deletion genotype had an approximately 64% increased risk. This indicates that genetic polymorphisms may affect the body's ability to metabolize and detoxify the carcinogens found in cooking fumes, making certain groups more sensitive to equivalent exposures. To minimize the harm caused by oil smoke, you can try doing it this way. In conclusion, cooking itself is not the source of disease, but long-term exposure to high-temperature oil fumes can indeed increase the risk of lung cancer. What truly determines risk is the duration and dosage of exposure, rather than a couple of cooking incidents. Therefore, we neither need to panic excessively nor completely ignore the risks; instead, we should maintain rational protection in our daily cooking practices. Specific ways to ensure protection can be found in the following methods: 1. Reduce frying and stir-frying cooking methods. First of all, the cooking method significantly affects the generation of harmful substances. Studies have shown that during the process of pan-frying beef steak, the levels of mutagenic aldehydes and particulate matter produced by margarine are significantly higher than those from canola oil, olive oil, and soybean oil. At the same time, high temperatures and prolonged frying are more likely to produce higher concentrations of aldehydes and PAHs. Therefore, reducing deep frying and repeated high-temperature stir-frying, and preventing the oil temperature from rising to a clearly smoking point, are key steps in lowering the production levels. 2. Turn on the range hood for ventilation before and after cooking. Secondly, ventilation conditions directly determine the inhalation dose. The aforementioned case-control studies have shown that long-term use of range hoods can reduce the risk of lung cancer by approximately half. In everyday life, turning on the range hood and ensuring its ventilation efficiency, as well as continuing to ventilate for a few minutes after cooking, can help reduce the concentration of residual particulate matter. Additionally, regularly cleaning the range hood maintains smooth air exhaust. It is also very important. In addition, for professional chefs, maintaining an efficient ventilation system and conducting regular occupational health monitoring are equally important. In a home environment, selecting the right cooking oil, controlling the oil temperature, and ensuring proper air circulation in the kitchen are practical measures.