What factor can increase the risk of lung cancer significantly for individuals exposed to asbestos?

The correct answer highlights the significant influence of smoking on the risk of lung cancer in individuals exposed to asbestos. When asbestos fibers are inhaled, they can cause lung damage, leading to conditions like asbestosis and mesothelioma. However, the presence of tobacco smoke substantially augments the cancer risk in these individuals because smoking itself is a primary carcinogen associated with lung cancer.

The combination of asbestos exposure and smoking creates a synergistic effect, greatly increasing the likelihood of developing lung cancer compared to the risk posed by each factor alone. This is why individuals who smoke and have a history of asbestos exposure are at a much higher risk of developing lung cancer, underlining the importance of tobacco cessation especially for those in high-risk occupations.

Other factors, while relevant to overall health, do not have the same profound interactive impact with asbestos exposure. Thus, focusing on smoking provides a crucial understanding of lung cancer risk related to asbestos.