First study to quantify link between carcinogen byproduct and lung cancer rates . Researchers tracked levels of byproduct ( NNAL ) using urine samples . Smokers with high levels of NNAL doubled their risk of developing lung cancer . Comment: Bottom Line : Watch Dr. Gupta explain the findings » . This test may one day be used to identify smokers at high risk for lung cancer , but wo n't help against smoking 's other health hazards .
First study to quantify link between carcinogen byproduct and lung cancer rates . Researchers tracked levels of byproduct ( NNAL ) using urine samples . Smokers with high levels of NNAL doubled their risk of developing lung cancer . Comment: Bottom Line : This test may one day be used to identify smokers at high risk for lung cancer , but wo n't help against smoking 's other health hazards .