A Kansas resident was the sixth person to die in the United States of a mysterious respiratory illness related to vaping, state officials said on Tuesday, as public health officials scrambled to understand a nationwide health problem.

"It is time to stop vaping," Kansas State Health Officer Dr. Lee Norman Norman said in a statement. "If you or a loved one is vaping, please stop."

U.S. public health officials are investigating 450 cases of vaping-related lung illness across 33 states and one U.S. territory. The nationwide investigation led by the U.S. Centers for Disease Control and Prevention and the U.S. Food and Drug Administration has not linked the illnesses to any specific e-cigarette product.