A 50-year-old Kansas woman died Tuesday of potentially vaping-related severe respiratory disease, becoming the sixth instance in the U.S.

The woman, whose name has been withheld, was said by health officials to have had a history of health issues but her rapid decline prior to her untimely death was most likely caused by her use of e-cigarettes. She suffered from acute respiratory distress syndrome (ARDS), a condition that causes the lungs to fill with liquid.

“She had some underlying medical illnesses,” Dr. Lee Norman, Secretary for the Kansas Department of Health and Environment, told NBC News. “But nothing that would have foretold the fact that within a week after starting using e-cigarettes for the first time, she developed full-blown acute respiratory distress syndrome and died.”

This patient had been one of six under investigation for confirmed or suspected vaping-induced severe lung disease in Kansas. As of Monday, the Center for Disease Control had discovered over 400 cases of lung disease linked to vaping nationwide. Most of these patients are in their 20’s or 30’s, but Norman stressed that this Kansas woman’s case was an indicator that vaping may pose a greater risk to older individuals and those with pre-existing conditions.

“It's a reminder that older people with pre-existing illnesses are probably going to have worse clinical outcomes if they do develop problems with vaping,” Dr. Norman said.

No exact cause of the conditions has been confirmed, but some have suggested they are linked to the use of e-cigarette liquids containing nicotine or cannabis.

Industry leader Juul has recently come under fire for advertising its vaping products as safer alternatives to traditional cigarettes, a claim which it has not proven to the Food and Drug Administration.

e-cigarette vape
An e-cigarette is use at the Vaping Buddha in South San Francisco GETTY IMAGES NORTH AMERICA / Justin SULLIVAN