(CNN) People who died as a result of a mysterious outbreak of vaping-related lung injury often used products exclusively containing THC, the main psychoactive substance in cannabis, according to new numbers released Monday by the US Centers for Disease Control and Prevention.
Among 19 such deaths with data available on what substances had been vaped, 63% reported exclusive use of products containing THC, 84% reported any use of these products, 37% reported vaping products containing nicotine, and 16% said they'd only vaped nicotine-containing products.
Those who died tended to be older than the wider group of those affected by the outbreak. Just 2% of cases, but almost a quarter of deaths, happened among people over 65. Of 29 deaths analyzed in the new report, the median age was 45, and 59% were male. The youngest death was 17, and the oldest 75.
In total, there have been 36 vaping-related deaths identified in 24 states and Washington, DC: three each from California, Indiana and Minnesota; two each from Georgia, Illinois, Kansas, Oregon and Tennessee; and one each from Alabama, Connecticut, Delaware, Florida, Massachusetts, Michigan, Mississippi, Missouri, Montana, Nebraska, New Jersey, New York, Pennsylvania, Texas, Utah, Virginia and Washington, DC.
As of October 22, there are 1,604 lung injury cases associated with e-cigarette products in 49 states, the District of Columbia and the US Virgin Islands, according to the CDC. That's an increase from the week before, when there were 1,479 cases of vaping-related lung injuries.
According to the CDC, these patients "are mostly young, white males." The vast majority with available data -- nearly 80% -- have been under 35. Roughly the same percentage have been identified as non-Hispanic white. Seven in 10 are men.
Roughly half of all cases, including two of the deaths, have impacted people under 25 years old.
"It is evident from today's report that these lung injuries are disproportionately affecting young people," CDC Director Dr. Robert R. Redfield said in a statement Monday. "As CDC receives additional data, a more defined picture of those impacted is taking shape. These new insights can help bring us a step closer to identifying the cause or causes of this outbreak."
Previous reports have highlighted the prevalence of THC-containing products among the outbreak. According to the latest numbers, based on 867 patients with available data on what they had vaped, 86% reported using products containing THC, 64% reported using products containing nicotine, 52% said they had used both kinds of products, 34% said they used only THC-containing products, and 11% said they used only nicotine-containing products.
"The data do continue to point towards THC-containing products," Dr. Anne Schuchat, CDC's principal deputy director, told reporters Friday. "But I'd like to stress that we don't know what the risky material or substance is. THC may be a marker for a way that cartridges were prepared or way that the devices are producing harm."
Mitch Zeller, the director of the Center for Tobacco Products at the US Food and Drug Administration, cautioned that these data largely rely on self-reports, which may be unreliable.
"It's the person saying, 'I only used the nicotine-containing products,' " Zeller told reporters Friday, adding that some of these reports may come from teens or people in states where products like THC are illegal.
In addition, the new report says some patients may not have known exactly what was in the substances they vaped, "and methods used to collect substance use data varied across states."
Get CNN Health's weekly newsletter
The CDC is recommending "that you do not use e-cigarette or vaping products that contain THC," as the specific cause or substance implicated in the outbreak is still unknown.