Humidity, including steam from hot water, does not actually help in the treatment of the common childhood respiratory illness croup, according to a new study released Tuesday.

The three-year study examined how 140 children with moderate to severe cases or croup reacted to different levels of humidity, said Dr. Dennis Scolnik, an emergency department doctor at Toronto's Hospital for Sick Children.

"In this particular group of patients, humidity had no positive effect in treating their croup symptoms," Scolnik said.

The news was not a surprise to Stephanie, who spent hours in the steamy bathroom when her 2-year-old son, Kyan, had croup, a viral infection of the airway and voice box that causes children to cough.

"I kind of just turned on everything and sat by the shower," she said. "It did get humid in there, but I didn't think it was doing too much for him."

Using masks, the researchers tried specifically sized water particles, and different humidity levels, in hopes of reaching the childrens' voice boxes with moisture.

"Humidity in any form, however well you've prepared it (and) however exactly you're trying to deliver it to the area that's affected by croup, didn't have an effect," Scolnik said.

Scolnik said the process of treating croup with humidity could help, but it wasn't measured in the study.

"The fact that we calmed the parents (and) the fact that the parents were able to calm the child -- the fact some time elapsed -- all could actually make the croup better," he said.

Stephanie said she agrees that comforting her son, Kyan, is what helped ease his cough.

"Once I got him in my arms, I guess, you know, closer contact, he seemed a lot better," she said.

About 5 percent of young children will get croup at least once. It is usually not a serious condition, although about 1 percent of children do actually end up hospitalized.

The study was published in the Journal of the American Medical Association.