As more and more Americans have turned to hot tubs for some rest and relaxation, the number of hot tub-related injuries has grown as well, a national study shows.

Between 1990 and 2007, researchers found, emergency-room visits for injuries sustained in a hot tub, whirlpool or spa climbed 160 percent nationwide - from just over 2,500 per year to more than 6,600 in the last study year.

And while people older than 16 accounted for the majority of such injuries, children were also at risk - with near-drownings being the most common danger to children younger than age 6.

The findings, reported in the American Journal of Preventive Medicine, illustrate the potential risks of a dip in a hot tub, as well as the importance of keeping children away from them.

While the majority of injuries occurred among people older than 16, “children are still at high risk for hot tub-related injuries,” senior researcher Dr. Lara McKenzie, of Nationwide Children’s Hospital in Columbus, Ohio, said in a written statement.

“Due to the differing mechanisms of injury and the potential severity of these injuries,” she added, “the pediatric population deserves special attention.”

In general, experts recommend that children, along with pregnant women and people with certain medical conditions - such as heart disease and high blood pressure - avoid hot tubs.

The findings are based on data reported to the U.S. Consumer Product Safety Commission by hospital emergency departments. The researchers considered all injuries that were reportedly linked to a hot tub, whirlpool or spa as being hot tub-related.

From 1990 to 2007, the study found, an estimated 89,597 people were treated for such an injury, with the rate growing over time. Overall, half of the injuries involved slips and falls, while 15 percent involved “hits and scrapes.” About 11 percent were due to heat overexposure.

Almost 3 percent of injuries were near-drownings, with children younger than 6 accounting for two-thirds. A similar percentage of injuries occurred when a hot tub user jumped or dived in; children between the ages of 6 and 12 accounted for 42 percent of those injuries.

To prevent injuries in children, McKenzie and her colleagues advise parents to keep hot tubs covered and locked when not in use, and to consider fencing off the area around the tub.

To prevent falls, they say, consumers should use slip-resistant mats in and around the hot tub; to lower the risk of burns, they should set the water temperature no higher than 104 degrees Fahrenheit and spend no more than 10 to 15 minutes in the water.

Parents should also be sure their tub has covers over the suction drains that meet current standards, according to the researchers. Tub users, especially young children, can be seriously injured or killed if their hair or bodies become trapped by the powerful drain suction.

During the study period, 0.8 percent of hot tub injuries were related to suction-drain accidents.

SOURCE: American Journal of Preventive Medicine, online November 3, 2009.