WASHINGTON (Reuters) - Encouraging people to wash their hands properly can reduce the rate of diarrhea by 30 percent, potentially saving lives, researchers said yesterday.

Their review of 14 different studies showed that in rich and poor countries alike, and in schools, hospitals and elsewhere, hand washing is a simple way to stop infections that cause diarrhea.

"This is a huge benefit. For people in low-income areas this effect is comparable to providing clean water," said Dr. Regina Ejemot of the University of Calabar in Nigeria, who led the study.

"The challenge is to find ways of promoting hand washing, as well as to set up long-term trials that test whether good practice has become part of a person's way of life."

Ejemot and colleagues reviewed the various studies for the Cochrane Collaboration, a journal that specialises in reviewing important scientific and medical studies to get a bigger picture of an issue.

Diarrhea kills around 2.2 million people a year, the World Health Organisation estimates. Most are young children in middle- or low-income countries.

The germs that cause diarrhea are found in the gut — and spread through fecal contamination of the hands and water.

Several studies have shown that encouraging children and adults to wash their hands after using the toilet can help. Ejemot and colleagues looked at a variety of studies.

"Hand washing can reduce diarrhea episodes by about 30 percent," they wrote. "This significant reduction is comparable to the effect of providing clean water in low-income areas."

Some of the studies provided soap, while others involved leaflets or other written materials.

"The challenge is to find effective ways of getting people to wash their hands appropriately," the researchers wrote.