The deaths of children worldwide by flu-related respiratory illness has been calculated for the first time ever, say researchers, and the results are frightening.

In 2008, between 28,000 and 112,000 kids under the age of 5 died of flu-related ailments, almost all of them in developing countries, a new study finds. An accurate number is difficult to determine, researchers say, due to a lack of record keeping and lack of access to health care in some areas, and the difficulty in properly identifying the death as flu-related.

The results were based on a worldwide total of 90 million cases of the flu in 2008 and 20 million cases of flu-related respiratory infections -- such as pneumonia and bronchiolitis -- in children under 5.

Flu complications are often fatal among the elderly -- but it also has a severe impact on young children, says head researcher Dr. Harish Nair of the University of Edinburgh. The study was funded by the World Health Organization and the Bill and Melinda Gates Foundation.