Study- Activity can prevent illness

WASHINGTON -- Physical inactivity accounts for about 1.9 million deaths a year worldwide, a United Nations report says.

Lack of exercise is one factor contributing to such illnesses as heart disease and some types of cancer, according to an analysis by the World Health Organization.

The analysis published in the World Health Report looked at inactivity as one issue on a wide-ranging list of preventable problems, including chronic hunger, obesity, tobacco use, unsafe sex and unsafe water.

The report is the first to consider the effects of inactivity on a global scale, said the study's director, Dr. Christopher Murray, executive director of WHO's global program on evidence for health policy.

The figures are rough estimates, which may be revised by further studies, said Murray, who added the quality of the data is spotty.

"Are they farfetched? I would say no," said I-Min Lee of the Harvard School of Public Health, who was not involved in the study. "Are they terribly accurate? I would say no. They are basically good 'guesstimates."'

Globally, inactivity ranks 14th on WHO's list of risk factors for disease and death. Seventeen percent of adults -- defined as people over age 15 -- lead sedentary lives, the report said.

By contrast, childhood and maternal underweight from lack of food is the world's leading preventable risk, accounting for about one in 14 deaths, virtually all in the underdeveloped world.

In the developed world, in which more than one-fifth of the human race lives, tobacco is the leading preventable cause of disease and death, accounting for just over 12 percent of cases. Inactivity is the seventh-highest risk factor, accounting for more than 3 percent of disease and death.

Inactivity is more common in the developed world and in the better-off parts of the developing world. In the United States and Canada, WHO said, 20 percent of people don't get enough physical activity. In some industrially advanced areas of the developing world, it's also a problem -- 23 percent of Latin American adults don't get enough activity for good health, the WHO report said.

What keeps inactivity from being an even larger world problem is endemic poverty. Thirty-eight percent of the world's population live in the most undeveloped nations, where less than one percent of people have the luxury of inactivity.

A summary of the findings was published in the online version of The Lancet journal.