The Odds of Dying

When major catastrophes strike, like the recent Asian earthquake and tsunami, the mass deaths can lead one to think that natural disasters are the most likely way people can die.

Not by a long shot.

According to the National Center for Health Statistics, the leading causes of death in the United States are, in this order, heart disease, cancer, stroke, chronic lower respiratory diseases, and "accidental injury," a broad category that includes a lot of stuff that just happens.

You are more likely to commit suicide or fall to your death than be killed by a tsunami or any natural disaster, the odds say. [See Table]

In less advanced countries, where residents often live in poverty and huddle near the sea or in poorly constructed houses, tsunamis, floods and earthquakes are a more looming threat. But even in such locales, there are far greater risks over the course of a lifetime.

Nature's power

There are no formal estimates on the risk of death by tsunami, because they occur so infrequently.

About 2,200 died in a Papua New Guinea tsunami in 1998; roughly 8,000 in the Philippines in 1976, about 120 in Hawaii and California in 1964. You have to go back to 1896 — 27,000 deaths in Japan — to find one that even approached the 150,000-plus scale of the Asian disaster on Dec. 26, 2004.

Michael Paine, of the Planetary Society Australian Volunteers, monitors and calculates risks of low-frequency events like asteroid impacts and tsunamis. He estimates the odds of a tsunami being the average coastal dweller's cause of death, globally speaking, are around 1-in-50,000. For the average citizen in the United States, given that many don't live near the coast, the chances are 1-in-500,000 or even perhaps less likely. Paine stressed this is a very rough estimate.

The real odds drop to zero, of course, if you live in the mountains and never visit the shore.

In fact, that sort of risk management — intentional or not — goes for many things. Frequent flyers are more likely to die in a plane crash than someone who never flies. A Californian is at greater risk from earthquakes than someone in Minnesota.

Overall, global deaths from sudden natural disasters — things Nature dishes out over moments, hours or days — have been on the decline in recent years, with the exception of 2003 and 2004. Officials credit better warnings and swifter response to help victims.

In 2003, the last year for which worldwide deaths have been tabulated by the Red Cross, natural disasters killed 76,000 people. The figure was skewed by two events: a heat wave in Europe that overcame more than 22,000 and an earthquake in Iran that killed upwards of 30,000. (Earthquakes kill roughly 10,000 people every year, on average.)

The bigger threats

The previous ten years saw an average of 62,000 global deaths per year from natural disasters. That's far less than the tolls taken by famine, disease and war.

Communicable diseases kill millions of people every year (13.3 million 1998, according to the World Health Organization).

In sub-Saharan Africa last year, AIDS killed about two million people, according to a recent article in the Wall Street Journal. Even more died because of bad water or sanitation systems. In Kenya, AIDS deaths are "equivalent to two 747 jets crashing every day," stated a recent Red Cross report.

Another study estimated that 3.3 million people died due to war in the Democratic Republic of the Congo from 1998 to 2002. More than three-quarters of the deaths owed to diseases and malnutrition resulting from the fighting.

Globally, violence is a leading killer. It accounts for 14 percent of all deaths among males and 7 percent among females, according to a 2003 analysis by the World Heath Organization. On an average day, 1,424 people are murdered. Somebody commits suicide every 40 seconds.

Changing risk factors

Perceptions of risk factors can change over time simply because more is learned. The chances of an Earth-impacting asteroid killing you have dropped dramatically, for example, from about 1-in-20,000 in 1994 to something like 1-in-200,000 or 1-in-500,000 today.

The new numbers — their range reflecting the need for further research — were offered up last week by Clark Chapman of the Southwest Research Institute and David Morrison at NASA's Ames Research Center.

Why such a dramatic downgrade? Active intervention.

"A significant part of it is that we have now discovered, in the last dozen years, a good fraction of the largest, most deadly asteroids and found that they won't hit the Earth," Chapman told LiveScience.

Also, projections of the destruction a large space rock would cause have been revised downward a bit. Finally, since Earth is two-thirds water, asteroid risks include the possibility of an impact-induced tsunami. And Chapman says asteroid-generated tsunamis may not be as deadly as once presumed.

Others contend the odds of death-by-asteroid are still about 1-in-50,000, until the remaining handful of expected large asteroids are found and determined not to be a near-term threat.

"This is a matter of hot, ongoing debate and calculations, however, partly motivated by the recent Indian Ocean tsunami," Chapman said.

Which brings up another huge margin of error. The death toll in Asia was greatly increased by the lack of a tsunami warning system, whereas there is one covering the Pacific Ocean.

"Our risk exposure from impact tsunamis depends heavily on the existence of such warning systems," Morrison said.

Both scientists stress that the asteroid risk is just an estimate. Like everything in this article. In the end, the only stat you can really count on is the overwhelming likelihood that you will, in fact, pass on.

By the numbers

There are significant caveats to consider before you contemplate the table below.

Risk varies with age. Infants face different threats than teens, whose risks are wildly different from senior citizens. Among people age one through 44, injuries are by far the leading cause of death in the United States. But heart disease is the hands-down No. 1 killer for those over 65. Since average life expectancy is about 77 years in the United States, simple logic reveals the leading killer of Americans.

The numbers get murkier the closer you look. Statistics are typically given for a person born in the year the numbers are crunched, but by the time that person grows up, the outlook will have changed because of medical advances, diet shifts, changes to the environment, and so on.

The list below is not complete. Rather it includes life-ending scenarios that carry some of the highest odds for U.S. residents, along with the chances of checking out in more bizarre fashion.

Health-related statistics and categories with high-odds (like heart disease at 1-in-5) are among the most statistically significant, sort of. All odds fluctuate from year-to-year. Toss in a flu pandemic — some 50 million died in 1918 — and all bets are off. The World Health Organization recently warned that the next such bout could kill 7 million people "in a best case scenario." That's not in the odds below.

The more specific figures are based on 2001, the most recent year for which complete data are available. Other odds, indicated with an asterisk (*) are based on long-term data.

All figures below are for U.S. residents.

** Perhaps 1-in-500,000

SOURCES: National Center for Health Statistics, CDC; American Cancer Society; National Safety Council; International Federation of Red Cross and Red Crescent Societies; World Health Organization; USGS; Clark Chapman, SwRI; David Morrison, NASA; Michael Paine, Planetary Society Australian Volunteers