Five new cancers and four other serious diseases have been added to the list of health problems caused by tobacco.

In the 2004 report, "The Health Consequences of Smoking," the US Surgeon General announced that smoking has been conclusively linked for the first time to acute myeloid leukemia, and cancers of the cervix, kidney, pancreas, and stomach. Smoking is now also known to cause pneumonia, abdominal aortic aneurysm, cataracts, and a serious form of gum disease called periodontitis.

"We've known for decades that smoking is bad for your health, but this report shows that it's even worse than we knew," said Surgeon General Richard Carmona, MD. "The toxins from cigarette smoke go everywhere the blood flows."

Indeed, smoking harms nearly every organ of the body, the report said, damaging a smoker's overall health even when it doesn't cause a specific illness.

Smoking has been linked to lung cancer and other respiratory diseases since 1964, when the first Surgeon General's report on smoking was released. Since that time, the list of tobacco-related illnesses has expanded to include mouth, throat, bladder, and other cancers, as well as heart disease, the top killer of American men and women.

The new report confirms that smoking kills about 440,000 Americans each year and drains $157 billion in medical costs and lost productivity.

Those staggering figures make the fight against tobacco all the more important, said Health and Human Services Secretary Tommy Thompson.

"We need to cut smoking in this country and around the world," he said. "If we are going to be serious about improving health and preventing disease we must continue to drive down tobacco use, and we must prevent our youth from taking up this dangerous habit."

The report notes that quitting smoking has immediate health benefits.

"Within minutes and hours after smokers inhale that last cigarette, their bodies begin a series of changes that continue for years," Carmona said. Circulation improves and heart rate drops, reducing the risk of heart attack. Quitting can also reduce a smoker's chance of developing cancer.

But the report warned that trading in regular cigarettes for "light" or "low tar" brands won't have any health benefits. Previous studies have determined that smokers who choose these seemingly less harmful brands actually inhale just as many harmful chemicals as smokers of regular cigarettes, because they tend to inhale deeper and hold the smoke in their lungs longer.

The report was released to coincide with World No Tobacco Day on May 31, which focuses this year on the relationship between poverty and tobacco.