Forty years ago, the surgeon general convened a group of reporters at the heavily guarded State Department on a Saturday morning and released the contents of the first-ever federal study on the dangers of smoking. He was careful to release the seminal report on a Saturday, to lessen reaction on the stock market, and to announce the conclusions from a secure building as there was fear of sabotage. The conclusions: Smoking causes three illnesses—lung cancer, larynx (voice box) cancer, and chronic bronchitis. That report, the first real case against smoking, became one of the biggest stories of the year. Now, smoking is universally recognized as dangerous and a new report from Surgeon General Richard Carmona, while much more sweeping in its conclusions, is not quite as surprising.

What the surgeon general wanted to know: Based on medical studies to date, what diseases can be clearly linked to cigarette smoking?

What they did: The surgeon general and the Office on Smoking and Health looked at more than 1,600 medical studies from the past 40 years from a range of sources and topics and classified each study by how strong a link it showed between smoking and a disease or adverse health effect. They summarized their information to come up with guidelines about how well current research links different diseases to smoking.

What they found: Smoking causes, or partially causes, dozens of diseases, including 12 different forms of cancer and affects nearly every organ in the body. People who smoke are at higher risk for cardiovascular diseases, respiratory diseases, birth defects, infertility, and weak bones, the study found. Among its major conclusions, the study found that smoking affects the entire body, quitting has both immediate and long-term benefits, and low-tar or "light" cigarettes are just as harmful as the full-strength type.

What it means to you: No one disputes that smoking is bad for your health but rarely does a report come out that shows it is this bad. The silver lining is that studies cited in the surgeon general's report show that immediately after putting out a cigarette, the body begins to fix itself. "Within minutes and hours after smokers inhale their last cigarette, their bodies begin a series of changes that continue for years," Carmona says. "Among these health improvements are a drop in heart rate, improved circulation, and a reduced risk of heart attack, lung cancer, and stroke."

Caveats: There aren't any major limitations to this study. For some diseases, the report found there was not enough evidence to conclude smoking was the cause, and so for breast cancer, colorectal cancer, and other conditions the report recommended more research be done.

Find out more: The Internet is not lacking in websites to help people quit smoking. One site that offers a lot of information and statistics is the Center for Disease Prevention and Control's Tobacco Information and Prevention Source (TIPS). But, if you are interested in learning more, the best thing to do is to read the report for yourself.

Read the article: A summary of the report is available free through the surgeon general's website or through the Centers for Disease Control and Prevention.