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Light Smoking Increases Risk of Heart Attack (dateline January 9, 2003)

The health dangers of long-term smoking have been reported to the public for years. However, fewer studies have examined the potential risk of light smoking. Now, results from a large study of women and men find that smoking just a few cigarettes a day can significantly increase the risk of suffering a heart attack, and the risk remains even if individuals do not inhale the smoke from cigarettes. According to researchers, the study highlights the serious dangers of engaging in light or "social" smoking.

The Copenhagen City Heart Study began in 1976; it followed 6,505 women and 5,644 men until 1998 to determine their risk of heart attack and all causes of death. A heart attack, or myocardial infarction, occurs when a coronary artery is so severely blocked that there is a significant reduction or break in the blood supply, causing damage or death to a portion of the heart muscle. Depending on the extent of the heart muscle damage, the patient may experience significant disability or die as a result of a heart attack.

Using data from the Copenhagen City Heart Study, Dr. Eva Prescott of the Institute of Preventive Medicine in Copenhagen, Denmark and her colleagues studied the effects of light smoking on the risk of suffering a heart attack. During the study’s 22 year follow-up period, 476 women and 872 men suffered heart attacks, and 2,305 women and 2,883 men died.

According to Dr. Prescott and her team, women who smoked 3 to 5 cigarettes per day were 2.14 times more likely to suffer heart attacks and 1.86 times more likely to die from any cause than women who did not smoke at all. The men in the studied faced a similar risk: those who smoked 6 to 9 cigarettes per day were 2.10 times more likely to suffer heart attacks to have a heart attack and 1.76 times more likely to die from any cause than men who did not smoke. The risk of heart attack remained even among those who did not inhale the smoke from cigarettes.

Though many people believe that light or social smoking does not pose a serious risk on long-term health, the researchers say their study proves otherwise. "The study emphasizes the importance of recognizing that even very limited tobacco consumption has detrimental health effects," write Dr. Prescott and her colleagues in the September 1, 2002 issue of the Journal of Epidemiology and Community Health.

Previous research has found that cigarette smokers are twice as likely to experience a heart attack as non-smokers. Smokers also have a two to four time higher risk of sudden cardiac death (within an hour of a heart attack).

Other risk factors for heart attack include:

  • Advancing age
  • Gender (males have a higher risk than females)
  • Family history of heart disease
  • Race (African-Americans tend to have higher blood pressure than Caucasians, increasing their risk of heart disease; Mexican Americans, American Indians, native Hawaiians and some Asian Americans also have higher incidences of heart disease)
  • High blood pressure
  • High cholesterol
  • Obesity
  • Diabetes
  • Lack of physical activity
  • Stress

In addition to increasing the risk of heart attack and other cardiovascular problems (such as stroke), smoking also significantly increases the risk of lung cancer. Lung cancer is the number one cause of cancer-related deaths in the United States. The American Cancer Society estimates that in 2002 there will be 169,400 new cases of lung cancer: 90,200 among men and 79,200 among women. Approximately 85% of lung cancer cases can be attributed to smoking.

Smoking has been linked to a host of other health problems including cancers of the esophagus, kidneys, pancreas, cervix, and bladder.

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