Researchers who conducted an extensive study have concluded that obesity is an independent risk factor for fatal pulmonary embolism in men as well as women, particularly those under age 40.

A pulmonary embolism is a sudden blockage in a lung artery, usually due to a blood clot that traveled to the lung from the leg. If a clot is large, or if there are many clots, pulmonary embolism can cause death. More than 600,000 people in the United States have a pulmonary embolism each year, and more than 60,000 of them die -- most of them within 30 toi 60 minutes.

Reporting in the American Journal of Medicine, the researchers note that obesity has been thought to be a risk factor for fatal pulmonary embolism since 1972, but because of the high proportion of obesity in the general population, previous studies have not determined whether obesity is an independent risk factor.

But after analyzing over 20 years of patient records compiled by the National Hospital Discharge Survey (NHDS) to further investigate the potential risk of obesity in venous thromboembolism, the researchers concluded that obesity is a risk factor for venous thromboembolic disease in men as well as women, particularly those under age 40.

The NHDS is comprehensive in its scope including data on patients of all races and ages obtained annually from 181,000 to 307,000 sampled patient abstracts from 400 to 494 non-Federal short-stay hospitals in 50 states and the District of Columbia. There were more than 12,000,000 obese patients and almost 700,000,000 non-obese patients in the sampled data.

"Now that we know with certainty that obesity is a risk factor for pulmonary embolism, particularly in men and women under age 40, the presence of obesity may alert physicians to a possibility of the diagnosis," said Dr. Paul D. Stein. "The diagnosis of pulmonary embolism is frequently missed even though PE is the third most common acute cardiovascular disease after myocardial infarction and stroke."

Other sources: American Journal of Medicine