By: Ed Susman

ORLANDO, FL – Overweight smokers have the greatest risk of a venous thrombotic event, according to a review of data from the Copenhagen City Heart Study reported here.

The risk of venous thrombotic event increases with body mass index and tobacco usage, said Anders Holst, MD, a research fellow in cardiology at University Hospital Rigshospitalet.

“The more you smoke, the greater your risk,” Holst said during a poster presentation at the annual meeting of the American Heart Association.

Holst gleaned the information from records of 18,954 subjects from 1976 through 2007. During that period, 992 venous thrombotic events were recorded. Of those, 732 of those events were primary, with unknown causes, while the rest were secondary events – the result of fractures, prolonged bed rest, cancer, and procedures such as abdominal surgery and knee and hip replacements.

Using never-smokers as the reference point, Holst observed that former smokers had an insignificant 2% increase in the risk of deep vein thromboses or pulmonary embolism.

Smokers who consumed 1 to 14 grams of tobacco (up to 17 cigarettes) a day had a 31% increased risk of an event (P=0.006), while and smokers of 15 to 24 grams of tobacco (18 to 30 cigarettes) increased their risk of an event by 47% (P<0.001). Those who smoked more than 25 grams of tobacco a day had a 60% increased risk (P=0.001).

Weight was also a major factor in risk. A body mass index of less than 20 was the reference point for measurement, but up to a body mass index of 25 there there was no significant difference in risk.

A body mass index of 25 to 30 increased risk by 27%, but not significantly (P=0.15). A body mass index of 30 to 35 significantly increased risk by 67% (P=0.004), while a body mass index over 35 more than doubled the risk venous thrombotic event (P<0.001).

“We did not calculate whether being overweight and smoking increased the individual risk or was synergistic and increased risk greater,” Holst said. “I think that is going to be my next project with this data – to see how having more than one of the risk factors impacts venous thromboses.”

“These findings from Denmark are what we would expect to see as causes of thrombotic events,” said Douglas Weaver, MD, head of cardiology at Henry Ford Hospital, Detroit, Mich.

“Smoking and being obese puts you at risk for lots of bad things, and this is just one more of them,” he told MedPage Today.

Holst’s data also showed that the highest levels of diastolic blood pressure also impart a significant risk of venous thrombotic event, but he said that might be the result of chance. Higher income appeared to offer a protective effect, but similarly, that finding was much weaker than the cigarette and obesity findings.

The risk of venous thrombotic event increases with body mass index and tobacco usage, said Holst.

“Although some of the risk factors are shared,” Holst said, “important risk factors for atherosclerotic disease such as dyslipidemia and systolic blood pressure were not associated with venous thromboembolism.”

- MFP Wire Services
- 11-20-2009