People recently diagnosed with lung cancer are at higher risk of having a stroke than those without lung tumors, suggests a large new study from Taiwan.

Researchers looking at data covering more than 150,000 adults found that among those with lung cancer, 26 in every 1000 experienced a stroke each year, compared with 17 in 1000 who did not have cancer. In a Population based Cohort Study Lung Cancer and Incidence of Strokeresearchers found that Lung cancer is associated with increased risk of subsequent stroke within 1 year after diagnosis for men and 2 years after diagnosis for women.The Taiwanese researchers reported in the journal Stroke, that stroke risk was highest during the first three months after lung cancer diagnosis for men and during the first four-to-six months for women.

They also found that a less common type of stroke -- hemorrhagic stroke, caused by sudden bleeding into the brain -- occurred more often among the lung cancer patients than ischemic stroke, which is usually caused by a clot blocking blood flow to brain tissue.

Some evidence suggests that excessive bleeding and blood clots, both of which can be caused by tumors, as well as chemotherapy side effects, could partly explain the apparent link between cancer and stroke, researchers note.

The study used population-based claims data from the Taiwan National Health Insurance, which identified 52 089 patients with an initial diagnosis of lung cancer between 1999 and 2007, and 104 178 matched noncancer subjects from all insured subjects age 20 years and older.Most of the study population were blue-collar workers such as farmers, fishermen and vendors, who tended to have high blood pressure, diabetes and heart disease.

"There's a higher rate of high blood pressure and diabetes and pulmonary disease in patients with lung cancer," said Russman. "I think this reflects the heavy burden of smoking and smoking related risk factors in the population," he said.

According to the American Lung Association, smoking is directly responsible for approximately 90 percent of lung cancer deaths.

"In the U.S., smokers have twice the risk of having a stroke, regardless of lung cancer," said Russman.

Stroke accounted for one out of eighteen deaths in the U.S. in 2007, based on a report by the American Heart Association.

SOURCE: http://stroke.ahajournals.org/content/early/2011/09/08/STROKEAHA.111.615534

 Stroke, September 13, 2011.