April 15 (HealthDay News) -- Prolonged fasting may increase the risk of a rare type of stroke almost three-fold, according to a new study.

The research focused on five years of data from three hospitals in Iran, a Muslim country where fasting is a religious practice followed during the month of Ramadan. During the month, the average number of people admitted for cerebral venous sinus thrombosis (CVST), was 5.5, compared with 2.0 during the rest of the year.

CVST is a rare type of stroke that most often affects young adults and children and is more common in women. However, the study results showed that the average age and percentage of men versus women was the same in the two groups of patients.

The study was to be presented Tuesday at the American Academy of Neurology annual meeting, in Chicago.

"These results need to be confirmed by other studies, but they should be looked at carefully," study author Dr. Mohammad Saadatnia, of Isfahan University of Medical Sciences, said in a prepared statement. "Coexistence of usual risk factors, such as oral contraceptive and coagulopathic disorders, along with dehydration in patients while prolonged fasting can be the reason for increased susceptibility to CVST. People and their physicians need to be aware of possible complications of prolonged fasting."

Previous studies have shown that fasting during Ramadan does not affect the rate of arterial stroke. More than one billion Muslims fast worldwide during Ramadan.

SOURCE: American Academy of Neurology, news release, April 15, 2008