Having extremely low cholesterol may increase the risk for stroke, a new study suggests.

Researchers found that very low LDL, or “bad” cholesterol, and very low triglycerides are associated with an increased risk for hemorrhagic stroke, the type caused by a ruptured blood vessel in the brain.

For the report, in Neurology, researchers reviewed data on total cholesterol, LDL, HDL (“good” cholesterol) and triglycerides for 27,937 women. During an average follow-up of 19 years, there were 137 hemorrhagic strokes.

They found that women with LDL levels below 70 were more than twice as likely to have a hemorrhagic stroke as those with readings between 100 and 129. Under 100 is generally considered normal.

Women with triglyceride readings below 75 had twice the risk for stroke compared with those with levels above 156. A triglyceride level below 150 is considered healthy.

There was no association of stroke with HDL or total cholesterol. The study controlled for hypertension, smoking, physical activity, body mass index and other factors.

“If you have these low levels, you’re often considered low risk,” said the lead author, Pamela M. Rist, an assistant professor of medicine at Brigham and Women’s Hospital in Boston. “But that doesn’t mean you should ignore the other factors that we know are risks for hemorrhagic stroke — hypertension, smoking and so on.”