"Drug abuse is a huge problem here and it definitely is a cause of hemorrhagic stroke," said Kazuma Nakagawa, M.D., lead investigator and assistant professor of medicine at the University of Hawaii. "But Native Hawaiians and Pacific Islanders are experiencing this form of stroke at a younger age even without methamphetamine use. It's not all about methamphetamines, but possibly due to poor vascular health."

Intracerebral hemorrhage (ICH) is the most common type of hemorrhagic stroke. It occurs when a weakened blood vessel inside the brain ruptures and leaks blood into surrounding brain tissue.

In a retrospective study of ICH patients treated at an Oahu hospital, Native Hawaiians and Pacific Islanders (NHPI) had five times the risk of ICH stroke before age 45 when compared to non-Hispanic white controls. Of the 384 ICH patients studied in 2006-10, 19 percent were Native Hawaiian/Pacific Islanders, 65 percent were Asians and 16 percent non-Hispanic whites.

Researchers found:

• NHPIs were an average 54 years when they had a hemorrhagic stroke compared to 68 years for non-Hispanic whites.
• NHPIs had twice the amount of diabetes (36 percent versus 19 percent) and more than twice the number with untreated high blood pressure (32 percent versus 15 percent) when compared to non-Hispanic whites.
• Intracerebral hemorrhage before age 45 occurred in 26 percent of NHPIs, 9 percent in Asians and only 6 percent in whites.
• Ten percent of NHPI patients tested positive on toxicology screens for methamphetamine use compared to 3 percent of whites and 6 percent of Asians.
• Seventeen percent of ICH before age 45 resulted from methamphetamine abuse.

"Forty-one percent of patients experiencing intracerebral hemorrhage before the age of 45 years were Native Hawaiians and Pacific Islanders," Nakagawa said. "After age 45, only 16 percent were Native Hawaiians and Pacific Islanders."

Besides genetics, environmental factors -- such as diet, stress, unhealthy lifestyles and a lack of good health care -- could also affect the higher incidences, he said. "These groups need a different intensity of treatment in the community. There needs to be a focus on controlling hypertension, diabetes and weight management."

The retrospective study was based on chart reviews in one institution. So researchers are conducting a prospective study to determine the causes of the strokes in young Native Hawaiians and Pacific Islanders.

Cerebral hemorrhage accounts for about 10 percent of 795,000 annual strokes in the United States. This form of stroke is often more severe and disabling than ischemic stroke, which is due to blockage in an artery.

Co-authors are: Megan Vento, B.S.; Matthew A. Koenig, M.D.; Susan M. Asai, R.N.; Cherylee W. Chang, M.D.; and Todd B. Seto, M.D., M.P.H. Author disclosures are on the abstract.

The American Heart Association funded the study.