Negative emotions and anger, as well as sudden changes in body position in response to a startling event, appear to be factors that can trigger a stroke, according to a new study published in the medical journal Neurology.

“We know a lot about risk factors that make people more likely to have a stroke in their lifetime, such as smoking and high blood pressure, but until now we haven’t had any information on what causes a stroke to occur at a particular time,” lead author Dr. Silvia Koton, from Tel Aviv University in Israel, said in a statement.

The findings are based on a study of 200 stroke patients who were interviewed about potential triggers one to four days after the event. The study focused on a variety of possible triggers, including negative and positive emotions, anger, posture changes, heavy physical exertion, heavy eating, and sudden temperature changes.

At least one trigger was identified in 38 percent of the subjects in the two hours prior to stroke onset, the researchers note.

The presence of at least one of the seven triggers raised the risk of stroke by more than eight-fold.

However, the risks seen with the individual triggers varied greatly, ranging from a four-fold increased risk for positive emotions and heavy eating to a 24-fold increased risk for sudden posture change in response to a startling event.

In addition to sudden posture change, anger and negative emotions were the strongest stroke triggers, each raising the risk by 14-fold.

“The main modifiable risk factors for stroke are high blood pressure, smoking, diabetes, [High cholesterol], and obesity,” Koton noted. “However, this study demonstrates that there are factors that may trigger the premature onset of stroke and this is an important area of potential intervention.”

SOURCE: Neurology, December 14, 2004.