People who struggle to fall asleep and stay asleep may be at a greater risk of a stroke, according to new research published Wednesday in the journal Neurology.

While the study doesn’t prove that insomnia causes stroke, it should prompt those with sleep issues to seek care, the authors contend.

More than 30,000 participants ages 51 and older—about half male and half female, none of whom had experienced a stroke—were surveyed about the quality of their sleep, then followed for close to a decade. They were asked the following questions, each with points assigned to them:

1. How often do you have trouble falling asleep? (most of the time = 2, sometimes = 1, rarely or never = 0)

2. How often do you have trouble with waking up during the night? (most of the time = 2, sometimes = 1, rarely or never = 0)

3. How often do you have trouble with waking up too early and not being able to fall asleep again? (most of the time = 2, sometimes = 1, rarely or never = 0)

4. How often do you feel really rested when you wake up in the morning? (most of the time = 0, sometimes = 1, rarely or never = 2)

Those who scored between 1 and 4 had a 16% increased risk of stroke when compared to those without sleep issues. Those who scored between 5 and 8 saw a 51% increased risk.

In both cases, the elevated risk was due to sleep troubles alone, with other factors that can increase the chance of stroke—like alcohol use, smoking, and sedentary lifestyle—factored out.

The link between insomnia and stroke was strongest in study participants younger than 50 whose score was between 5 and 8, researchers found.

“Managing insomnia symptoms at a younger age may be an effective strategy for stroke prevention,” Dr. Wendemi Sawadogo of Virginia Commonwealth University, the study’s lead author, said in a news release about the research.

Those with the following conditions were at an even greater increased risk of stroke, according to the authors:

• diabetes

• hypertension

• heart disease

• depression

A study published in April in the same journal found that those who got less than five hours of sleep each night were three times more likely to have a stroke than those who got the recommended seven hours.

Ironically, those who got more than nine hours of sleep a night were at greater stroke risk too—they were twice as likely to suffer the potentially deadly medical event, researchers found.