Updated

Women who live the healthiest lifestyles have a 54% lower risk of stroke than women who do not, according to newly examined Swedish data.

That’s a very large reduction in risk, said lead author Susanna C. Larsson of the Institute of Environmental Medicine at Karolinska Institutet in Stockholm.

“We were surprised about the quite substantial reduction in stroke risk among women who adhered to all five low-risk behaviors,” Larsson told Reuters Health by email.

In the study, a healthy lifestyle included five factors: keeping to a heart-healthy diet, having between three and nine alcoholic drinks per week, never smoking cigarettes, keeping moderately active for at least 40 minutes per day and maintaining a body mass index (BMI) below 25.

Larsson and her colleagues used data from an existing study of nearly 32,000 women over age 50 who filled out diet and activity questionnaires in 1997.

Ten years later, there had been 1,554 strokes, including 1,155 cerebral infarctions.

Eating a healthy diet, never smoking and reporting a healthy BMI were all individually associated with a decreased risk of stroke.

The women’s diets were scored based on known benefits of certain foods (fresh vegetables, legumes and nuts, whole grains, low-fat dairy and oily fish). The more of these foods a woman had in her diet, the better her healthy-diet score.

There was also an unhealthy-diet score based on how many servings of foods like sugar, red meat, processed meat, full-fat dairy, white breads and pasta, and fried potatoes in all forms that a woman consumed each week.

Women who never smoked were 17% less likely to have an ischemic stroke than those who had smoked, and those who were physically active were 9% less likely than those who were not physically active to have the same.

Stroke, other cardiovascular diseases and type 2 diabetes seem to be more dependent on lifestyle factors than other conditions like cancer, Larsson said.

Compared to women with none of the healthy lifestyle factors, those with all five had a 62% lower risk of cerebral infarction and a 54% lower risk of any type of stroke.

More than 80% of strokes are ischemic, according to the U.S. Centers for Disease Control and Prevention. Hemorrhagic strokes, in which an artery in the brain ruptures, are less common.

But for hemorrhagic strokes, having a BMI under 25 actually increased women’s risk, according to the results published October 8 in Neurology.

“It’s surprising that the lower BMI group has a higher risk for hemorrhagic stroke,” said Dr. Tobias Kurth, director of research at the Inserm Research Center for Epidemiology and Biostatistics at the University of Bordeaux in France.

“This may be pointing out that one can also overdo it with a healthy lifestyle,” Kurth, who was not involved in the new study, told Reuters Health.

For ischemic stroke, even one healthy lifestyle factor seemed to make a big difference, he said.

“Even if you add one or two, it could really make a difference for these women and this is an important public health message,” he said.

A healthy lifestyle would likely reduce the risk of stroke for men in a similar way, Larsson said.

People don’t need to fit in every category of a healthy lifestyle, she said.

Women who adhered to two of the five lifestyle factors had, on average, a 24% reduction in stroke risk.

“Adhering to one or two lifestyle factors is better than adhering to none,” she said.