Health habits during childhood and adolescence may play a crucial role in people's risk of stroke later in life, a new study finds.

People who lived in the region known as the “stroke belt” as children or teens had a higher risk of stroke even if they lived elsewhere during other periods in their lives compared with people who spent their childhoods or teen years elsewhere, according to the researchers. States in the Southeast U.S. comprise the stroke belt.

The findings suggest that “If we are going to prevent strokes in adults, waiting until the underlying risk factors — problems such as hypertension and diabetes — develop may be too late. We need to start in childhood,” said study researcher Virginia Howard, a stroke epidemiologist at the University of Alabama at Birmingham School of Public Health.

The researchers also found that people who grew up outside the stroke belt but moved into it during adulthood had a higher risk of stroke than people living elsewhere, but not as high as those who lived in the stroke belt during childhood and then moved out.

Howard emphasized that while the geographic boundaries of the stroke belt were used in the study, the findings actually apply to people's lifestyle habits no matter where they live. “Being physically active, eating a healthy diet, managing weight, etc.—- all of these kinds of healthy lifestyle factors can reduce the risk of developing these risk factors,” she said.

Living in the stroke belt

In the study, the researchers used a subset data from a large national study focused on finding risk factors for having a stroke. They looked at 25,500 people and considered which periods of their lives, if any, were spent living in the stroke belt. Over the six-year study, 615 people had a stroke.

The researchers found that people who lived in the stroke belt at any age tended to have an increased stroke risk.

They also found that “living there early in life appeared particularly potent with regard to stroke risk,” Howard said.  People who lived in the stroke belt for their first 12 years, or between the ages of 13 to 18, were 22 percent more likely to have a stroke than people who spent these periods of life living elsewhere.   The researchers accounted for factors that could influence people's risk of stroke including their age, race, sex.

Moreover, when the researchers further accounted for even more factors that affect stroke risk, such as having diabetes and smoking, they found that the risk of stroke was increased only in people who lived in the stroke belt as teens.

Why early life is important

While it's not exactly clear why people who lived in the stroke belt during their early years continue to be at greater risk for stroke, “we speculate that it is because childhood and the teenage years are when many lifelong habits and decisions are made,” Howard said.

This period “is when your dietary patterns are first set, when you are deciding whether to smoke cigarettes, when you are deciding whether to be physically active,” she said. Such decisions may set into motion the processes in the body that ultimately increase the risk of having a stroke as an older adult.

The study shows an association, not a cause-and-effect relationship, between living in the stroke belt during early life and later having a stroke, the researchers noted in their study. But stroke belt states tend to have some of the poorest childhood health circumstances, including high rates of low birthweight babies, high infant, child and teen mortality, and high teen birth rates.

It could be that such conditions cause poor childhood health, which, in turn, causes increased stroke risk, or it could be that stroke risk and these poor health circumstances in childhood share common causes, Howard said.

The study is published online today (April 24) in the journal Neurology.

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