Stroke risk may depend on your height as a child

People who were very short as children may have to pay closer attention to their cerebrovascular health. A new study suggests that it is these people who are more at risk of having a stroke in adulthood.

Stroke is an event that occurs when the blood supply to the brain is obstructed or otherwise impaired, so that the brain does not receive enough oxygen for it to function correctly.

There are two main types of stroke. These are ischemic, which is caused by a blood clot or an otherwise blocked artery, or hemorrhagic, which is characterized by blood leaks in the brain.

The Centers for Disease Control and Prevention (CDC) estimate that around 6.5 million adults in the United States have had a stroke. It is the currently fifth most common cause of death nationwide.

Known risk factors for stroke include age, hypertension, heart disease, diabetes, obesity, habitual drinking and smoking, and a family history of stroke or cardiovascular disease.

New research from the Bispebjerg and Frederiksberg Hospital and the University of Copenhagen, both in Denmark, may have uncovered a new and surprising risk factor: an individual's height during childhood.

Senior study author Jennifer L. Baker — who is affiliated with both of the institutions named above — and colleagues worked out that adults who had a shorter-than-average height as children were more likely to experience a stroke as adults.

The researchers' findings have now been published in the journal Stroke.

We should focus on modifiable factors

Baker and team conducted a prospective study in which they analized the relevant data — sourced from the Copenhagen School Health Records Register — of 372,636 children from Denmark. They were all born between 1930 and 1989 and were evaluated once every 3 years — at age 7, 10, and 13.

The researchers found that both boys and girls who were 2–3 inches (roughly 5–7 centimeters) shorter than the average height considered normal for their age were more likely to have a stroke later in life than their peers.

More specifically, both boys and girls were more at risk of ischemic stroke in adulthood, and boys in particular had a heightened risk of hemorrhagic stroke later on.

Baker and colleagues explain that there are many reasons why some children may not reach the average height, as expected.

One cause may be genetic factors, but equally important to a child's development is the mother's diet during the course of her pregnancy, and the child's diet throughout their years of growth.

Other reasons behind stunted growth include infection and being exposed to psychological stress. Fortunately, the researchers point out, most of these factors can be prevented, which could also help to reduce a person's risk of experiencing stroke.

"[I]n addition to being genetically determined," write the study authors, "adult height is a marker of exposures affecting childhood growth [...], of which many are modifiable and all are thought to affect the risk of stroke."

Shared fundamental mechanisms?

Moreover, the researchers saw that in high-income countries, the rates of stroke cases and stroke-related mortality were dwindling where the higher adult height rates were on the rise. This was especially true for female populations.

Baker and colleagues surmise that this may be because physical growth and the development of stroke conditions may be determined by overlapping underlying biological mechanisms.

The researchers clarify that these findings are important less in terms of determining risk factors for stroke, and more in terms of understanding some of the root causes of this adverse health event.

That being the case, they suggested that further research should be dedicated to identifying the exact reasons why childhood height is associated with a heightened risk for stroke in later life.

"Our study suggests that short height in children is a possible marker of stroke risk and suggests these children should pay extra attention to changing or treating modifiable risk factors for stroke throughout life to reduce the chances of having this disease."

Jennifer L. Baker