Smoking, high blood pressure may shrink your brain

The first study to look specifically at the links between smoking, blood pressure, weight and diabetes in middle age, and the way your brain changes as it ages, makes for troubling reading.

Researchers carried out MRI brain scans on 1,300 people over the age of 50 (average age 54). They asked multiple questions about their health and lifestyle, and the people took tests to check their thinking and decision-making abilities.

Ten years later, the tests and the scans were repeated. People with high blood pressure developed age-related changes in their brain at a faster rate than those with normal blood pressure readings. They also had a more rapid decline in scores on tests looking at their thinking and decision-making abilities.

The researchers found that the brains of people with diabetes in middle age shrank faster than those of people who did not have the condition. Smokers also experienced more changes to their brain than non-smokers, and at a faster rate.

People who were obese were more likely to be in the top quarter of those whose scores on decision-making tests had declined the fastest over the 10-year study. They were also more likely to be in the top quarter of those whose brain volume had decreased the most.

The study was described by the researchers as "exploratory" and there are reasons to be cautious about the results. They measured multiple outcomes—for example, the overall size of the brain, the size of different parts of the brain, and the density of specific types of brain tissue. They also used several tests of decision-making and memory. Some of these tests showed a link to blood pressure, smoking, obesity and diabetes. But the more comparisons and tests you do on one set of data, the more likely you are to get some positive findings due to chance.

Bottom line: We can't say for sure that healthy blood pressure, healthy weight, not smoking and avoiding diabetes will protect your brain from age-related changes. But there are plenty of other health gains from having a healthy lifestyle. Keeping your brain working well into later life may be another to add to the list.

Sources
Midlife vascular risk factor exposure accelerates structural brain aging and cognitive decline [Neurology]

—Anna Sayburn, BMJ Group

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