A twenty- or thirtysomething adult with blood pressure that’s even a little high is risking damage to the structural integrity of his brain that may be evident by the age of 40, says a new study. The early appearance of hypertension’s toll on the brain suggests that physicians should act sooner and more aggressively to control the upward creep of blood pressure in their younger patients, say the authors of the latest research, published online in the Lancet on Thursday.

Neurologists at UC Davis led a study that looked at 579 third-generation participants of the famous Framingham Heart Study. The participants ranged in age from 19 to 63 years old but clustered heavily around age 40. In addition to measuring systolic blood pressure, the study authors scanned each subject’s brain: They precisely measured volume of gray matter -- the interlocking neurons and axons that make up the brain’s central processing unit -- as well as the integrity of the subjects’ white matter, the thick cables of fat-covered brain tissue that speeds electrical signals among brain regions.

Gray matter volume and white matter integrity both decline with age. But the authors found that with each upward jump in a subject’s systolic blood pressure, these indicators of brain aging became more and more pronounced. At every age, higher blood pressure readings meant gray matter volume shrank and white matter integrity decreased.

This meant that the brain integrity of a 40-year-old with hypertension, for instance, was roughly equivalent to that of a person 7.2 years older whose systolic blood pressure reading was in the normal range. A 40-year-old with prehypertension had a brain that looked more like that of a 43-year-old.

It’s become increasingly well established that a person who develops cardiovascular disease is at greater risk of developing dementia. But the latest Lancet study strongly suggests that blood pressure need not reach the widely recognized danger zone to pose a danger, and that the corrosive effects of elevated blood pressure on the brain appear to set in much earlier than has been widely appreciated.

The findings emphasize “the important of aggressive, early management of hypertension as a preventive strategy against cognitive decline in later life” in addition to its role in reducing heart attacks and strokes, the authors wrote. While “optimal” blood pressure control is rarely sought or achieved in younger patients, they wrote, it ought to be.