Cardiac Risk in Young Adults Associated with Cognitive Changes in Middle Age

A group of researchers based at the University of California, San Francisco (UCSF), have shown that when cardiovascular risk factors (CVRF) such as elevated glucose and high blood pressure begin in early adulthood, they are associated with significantly worse cognitive function in middle age compared with having no CVRF.

The study by researcher Kristine Yaffe, MD, et al, was published online in Circulation on March 31, 2014. Dr. Yaffe is professor of psychiatry and neurology at UCSF, and is supported by BrightFocus.

The team analyzed data from several thousand 18- to 30-year-olds enrolled in the Coronary Artery Risk Development in Young Adults (CARDIA) study. That study began in 1985 and followed subjects for 25 years. Every two to 5 years, they had a medical evaluation and their cardiac risks were assessed. After 25 years, they were assessed for cognitive function using three standardized tests.

The results showed that:

• Those whose blood pressure and glucose levels exceeded recommended levels during the 25-year study displayed performed worse on three standard tests that measure executive function, cognitive processing speed, and verbal memory.
• The association with lower cognitive function was small, but statistically significant, for most of the CVRF.
• High cholesterol was associated only with poor verbal memory.

Why Is This Study Important?

Previous studies have demonstrated there is a strong connection between cardiovascular health and brain health.

However, whereas most previous evidence is linked to events in later life—i.e., the development of Alzheimer’s disease or another form of dementia in old age following cardiovascular risks seen in mid-life ), this study is one of the first to investigate the effects of early life CVRF on cognitive function in midlife (i.e., at age 50 or thereabouts). And even though the effects seen in this middle-aged study population are mild, evidence is strong based on a large sample and cumulative exposure to CVRF over 25 years.

In a press release, Dr. Yaffe was quoted: “We already know that reducing these risk factors in midlife can decrease the risk of dementia in old age. If it turns out that the damage begins before middle age, we may need to work on reducing heart disease risks in earlier stages of life”—i.e., in young adulthood.

Since cognitive function was not measured at the beginning of the study, the investigators were not able to estimate exactly how much cognitive function was lost in the group with CVRF. “We can say that almost for sure they don’t have dementia,” Dr. Yaffe said in an interview with The Washington Post about the study.

However, “the fact that we’re able to see [the association] so early is kind of amazing, and it’s kind of sobering and exciting,” she said.