Poor Heart Health and IQ Linked to Early Dementia

Early onset dementia associated with poor cardiovascular fitness and lower cognitive performance at age 18

(RxWiki News) Being physically fit and mentally healthy in your youth may help you grow old with your brain faculties intact.

A recent study found that men who had either poor cardiovascular fitness or a lower IQ when they were young were more likely to develop early-onset dementia.

If men had both of these risk factors, they were even more likely to have dementia at an early age than men who had neither.

Early-onset dementia is defined as dementia before the age of 65.

"Start doing heart-healthy exercises when you're young."

This study, led by researcher Jenny Nyberg, PhD, of the Center for Brain Repair and Rehabilitation at the University of Gothenburg in Sweden, included more than 1 million Swedish men.

The men were enrolled at age 18 when they were drafted into the army and underwent exams to assess their ability to enter service. Enrollment started in 1968 and ended in 2005. The participants took part in exams for cardiac fitness using the cycle ergometer test, which is a stationary bicycle test that can measure how hard an individual is physically working, and cognitive tests that included logical, verbal, visuospacial and technical testing.

The men were followed for an average of 25.7 years.

The researchers then used the Swedish National Hospital Discharge Register to see how many men were diagnosed with early-onset dementia or mild cognitive impairment, which can lead to early-onset dementia. They also looked at the Swedish Cause of Death Register.

The men who fared low on the physical exam were 2.5 times more likely to develop early-onset dementia later in life. The men who were found to have a low IQ had a four-times greater risk for the disease.

Although doing poorly in each of the cognitive tests was slightly predictive, it was a low performance overall that increased risk for later developing both mild cognitive impairment and early-onset dementia.  

Mild cognitive impairment is impairment in mental functioning in people who do not yet have dementia. It is a slight decline in cognitive abilities, including memory and thinking skills. It is thought that mild cognitive impairment may be a precursor to dementia, although the cognitive problems may never worsen, and even, in some cases, they may improve.

There are different types of dementia, but it is considered to be a more severe cognitive problem than mild cognitive impairment and effects memory, thinking. language, judgment and behavior.

In this study, having both poor cognitive functioning and being unfit in cardiac health were linked to a seven-fold increased risk for early-onset dementia compared to those without either deficit.

The researchers controlled for things like parental education, individual education, and BMI (body mass index is a measure of body fat) and still found the associations.

These researchers acknowledged that their study lacked pathological confirmation of diagnoses (they used records to confirm diagnoses) and some patients may never have been admitted to hospital-based health care for their mental issues.

The researchers pointed out that previous research has shown the prevalence of early-onset dementia to be about 55-98 people per 100,000 in the age group 45-64 years. These researchers found a similar rate.

In a press release, Professor Georg Kuhn, senior author of this study, encouraged people to be fit. "Good cardiovascular fitness makes the brain more resistant to damage and disease," he said.

This study appeared online in the March 7 issue of Brain.

Review Date: 
March 11, 2014