Many cardiovascular risk factors like high blood pressure and smoking could be linked to the fast decline of memory, attention, learning, and reasoning in seniors, according to a new study published in Age and Ageing.

A team of researchers from King’s College London have discovered that participants over the age of 50 who smoked, experienced higher blood pressure, or were at critical risk for a stroke, did worse on a series of cognitive tasks made to test memory recall, attention, verbal fluency, and several other cognitive results.

Previous research has suggested that as we age, our brain becomes less able to communicate with itself, resulting in declining brain function. This is normal even without conditions such as Alzheimer’s and differs within each individual. In another study published earlier this month, the University of California (UC) Davis found that high blood pressure ages the brain.

This study is one of a small number of longitudinal analyses to examine the simultaneous effect of multiple risk factors on cognitive reduction in elders. Investigators say their results suggest that future clinical trails exploring cognitive decline should center on the combination of these risk factors instead of each factor separately.

Using data from the English Longitudinal Study of Aging (ELSA), a nation wide sample of over 8,000 adults, the authors examined information on blood pressure, smoking, cholesterol levels and body mass index (BMI). They also looked at Framingham cardiovascular and stroke risk scores, which are used to measure the likelihood of a person developing heart disease or stroke within the next 10 years.

Volunteers were followed up with after four and eight years, at each interval undergoing two exams of cognitive performance: memory and executive functioning, later combined into a third category called an overall cognitive index score.

The memory activity consisted of learning ten unconnected words before instant and delayed recall was measured. For the examination of executive functioning, volunteers were asked to name the most animals possible in one minute, measuring their verbal fluency, and to cross-through certain letters in a sequence, examining mental speed, visual scanning, and attention.

The study revealed that smoking had the most significant impact, connected with lower cognitive performance in all of the cognitive tasks after four years. Those with elevated BMI, blood pressure and stroke risks scores did poorly on cognitive activities, however this differs among the three tests.

Elevated BMI was linked with lower results on the memory task, high blood pressure was associated with lower scores for overall cognitive performance and memory, and those with an elevated risk of stroke were found to perform badly across all three examinations.

Dr Alex Dregan, Lecturer in Translational Epidemiology and Public Health at King’s College London, said:

“Cognitive decline becomes more common with ageing and for an increasing number of people interferes with daily functioning and wellbeing. Some older people can become forgetful, have trouble remembering common words or have problems organizing daily tasks more than others. We have identified a number of risk factors which could be associated with accelerated cognitive decline, all of which, could be modifiable. This offers valuable knowledge for future prevention and treatment interventions.”

This study was one of a small number to examine cognitive decline over a long period of time in seniors, which is imperative in recognizing the short and long-term outcomes of cardiovascular risk factors. After eight years, high blood pressure was associated with lower scores on memory tasks and tests of overall cognitive capability, suggesting that high blood pressure has a slow moving impact over a longer period of time.

On the other hand, for those with high stroke and cardiovascular risk, the effect was more immediate (lower scores documented during the four year follow-up). The authors think this may be one reason why short-term trials have unsuccessfully shown the effects of antihypertensive drugs on cognitive decline, as possible advantages may only come about over the very long term.

Future clinical trails based on this study can be targeted at identifying interventions for the UK’s growing population of seniors.

Dr. Dregan concluded:

“Our research suggests that the most promising approach to delaying or preventing early aging of the brain is one that acknowledges the multi-causality of cognitive decline. Thus, current efforts to reduce cardiovascular risk may prove beneficial for cognitive decline. One such initiative is the NHS Health Check program, aimed at preventing cardiovascular disease by inviting 40-74 years olds to five-yearly check-ups in order to assess their risk of developing stroke, diabetes, kidney disease or heart disease, and to offer advice and support to help them manage that risk.”

Written by Kelly Fitzgerald