Heart disease, high blood pressure and diabetes may combine in patients to worsen thinking skills, according to UK researchers.
Patients with hypertension, diabetes or coronary heart disease perform worse on mental tests of reasoning, memory and reaction time, and having more than one of these conditions has an even greater effect, researchers found.
“Having two diseases was worse and three worse still”
The study, published in the European Heart Journal, suggests that preventing or delaying cardiovascular disease or diabetes may delay cognitive decline and possible dementia.
The authors, from the University of Glasgow, noted that a decline in cognitive abilities could be an important precursor to mild cognitive impairment or dementia in older age.
While previous research has made the link between cardiometabolic diseases and worse cognitive abilities, the additive effect on cognitive skills of having more than one of these diseases has not been known until now, they said.
The researchers studied nearly half a million participants from the UK Biobank, using data taken between 2006 and 2010.
“Our work has important implications for future research in this important area”
Participants’ data was divided by medical history and the number of cardiometabolic diseases they had. Scores on tests of reasoning, reaction time and memory were then compared.
Study author Dr Donald Lyall said: “Having one disease was associated with poorer performance on all the cognitive tests; but having two diseases was worse and three worse still, particularly for reaction times and reasoning.
“Importantly our analysis took account of lots of things which might have resulted in an erroneous result; such as medication usage, gender, age, deprivation, education levels, depression, smoking history, alcohol intake, and obesity,” he said.
Dr Lyall said the findings highlighted the “potential to protect” against cognitive decline by addressing other conditions such as heart disease.
“The reduction in mental test scores was relatively small for individuals, but may expand as people age,” he noted.
“Given rising levels of multi-morbidity, i.e. where people are living with more than one chronic disease, and public health concerns regarding cognitive decline, our work has important implications for future research in this important area,” he added.