Coronary heart disease is associated with a worse performance in mental processes such as reasoning, vocabulary and verbal fluency, according to a study of 5837 middle-aged Whitehall civil servants. The study also found that the longer ago the heart disease had been diagnosed, the worse was the person's cognitive performance and this effect was particularly marked in men.
The study is published online in Europe's leading cardiology journal, the European Heart Journal today (Wednesday 23 July); the authors say it is important because impaired cognition predicts the onset of dementia and death, while coronary heart disease (CHD) remains the leading cause of death in many western countries such as the UK. "It is important to elucidate the link between these two diseases," said Dr Archana Singh-Manoux, who led the research. "The prevalence of dementia rises with age, doubling every four to five years after the age of 60, so that over a third of people older than 80 are likely to have dementia."
Dr Singh-Manoux, a Senior Research Fellow at University College London (UK) and INSERM (Institut national de la santé et de la recherche médicale, France), continued: "This is the first, large study to examine the association between coronary heart disease and cognition. Until now, research on the link between cardiovascular disease and dementia has focused more on cerebrovascular disease than CHD. However, it is CHD and not cerebrovascular disease that makes up the bulk of cardiovascular disease and is a major health problem in the developed world.
"The major risk factors for CHD are cigarette smoking, diabetes, high cholesterol levels and high blood pressure. All of these are modifiable, and smoking, diet and physical exercise are key targets for prevention. Our results on the link between CHD and cognition underline the importance of these preventive measures by highlighting the impact of these risk factors not only on CHD but also on people's cognitive functioning."
As part of the long-running "Whitehall II" study, which was started in 1985 by Professor Sir Michael Marmot, Dr Singh-Manoux and her colleagues assessed the mental processes of 5837 out of 10308 civil servants working in Whitehall (London, UK), who were aged 61. They measured verbal and mathematical reasoning, vocabulary, verbal fluency, short-term verbal memory and they also measured global cognitive status using a mini-mental-state-examination (MMSE). The researchers assessed CHD events, including non-fatal myocardial infarction and definite angina. The date of the cognitive testing was used to classify the first CHD event as having occurred within the last five years, between five to ten years ago, or over ten years ago.
They found that among both men and women a history of CHD was associated with lower scores for reasoning, vocabulary and their global cognitive status (MMSE), when compared to people who had no CHD history. In women, these effects were also seen for verbal fluency.