High normal blood pressure becomes less of a risk factor for incident cardiovascular disease (CVD) and coronary heart disease (CHD) with age, according to a new study presented today at the World Congress of Cardiology.
The study, carried out over 9.3 years, evaluated the risk of different blood pressure categories among 6,273 participants aged 30 years old and above. The results showed that the risk of developing incident CVD and CHD was significantly higher in people with high normal blood pressure during middle-age (between 30 and 60 years of age) than for people with the same high normal blood pressure aged 60 years and older. Incident CVD and CHD risk was, however, similarly high in people with diagnosed high blood pressure across all age-groups.
"These results reinforce the fact that high blood pressure is a serious risk for CVD in all age groups," said Dr. F. Hadaegh, Prevention of Metabolic Disorders Research Center, Tehran, Iran. "However, the results also suggest that when looking to manage high normal blood pressure resources should be focused on those individuals that are in middle age."
High blood pressure is defined as a repeatedly elevated systolic pressure of 140 mmHg or higher OR a diastolic pressure of 90 mmHg or higher. This study was carried out over 9.3 years and the study protocol established before new guidelines around high normal blood pressure were adapted. In 2003, the Joint National Committee 7(JNC7) from the United States introduced the concept of prehypertension into guidelines categorizing the individuals with systolic blood pressure between 120-139 mmHg or diastolic blood pressure between 80-89 as prehypertension groups.
Hypertension and CVD
Hypertension (high blood pressure) is one of the major preventable risk factors for premature death from CVD worldwide. High blood pressure contributes to around half of all CVD and the risk of developing CVD doubles for every 10-point increase in diastolic blood pressure.
High blood pressure that is left untreated can greatly increase a person's risk of developing CVD. Treating raised blood pressure has been associated with a 35 per cent reduction in the risk of stroke and at least a 16 per cent reduction in the risk of myocardial infarction.