In this feature, we take a look at some of the most interesting and important hypertension research from 2020. We cover a range of topics, including COVID-19, the role of thigh circumference, and the impact of dairy.
According to the World Health Organization (WHO), an estimated 1.13 billion people worldwide have with hypertension (high blood pressure). The WHO also indicate that in 2015, 1 in 5 women and 1 in 4 men had hypertension.
A 2020 review concluded that “[h]ypertension is the leading modifiable risk factor for cardiovascular disease and premature death worldwide,” and that prevalence is growing.
Of course, during 2020, COVID-19 eclipsed all else, so it seems sensible to begin this feature with science that addresses both hypertension and the novel coronavirus.
In May, the American Journal of Hypertension published an editorial addressing the relationships between hypertension, hypertension medication, and COVID-19.
Toward the start of the pandemic, some scientists were concerned that high blood pressure might be a risk factor for COVID-19. Some experts also wondered whether antihypertensive medication might increase the risk of contracting SARS-CoV-2.
Understanding whether hypertension is a risk factor for COVID-19 or for developing severe COVID-19 is challenging. Because both COVID-19 and hypertension are more common in older adults, it is difficult to tease the two apart.
As the authors of the editorial explain, “hypertension is exceedingly frequent in the elderly, and older people appear to be at particular risk of being infected with SARS-CoV-2 virus and of experiencing severe forms and complications of COVID-19.”
More than 7 months on, it is still unclear whether hypertension increases the risk of developing COVID-19 or the risk of poorer outcomes. The Centers for Disease Control and Prevention (CDC) state that “Having other cardiovascular or cerebrovascular diseases, such as hypertension […] might increase your risk of severe illness from COVID-19.”
Some people with hypertension take renin-angiotensin-aldosterone system (RAAS) inhibitors, such as an angiotensin converting enzyme (ACE). These drugs may potentially affect the activity of ACE2 receptors, which are also the point where SARS-CoV-2 enters the cells.
Some scientists wondered whether these drugs might, therefore, influence infection risk. There is some evidence that RAAS inhibitors increase the number of ACE2 receptors. As the authors explain, this “could theoretically increase the binding of SARS-CoV-2 to the lung and its pathophysiological effects, leading to greater lung injury.”
Conversely, some research indicates that RAAS inhibitors might protect the lungs from damage and could, therefore, protect against the lung injuries that occur during COVID-19.
Although the discussion is ongoing, at this stage, there does not appear to be a significant link between antihypertensive medication and COVID-19 risk.
A large study published in June “found no substantial increase in the likelihood of a positive test for Covid-19 or in the risk of severe Covid-19 among patients who tested positive in association with five common classes of antihypertensive medications.”
In August, a sizeable review of the impact of RAAS inhibitors on COVID-19 risk concluded that these drugs might have a slight protective effect. The authors write, “this meta-analysis showed that death [or] critical events may even decrease with the use of [RAAS inhibitors] across pathologies, although the analysis failed statistical significance.”
Although COVID-19 dominated scientific publications, there was still space for unrelated research news. After all, hypertension is a significant concern for society, and understanding how to reduce its impact remains urgent.
To diagnose hypertension in young adults, experts recommend that doctors should take several blood pressure measurements over time and average them out. However, according to one study this year, that might not be the best approach.
The research, which appears in JAMA Cardiology, builds upon earlier studies, which suggest that higher variability in blood pressure readings may have links to a higher risk of cardiovascular disease.
For the study, the scientists assessed the blood pressure readings of 3,394 African American and white participants. Around 10 years into the study, Dr. Yuichiro Yano, Ph.D., an assistant professor in the Department of Family Medicine and Community Health at Duke University in Durham, NC, and colleagues identified the young adults who had shown variations in their systolic blood pressure.
They continued to monitor these participants over the next 20 years to investigate a potential link with cardiovascular disease.
The authors found that for each blood pressure spike of 3.6 millimeters of mercury (mmHg) in young adulthood, the risk of cardiovascular disease was 15% higher in the following 20 years.
“If a [person] comes in with one reading in December and a significantly lower reading in January, the average might be within the range that would appear normal. But is that difference associated with health outcomes in later life? […] That’s the question we sought to answer in this study, and it turns out the answer is yes.”
– Lead author Dr. Yuichiro Yano, Ph.D.
Dr. Yano concludes that, when it comes to blood pressure, “Variability matters.”
A study, which appeared in Endocrine Connections in April, investigated the relationship between thigh size and blood pressure in 9,520 participants.
Earlier research had shown that upper-body obesity has associations with an increased risk of hypertension. Surprisingly, the opposite was true of thigh circumference.
The scientists found that in people with overweight or obesity, larger thigh circumference has associations with a lower prevalence of high blood pressure.
“The most likely cause of this association is that there is more thigh muscle or fat [or both] deposited under the skin which secretes various beneficial substances that help keep blood pressure in a relatively stable range,” explains study author Zhen Yang, Ph.D., from Shanghai Jiao Tong University, in China.
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As the average age of humans on planet earth slowly rises, scientists are paying increasing attention to how disease states vary with age. With this in mind, a study published in Age and Ageing examined associations between mortality and blood pressure in the health records of 415,980 older adults.
Among older people with high blood pressure and moderate to severe frailty, the team found a 16% reduction in mortality risk during the 10-year study.
In their paper, the authors explain that “Hypertension was not associated with increased mortality at ages above 85 or at ages 75–84 with moderate [to] severe frailty, perhaps due to complexities of coexisting morbidities. […] The priority given to aggressive [blood pressure] reduction in frail older people requires further evaluation.”
A study, which appears in the journal BMJ Open Diabetes Research & Care, reached a surprising conclusion this year.
The study, which used data from almost 150,000 people, concluded that a higher intake of dairy, especially whole fat varieties, has associations with a lower risk of high blood pressure and diabetes.
They also found that increased whole fat dairy consumption was associated with lower rates of metabolic syndrome.
“Dairy foods and dairy fat provide high-quality protein and a wide range of essential vitamins and minerals, including calcium, magnesium, potassium, zinc, phosphorus, and vitamins A, B-12, and riboflavin.”
– Co-author Andrew Mente, Ph.D.
Although the study does have certain limitations, the authors conclude, “If our findings are confirmed in sufficiently large and long-term trials, then increasing dairy consumption may represent a feasible and low cost approach to [reducing hypertension] worldwide.”
It is worth noting that there are several tried and tested ways to reduce blood pressure, including exercise, reducing salt intake, and losing weight. If you are concerned about your blood pressure, speak with a doctor.
As 2021 drops her landing gear, let us look toward a better understanding of hypertension and more fascinating findings from the realms of medical science.
Similarly, simply discussing hypertension is important. Globally, awareness of the importance of high blood pressure is still lacking.