Blood Pressure (Warren, 2019) – Is high blood pressure genetic?

blood pressure

Nebula Genomics DNA Report for High Blood Pressure

Is high blood pressure genetic? We created a DNA report based on a study that attempted to answer this question. Below you can see a SAMPLE DNA report. To get your personalized DNA report, purchase our Whole Genome Sequencing!

Nebula Genomics sample report on high blood pressure
Nebula Genomics report on variants associated with high blood pressure
To learn more about how Nebula Genomics reports genetic variants in the table above, check out the Nebula Research Library Tutorial.

Introduction (Part 1 of Is blood pressure genetic?)

High blood pressure, also called hypertension, is a clinical condition in which the blood pressure of the arterial vascular system is chronically elevated. Eventually, the force of the blood against artery walls causes additional damage. When measuring blood pressure, the top number is defined as systolic blood pressure and measures the pressure in your arteries when your heart beats. The bottom number is diastolic pressure, which measures the pressure in your arteries in between beats. 

According to the Centers for Disease Control and Prevention (CDC) revised guidelines, high hypertension is a blood pressure at or above 130/80 mm Hg. Stage 2 hypertension is defined when it is at or above 140/90 mm Hg. This definition does not include temporary increases due to illness, medication, pregnancy or during physical exertion. 

What it looks like in the heart and vessels
High blood pressure can lead to atherosclerosis and congestive heart failure. Wikipedia. CC-Attribution 3.0 Unported.

Is high blood pressure genetic?

High blood pressure runs in families. For example, if the parents already suffer from the condition, there is a higher genetic risk being affected by the disorder themselves. The disorder is most likely a combination of many genetic variants. 

More than 100 genetic variations have been associated with primary hypertension. While these variations have been found more commonly in people with essential hypertension than in unaffected individuals, none are common causes of the condition.

The most-studied genetic association in essential hypertension is with genes involved in the renin-angiotensin-aldosterone system. This system produces hormones to regulate blood pressure and the balance of fluids and salts in the body. These genes play an important role in normal blood pressure control.

AGT: This gene controls the production of the protein, angiotensin. Angiotensin is eventually converted to a form called angiotensin II that serves to narrow blood vessels. This molecule also stimulates production of the hormone aldosterone, which triggers absorption of salt and water by the kidneys. The increased amount of fluid in the body also increases blood pressure.

AGTR1: This gene controls the production of the angiotensin II receptor type 1 (AT1 receptor). Angiotensin II binds to the AT1 receptor to stimulate chemical signaling. This signal controls the narrowing of blood vessels and stimulation of the hormone aldosterone. 

Other genes associated with essential hypertension are important for the normal function of the lining of blood vessels (the vascular endothelium). Changes in these genes are thought to impair this cell layer. Such changes may result in vessels that are abnormally constricted or narrowed, which raises blood pressure. 

Researchers suspect epigenetic changes to the DNA also play a role in development of primary hypertension. Epigenetic changes modify DNA without changing the DNA sequence. They can affect gene activity and the production of proteins, which may influence blood pressure.

Epidemiology (Part 3 of Is blood pressure genetic?)

Nearly half of adults in the United States (108 million, or 45%) have high blood pressure defined as a systolic blood pressure ≥ 130 mm Hg or a diastolic blood pressure ≥ 80 mm Hg or are taking medication for hypertension.

Having this condition puts patients at risk for life threatening diseases, such as heart disease and stroke, which are leading causes of death in the United States. In 2018, nearly half a million deaths in the United States included hypertension as a primary or contributing cause.

A greater percent of men (47%) have high blood pressure than women (43%). The disorder is also more common in non-Hispanic black adults (54%) than in other ethnicities, including non-hispanic whites. 

There also appears to be differing levels of prevalence based on geography, with more cases in the southeastern United States than in other areas of the country.

Causes (Part 4 of Is blood pressure genetic?)

Primary hypertension

This is the most common form. It builds up gradually over time and in most cases there is no underlying cause. However, genetics, physical changes to your body, and environmental risk factors are thought to play a role.

Secondary hypertension

In this case, patients develop the disorder as the result of an underlying condition. It is not as common as primary hypertension. It tends to come on suddenly and the value is often higher than in primary hypertension. Some disorders that are known to contribute to hypertension include:

  • Obstructive sleep apnea
  • Kidney disease or kidney failure
  • Adrenal gland tumors
  • Thyroid problems
  • Certain defects you’re born with (congenital) in blood vessels
  • Certain medications, such as birth control pills, cold remedies, decongestants, over-the-counter pain relievers and some prescription drugs
  • Illegal drugs, such as cocaine and amphetamines

Environmental risk factors

The risk factors for high blood pressure are similar to those for any cardiovascular disease, including heart attack and stroke. You may want to talk to your doctor if you have a number of the following risk factors that affect blood pressure:

  • Age. Risk increases with age.  
  • Race. African Americans tend to have an increased risk at a younger age than other ethnicities
  • Family history
  • Being overweight or obese 
  • Not being physically active
  • Smoking or chewing tobacco
  • Too much salt (sodium) or too little potassium in your diet
  • Too much alcohol
  • Stress
  • Health problems that include certain chronic conditions
A blood pressure cuff
Blood pressure can be measured at a doctor’s office. Wikipedia. CC-Attribution-Share Alike 3.0 Unported.

Symptoms (Part 5 of Is blood pressure genetic?)

Hypertension is often asymptomatic and can go undetected for years. In many cases, it only becomes noticeable through the subsequent damage, which is why it is sometimes also referred to as the “silent killer”.

A typical symptom is a headache occurring in the morning, which can be reduced by raising the head of the bed. Other possible symptoms include dizziness, nausea, nosebleeds (epistaxis), fatigue, and insomnia. If blood pressure is severely elevated, shortness of breath (dyspnea) on exertion, angina pectoris, and visual disturbances may occur. Noticeable changes in the feeling of thirst, in the frequency of urination, in the tendency to sweat, or in the ability to exert oneself may also be signs of the condition. 

Diagnosis (Part 6 of Is blood pressure genetic?)

Because the disorder is often asymptomatic and the symptoms are nonspecific, the only way to know if you have hypertension is usually to get regular readings. Most doctors’ offices take a blood pressure reading at every appointment. 

This test is performed by placing a pressure cuff around the upper arm before being manually or electronically inflating it. An inflated cuff compresses the brachial artery, momentarily stopping blood flow. Next, air in the cuff is slowly released while the person performing the measurement listens with a stethoscope or monitors an electronic readout.

Readings are divided into 5 categories:

Reading systolic / diastolic (mm Hg)Type
120 / 80Normal
120 – 120 / 80Elevated (also called prehypertension)
130 – 139 / 80 – 89Stage 1 hypertension
≥ 140 / ≥ 90Stage 2 hypertension
≥ 180/120Crisis

The American Heart Association recommends that if your blood pressure is normal (less than 120/80 mm Hg), your blood pressure should be screened during regular healthcare visits yearly for anyone 20 years of age or older. If you have a family history of heart disease or other risk factors, your doctor might recommend you get readings more often than regular appointments. 

A chart showing the different stages of blood pressure
When it’s time to see a doctor. Wikipedia. CC-CC0 1.0 Universal Public Domain Dedication.

Treatment (Part 7 of Is blood pressure genetic?)

High blood pressure is usually treated with a combination of lifestyle changes and prescription medications. 

Lifestyle changes

Changes to diet and exercise are typically the first treatment option patients discuss with their doctor. The change includes: 

  • Eating a heart-healthy diet with less salt
  • Getting regular physical activity
  • Maintaining a healthy weight or losing weight if you’re overweight or obese
  • Limiting the amount of alcohol you drink

If changes to diet and exercise are not enough, your doctor may recommend medication to help keep blood pressure down. 

Prescription medications

If medication is needed to manage high blood pressure, doctors often prescribe two or three different ones at the same time. The combination appears to work better than a single treatment alone. Sometimes, it takes time and multiple tries to find a combination that works best for an individual. 

Diuretics: These medications help your kidneys eliminate sodium and water from the body. Unfortunately, a side effect of the drugs is increased urination, which may also eliminate too much of the healthy potassium as well. 

Angiotensin-converting enzyme (ACE) inhibitors: These medications help relax blood vessels by blocking the formation of a natural chemical that narrows blood vessels.

Angiotensin II receptor blockers (ARBs): These medications relax blood vessels by blocking the action, not the formation, of a natural chemical that narrows blood vessels. 

Calcium channel blockers: These medications help relax the muscles of your blood vessels. Some slow your heart rate. Calcium channel blockers may work better for older people and people of African heritage than do ACE inhibitors alone. It’s important not to consume grapefruit while on these drugs as it can raise levels of certain calcium channel blockers to a dangerous level. 

Treatments at home
High blood pressure can be managed with lifestyle changes, at home blood pressure monitoring, and prescription medications. Pixabay.

If a combination of the treatments above aren’t effective, additional medications may be added including alpha blockers, alpha-beta blockers, beta blockers, aldosterone antagonists, renin inhibitors, vasodilators, and central-acting agents. 

A doctor may also recommend that a patient monitors their levels regularly at home. Home blood pressure monitors are widely available and inexpensive, and you don’t need a prescription to buy one. It’s important to note that monitoring your blood pressure at home isn’t a substitute for visits to your health care professional.

To learn more about risk factors, diagnosis, and treatment you should look at the resources provided by the National Heart, Lung, and Blood Institute (a member of the National Institutes of Health, NIH) on their website. 

In October 2020, former United States Surgeon General Jerome M. Adams, M.D., M.P.H issued a call to action on hypertension control, including a document that provides strategies for medical providers on how to address this issue. The resource and video can be found on the website for the U.S. Department of Health and Human Services. 

This report is based off of the results of a genome-wide association study conducted by a large group of international researchers in 2018. The research group published their results in Nature Genetics. If you liked this article, you should check out our other posts in the Nebula Research Library!