Researchers Find New Connections Between Sleep Apnea And Hypertension In African-Americans

A new study may have found more evidence of a connection between sleep apnea and cases of hypertension in African-Americans.

The study was funded by the National Heart, Lung, and Blood Institute. Researchers found that, out of a cohort of African-Americans diagnosed with hypertension, about one-fourth suffered from sleep apnea. This is a sleep disorder where the airway closes during the night and breathing temporarily stops.

The study also showed that subjects with extreme sleep apnea had a higher chance of experiencing resistant hypertension. In other words, their blood pressure remained high even with the use of three anti-hypertension drugs.

We spoke with study author Dr. Dayna Johnson, assistant professor at Emory University’s Rollins School of Public Health. By email, she told Mattress Clarity, “Given the high prevalence of sleep apnea among African-Americans, and the prior work that has shown that sleep apnea can affect hypertension, we hypothesized that sleep apnea may also affect hypertension control among African Americans.”

[Editor’s Note: The content provided on this site is for general informational purposes only. Any information provided is not a substitute for professional medical advice. We encourage you to consult with the appropriate health expert if you have concerns.]

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Our Hearts And Our Sleep

According to a 2007 study, African-Americans are generally more likely to deal with hypertension compared to caucasians (1). In addition, the American Heart Association says that over 40 percent of African-Americans suffer from some form of hypertension. The hypertension is often severe and tends to develop at an earlier age than it does in caucasians.

In this new study, which was published in the journal Circulation, Johnson and her colleagues looked at a cohort of 664 African-Americans with hypertension. This cohort was part of the Jackson Heart Study, a large study of cardiovascular health among African-Americans living in Jackson, Miss.

To collect their data, the researchers gave each of the study’s participants a Type 3 sleep apnea study (a portable sleep monitor that measures airflow and respiration) to take home with them. After observing these overnight readings, the researchers assigned each participant to one of four classifications: They did not have the condition, or they had mild, moderate, or severe sleep apnea. The researchers also measured the subjects’ blood pressure.

Johnson told us that their approach differed from earlier studies regarding the subject. “We investigated this association in a large population of African-Americans using objective sleep testing,” she told Mattress Clarity. “Many of the prior studies did not include a large number of African Americans and used questionnaire-based assessments of sleep apnea, which are not as accurate as testing.”

RELATED: Can CPAP Treatment Improve Sleep Apnea Patients’ Sex Lives?

A man sleeps while wearing a CPAP machine.
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Extreme Sleep Apnea And Resistant Hypertension

Among the study’s participants, close to 25 percent of the subjects showed signs of some level of sleep apnea. Out of this 25 percent, almost 94 percent had not been diagnosed with the sleep disorder.

Additionally, almost 50 percent of subjects were having trouble controlling their blood pressure despite taking one or two anti-hypertension medications. Fourteen percent had resistant hypertension.

Drug-resistant hypertension occurs when you continue to see high blood pressure despite the use of several antihypertensive medications (3) or when it takes four or more medications to control high blood pressure, whereas milder forms are apparent when blood pressure is high with a lower number of medications (1 or 2) required to control it,” Johnson said.

When they compared the sleep apnea classifications and levels of hypertension, Johnson and her team found that subjects with moderate sleep apnea were almost twice as likely to have resistant hypertension compared to those without sleep apnea. Those with severe sleep apnea were over three times more likely to show signs of resistant hypertension.

For Johnson, some of these results were expected, while others were surprising. “Based on the literature, we are not so surprised that sleep apnea was related to resistant hypertension,” she said. “However, it was alarming to see the number of participants with undiagnosed sleep apnea (therefore untreated).”

In Johnson’s opinion, these findings are a call to action for diagnosing and treating sleep apnea in African-Americans. She said, “Our results suggest the need for screening African-Americans for sleep apnea, particularly those that may be at risk and have hypertension.”

[Editor’s Note: The content provided on this site is for general informational purposes only. Any information provided is not a substitute for professional medical advice. We encourage you to consult with the appropriate health expert if you have concerns.]

Featured image: Andrey_Popov/Shutterstock

References

  1. Lindhorst, Jane et al. “Differences in hypertension between blacks and whites: an overview” Cardiovascular journal of Africa, vol. 18,4 (2007): 241-7.
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Marten Carlson

Marten is a staff writer for Mattress Clarity News. He covers the mattress industry as well as sleep science news. He is specifically interested in the connection between sleep and overall health.Marten has written for media publications like Consequence of Sound and received a master’s degree in Film Studies from Emory University.He comes from Franklin, Indiana, and spends all the time he can writing, directing, and acting in films. He has directed genre short films and features. His newest film, Starlets, recently premiered at the River Town Film Festival in Clinton, NJ. He also stars in the upcoming thriller, Sour Bear. His next film, At The Hop, is a hot rod actioner with a horror twist.

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