From the Journals

Young adults with hypertension may be at higher CVD risk

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Studies raise key questions on hypertension in adults under 40

These two studies suggest that a higher blood pressure level in young adulthood is associated with a greater hazard of premature cardiovascular disease, according to Ramachandran S. Vasan, MD.

However, observing an elevated risk of premature cardiovascular disease does necessarily prove causality, or establish that intervening to lower blood pressure in this age group would lessen that risk, he said in an editorial.

The studies are notable for showing that half to nearly 60% of younger adults had levels of blood pressure considered not normal, he added in the editorial, which appears in JAMA.

It is not clear why so many young adults would manifest higher blood pressure levels in these studies, he said, noting that the umbrella of young adults with hypertension likely includes patients with a variety of subtypes. Those including white-coat hypertension, peripheral amplification with normal central blood pressure, hyperadrenergic state, isolated systolic hypertension, and a smaller subset with secondary hypertension.

“These distinct pathophenotypes may have varying natural histories and their management approaches may be distinctive, suggesting the importance and potential role of subphenotyping of elevated blood pressure in young adults to facilitate treatment decisions,” he wrote in his editorial.

The two studies raise key questions, such as whether there are modifiable social, behavioral, or cultural factors that could prevent elevated blood pressure in younger people, he said.

To date, a substantial body of evidence does suggest that blood pressure levels evolve over the course of life, driven by environmental factors superimposed on genetic risks, and modified by sex and race.

“Overall, these data emphasize that primary prevention of higher blood pressure levels must begin in childhood,” he said.

Ramachandran S. Vasan, MD, is with the section of preventive medicine and epidemiology at Boston University. He reported no conflict of interest disclosures related to his editorial, which was supported by the National Heart, Lung, and Blood Institute’s Framingham Heart Study and a grant from the National Institutes of Health. JAMA. 2018;320(17):1760-3. doi:10.1001/jama.2018.16068.


 

FROM JAMA

Young adults with elevated blood pressure or hypertension, as it is defined in recent U.S. guidelines, may be at increased risk of cardiovascular disease, a pair of recent studies published in JAMA suggest.

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In one study, investigators applied the 2017 American College of Cardiology/American Heart Association blood pressure criteria to nearly 5,000 U.S. young adults followed for approximately 20 years and who had up to a 3.5-fold risk associated with hypertension versus normal blood pressure.

The second study of almost 2.5 million Korean young adults, followed for 10 years, similarly found increased risks of cardiovascular disease later in life for those who had stage 1 or 2 hypertension between the ages of 20 and 39 years.

“These findings from a second country on the opposite side of the globe are consistent with those of the U.S. study, providing further support for the ACC/AHA guideline definitions of hypertension,” Naomi D.L. Fisher, MD, deputy editor, JAMA, and Gregory Curfman, MD, Brigham and Women’s Hospital, Boston, said in an editorial also appearing in JAMA.

Disagreement over the ACC/AHA Guideline for the Prevention, Detection, Evaluation, and Management of High Blood Pressure in Adults threatens to distract from their potential benefits, Dr. Fisher and Dr. Curfman wrote in that editorial.

By redefining stage 1 hypertension as 130/80 mm Hg or higher, down from 140/90 mm Hg or higher, the 2017 ACC/AHA increased the prevalence of hypertension in the United States from 31.9% to 45.6%, they noted.

“Given the magnitude and reach of the global problem of hypertension, it is imperative that dedicated control efforts at the population level intensify,” they said.

U.S. study

The U.S. study, described in JAMA by Yuichiro Yano, MD, PhD, department of community and family medicine, Duke University, Durham, N.C., and his colleagues, was based on analysis of a prospective cohort study, CARDIA (Coronary Artery Risk Development in Young Adults Study), which started in 1985 and enrolled 5,115 black and white adults aged 18-30 years.

They applied the ACC/AHA blood pressure criteria based on each participants’ highest measurement before the age of 40 years, and correlated that with incident cardiovascular disease events that occurred over a median follow-up of 18.8 years.

Patients with normal blood pressure had a cardiovascular disease incidence rate of 1.37/1,000 person-years, compared with 2.74/1,000 person-years for those with elevated blood pressure, 3.15 for stage 1 hypertension, and 8.04 for stage 2 hypertension, investigators found.

That translated into increased risks of cardiovascular disease for those with elevated blood pressure versus those with normal blood pressure. After multivariable adjustment, the hazard ratio for cardiovascular disease was 1.67 (95% confidence interval, 1.01-2.77) for elevated blood pressure, 1.75 (95% CI, 1.22-2.53) for stage 1 hypertension, and 3.49 (95% CI, 2.42-5.05) for stage 2, Dr. Yano and his colleagues reported.

“The ACC/AHA blood pressure classification system may help identify young adults at higher risk for CVD events,” they concluded.

South Korean study

Similar findings were shown in a population-based cohort study, also published in JAMA, that included 2,488,101 adults aged 20-39 years in Korean National Health Insurance Service records.

The investigators looked at mean blood pressure levels from an initial health examination that took place during 2002-2003 and a second examination during 2004-2005.

Follow-up was shorter than the U.S. study, with a median duration of 10 years, reported Joung Sik Son, MD, department of family medicine and biomedical sciences, Seoul (South Korea) National University, and coauthors.

Even so, investigators detected an elevated risk of cardiovascular events for individuals with stage 1 or 2 hypertension versus those with normal blood pressure.

For men with baseline stage 1 hypertension based on the mean values and using the latest ACC/AHA blood pressure criteria, the incidence of cardiovascular disease was 215/100,000 person-years, versus 164 for those with normal blood pressure, with an adjusted hazard ratio of 1.25 (95% CI, 1.21-1.28), the authors said. Likewise, women with stage 1 hypertension had an incidence of 131/100,000 person-years versus 40 for women with normal blood pressure, with a hazard ratio of 1.27 (95% CI, 1.21-1.34).

Men with stage 2 hypertension likewise had a higher cardiovascular disease incidence than did those with normal blood pressure (336 vs. 164 per 100,000 person-years; adjusted HR 1.76), with similar findings seen in women, the report shows.

“Despite the relatively low absolute risk, the difference in absolute risk and the fact that sustained hypertension during longer durations is associated with higher risk of CVD [cardiovascular disease] indicate that early blood pressure management among young adults may lead to significant public health benefits by reducing CVD risk later in life,” Dr. Son and colleagues wrote in a discussion of the results.

Authors of the U.S. study reported disclosures related to Amarin, Amgen, and Novartis outside of the submitted work, as well as grants from the National Heart, Lung, and Blood Institute and National Institutes of Health during the conduct of the study.

Authors of the South Korean study reported no conflict of interest disclosures. That study was supported by the Ministry of Health and Welfare and the Ministry of Education of Korea, along with grants from the National Research Foundation of Korea.

SOURCES: Yano Y et al. JAMA. 2018;302(17):1774-82; Son JS et al. JAMA. 2018;302(17):1783-92.

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