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Elevated blood pressure in early adulthood is associated with a greater risk of death decades later, including overall mortality and mortality from cardiovascular disease (CVD) and coronary heart disease (CHD), according to a new study published this week in the November 29, 2011, issue of the Journal of the American College of Cardiology (JACC). The findings represent the first analysis of high blood pressure in young adults that takes into consideration the impact of hypertension during middle age.
Although elevated blood pressure is a well-established risk factor for developing coronary heart disease and stroke, most of the evidence supporting this association has come from studies done in middle-aged and elderly populations. Seeking to better understand this relationship starting in younger individuals, a British and U.S. research team examined long-term data across an approximately 60-year period, beginning when study participants were initially a mean age of 18.3 years old.
The team used information from the Harvard Alumni Health Study (HAHS), which tracked Harvard students from a physical exam at university entry (a mean age of 18.3 years) between the years of 1916 and 1950 through a mailed health questionnaire at middle-age (a mean age of 45.8 years) in the 1960s to the ascertainment of mortality through death certificates available until the end of 1998.
In the initial standardized physical exam, information on smoking, blood pressure, height and weight were recorded. In the mailed questionnaires, study participants were asked if they had received a physician diagnosis of hypertension. From the death certificates, the researchers determined whether the cause of death was from CVD, CHD, stroke, or another cause.
After conducting statistical analysis on the data—including adjusting for age, body mass index, smoking status and physical activity—the researchers found that an elevated blood pressure at the time of the initial exam was associated with an increased risk of all-cause mortality, CVD mortality, and CHD mortality. Specifically, standard deviation (SD) (13.1 mmHg) increases in systolic blood pressure at the initial evaluation were associated with a significant 5% increase in all-cause mortality, an 8% increase in CVD mortality, and a 14% increase in CHD mortality.
These increased risks remained, albeit slightly attenuated, after adjusting for hypertension in middle age. By comparison, hypertension in middle age was associated with a two-fold increased risk of both CVD and CHD and a 57% increased risk of total mortality. There was no association found between blood pressure at university entry and stroke mortality, a “surprising” finding according to the research team given the strong, established association between blood pressure and stroke. Results for diastolic blood pressure were similar to those for systolic blood pressure across all categories.
While the researchers acknowledged the study’s main limitation—that the study participants represented little diversity in sex, race, social class, and lifestyle—they noted the study’s large sample size and number of outcomes as strengths. They also highlighted that the presence of data from both young adult years and middle age allowed the study to be the first to examine “the potential mediating role” of middle-aged hypertension over the life course.
According to the researchers, the results lend weight to the idea of implementing blood pressure-lowering strategies earlier in life than is generally seen in current treatment practices. “More careful attention should be given by clinicians to young and middle-aged adults with elevations in blood pressure to ensure that all lifestyle, dietary, and possibly pharmacologic options are aggressively considered as appropriate treatment modalities to prevent cardiovascular mortality later in life,” said study coauthor Howard D. Sesso, ScD, Associate Epidemiologist at Brigham and Women’s Hospital in Boston.
In an accompanying editorial, Kirsten Bibbins-Domingo, PhD, MD, MAS, associate professor of Medicine and of Epidemiology and Biostatistics at the University of California, San Francisco, notes that the clinical implications of the study’s inference—that blood pressures matters even during young adulthood—are “potentially profound,” as younger individuals are currently less aware of their hypertension, less likely to be on treatment for it, and less likely to have it under control. She adds that the researchers’ message “poses new challenges” to both researchers and clinicians, to “address the difficult evidence gap” about blood pressure treatment in young adults and to “address the growing need to emphasize and support lifestyle approaches to the prevention and control of hypertension,” respectively.
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The American College of Cardiology is transforming cardiovascular care and improving heart health through continuous quality improvement, patient-centered care, payment innovation and professionalism. The College is a 39,000-member nonprofit medical society comprised of physicians, surgeons, nurses, physician assistants, pharmacists and practice managers, and bestows credentials upon cardiovascular specialists who meet its stringent qualifications. The College is a leader in the formulation of health policy, standards and guidelines, and is a staunch supporter of cardiovascular research. The ACC provides professional education and operates national registries for the measurement and improvement of quality care. More information about the association is available online at www.cardiosource.org/ACC.