3 in 4 Black Americans Develop Hypertension By Age 55

The vast majority of African Americans develop high blood pressure by their mid-50s, compared to just over half of white men and less than half of white women, a newly published study suggest.

Data from the ongoing, prospective Coronary Artery Risk Development in Young Adults (CARDIA) study indicated that blacks had a 1.5- to 2-fold higher risk for hypertension compared to whites after multivariable adjustment, regardless of their blood pressure levels in young adulthood, according to S. Justin Thomas, PhD, of the University of Alabama at Birmingham, and colleagues.

Their study, published online in the Journal of the American Heart Association. involved 3,890 CARDIA participants with normal blood pressure at enrollment at ages of 18 to 30. High blood pressure was defined under revised 2017 American Heart Association/American College of Cardiology guidelines as 130 mm Hg or higher diastolic and 80 mm Hg or higher systolic (a definition, it should be noted, that has attracted some controversy).

Based on these guidelines, the following had hypertension by the age of 55:

• 77.5% of black men
• 77.7% of black women
• 54.5% of white men
• 40.0% of white women

Thomas said the findings have implications for the management of younger African American patients. "It is urgent that heathcare providers counsel young patients, particularly blacks, about eating a healthy diet, being physically active and controlling body weight," he said.

Higher body weight was associated with an increased risk for hypertension, regardless of race or gender. Following a DASH-style diet high in fruits, vegetables and whole grains and low in red meat and salt was associated with a lower risk for high blood pressure.

Thomas noted that given that racial differences in hypertension emerged before age 30 years, prevention efforts aimed at lowering high blood pressure risk should be considered for African Americans at a young age.

At baseline, the mean age of the participants included in the analysis was 24.7 years, 42.4% were men and half (49.3%) were black.

Compared to whites, blacks in the analysis were younger, had fewer years of education, were less physically fit, and were less likely to consume moderate-to-heavy amounts of alcohol and adhere to the DASH diet and more likely to smoke cigarettes and have a parental history of hypertension. Blacks also had a higher mean BMI and systolic BP and lower mean serum uric acid level compared to whites at baseline.

Over 30 years of follow-up, just over half of participants overall developed hypertension.

Adjusted hazard ratios for African Americans versus whites to develop hypertension were also stratified according to different blood pressure ranges at baseline:

• <110/70: HR 1.97 (95% CI 1.65-2.35)
• 110-119/70-74: HR 1.80 (95% CI 1.52-2.14)
• 120-129/75-79: HR 1.59 (95% CI 1.31-1.93)

Parental history of hypertension and higher body mass index, serum uric acid, and systolic blood pressure/diastolic blood pressure categories were associated with a higher risk for hypertension among blacks and whites.

Thomas and colleagues noted that the higher incidence of hypertension in blacks was consistent with earlier cross-sectional and longitudinal studies, including previous analyses of the CARDIA study cohort.

They concluded that while their findings support recommendations calling for early prevention to reduce hypertension risk later in life, such intervention "may not fully eliminate disparities in hypertension incidence by race."

"Risk for developing hypertension was much higher in blacks compared with whites, regardless of baseline BP level, even after multivariable adjustment," the researchers noted. "Given the interaction of genetic and environmental factors in determining one's risk for hypertension, more-detailed genotyping, as well as phenotyping of risk factors associated with the development of hypertension, may help identify the reasons underlying this racial disparity in hypertension."

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