Southern diet singled out as top factor for racial gap in hypertension
Adherence to a “Southern diet” may be the biggest driver of racial disparities in hypertension rates among black and white adults in the U.S., according to a prospective cohort study published Oct. 2 in JAMA.
The study included 6,897 adults who were without hypertension at baseline but participated in follow-up visits a median 9.4 years later. By then, 46 percent of black participants had developed incident hypertension—defined as 140/90 mm Hg or the use of antihypertensive medications—compared to 33 percent of white participants.
Researchers led by George Howard, DrPH, performed mediation analyses of 12 clinical and social factors to determine which ones were responsible for the gaps in hypertension incidence. The variables included education level, heavy alcohol use, family income below $35,000, waist circumference, body mass index (BMI), dietary patterns and depression and stress measures.
Howard et al. found a Southern dietary pattern accounted for 51.6 percent of the excess risk among black men and 29.2 percent of the excess risk among black women when compared to their white counterparts.
The Southern diet score is graded on a continuous scale of -4.5 to 8.2, with higher scores equaling greater compliance to the diet. In the study, black men had the highest adjusted mean Southern diet score of 0.81, followed by black women (0.27), white men (-0.26) and white women (-0.57).
“The Southern diet … includes high intake of fried foods, organ meats, processed meats, egg and egg dishes, added fats, high-fat dairy foods, sugar-sweetened beverages, and bread,” explained Howard, with the department of biostatistics for the School of Public Health at the University of Alabama-Birmingham, and colleagues. “In other research, this dietary pattern was associated with increased risk of incident stroke, coronary heart disease, end-stage renal disease and chronic kidney disease, sepsis, cancer mortality, and cognitive decline. The Southern diet also has been shown to be a large mediating factor for the difference in stroke risk between black and white individuals.”
Other factors that were singled out as contributing to the hypertension gap between black men and white men were a higher dietary ratio of sodium to potassium and an education attainment of high school graduate or less. Each of those characteristics was associated with 12.3 percent of the excess hypertension risk among black males, the authors reported.
Those factors were also responsible for some of the excess risk among black women, but to varying degrees. Specifically, the following factors were associated with excess risk for that population:
- Southern dietary pattern: 29.2 percent
- Higher BMI: 18.3 percent
- Larger waist circumference: 15.2 percent
- Less adherence to the Dietary Approaches to Stop Hypertension Diet: 11.2 percent
- Income level of $35,000 or less: 9.3 percent
- Higher dietary ratio of sodium to potassium: 6.8 percent
- Education level of high school or less: 4.1 percent
“The findings herein identified more mediating factors of the racial difference in incident hypertension in women than men,” Howard and colleagues wrote. “This may be partially attributable to an observed stronger association of race with incident hypertension among women than men that would provide greater statistical power to detect mediating factors.”
The authors noted cardiovascular disease, including stroke, is the biggest contributor to mortality differences between blacks and whites in the U.S. Hypertension has been identified as the most important driver of that disparity, making it important to study specific factors that might explain the higher incidence of high blood pressure in the black population.
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.