Sociodemographic and Kidney Disease Correlates of Nutrient Intakes Among Urban African Americans With Uncontrolled Hypertension

Abstract

Objective: The objective of this study was to determine the association between sociodemographic factors and intakes of 4 nutrients and associations between intakes and markers of kidney disease to identify opportunities to improve outcomes among clinically high-risk African Americans.

Design and methods: We conducted a cross-sectional study of baseline data from the Achieving Blood Pressure Control Together study, a randomized controlled trial of 159 African Americans (117 females) with uncontrolled hypertension in Baltimore MD. To determine the association between sociodemographic factors and nutrient intakes, we constructed linear and logistic regression models. Using logistic regression, we determined the association between below-median nutrient intakes and kidney disease. Our outcomes of interest were daily intakes of vitamin C, magnesium, dietary fiber, and potassium as estimated by the Block Fruit-Vegetable-Fiber Screener and kidney disease defined as estimated glomerular filtration rate <60 mL/min per 1.73 m2 or urinary albumin-to-creatinine ratio >=30 mg/g.

Setting and subjects: Baseline data from the Achieving Blood Pressure Control Together study, a randomized controlled trial of 159 African Americans (117 females) with uncontrolled hypertension, were obtained.

Methods: To determine the association between sociodemographic factors and nutrient intakes, we constructed linear and logistic regression models. Using logistic regression, we determined the association between below-median nutrient intakes and kidney disease.

Main outcome measures: Our outcomes of interest were daily intakes of vitamin C, magnesium, dietary fiber, and potassium as estimated by the Block Fruit-Vegetable-Fiber Screener and kidney disease defined as estimated glomerular filtration rate <60 mL/min per 1.73 m² or urinary albumin-to-creatinine ratio ≥30 mg/g.

Results: Overall, compared to Institute of Medicine recommendations, participants had lower intakes of magnesium, fiber, and potassium but higher vitamin C intakes. For females, sociodemographic factors that significantly associated with lower intake of the 4 nutrients were older age, obesity, lower health numeracy, and lesser educational attainment. For males, none of the sociodemographic factors were significantly associated with nutrient intakes. Below-median intake was significantly associated with albumin-to-creatinine ratio ≥30 (adjusted odds ratio [95% confidence interval]: 3.4 [1.5, 7.8] for vitamin C; 3.6 [1.6, 8.4] for magnesium; 2.9 [1.3, 6.5] for fiber; 3.6 [1.6, 8.4] for potassium), but not with estimated glomerular filtration rate <60.

Conclusion: African Americans with uncontrolled hypertension may have low intakes of important nutrients, which could increase their risk of chronic kidney disease. Tailored dietary interventions for African Americans at high risk for chronic kidney disease may be warranted.