Exploring the Link Between Markers of Arterial Health and Urinary Dopamine in South African Adults: The SABPA Study

Background Urinary dopamine enhances blood pressure (BP) regulation by promoting natriuresis, vasodilation, and anti-inflammatory effects while lowering renal oxidative stress. Ethnicity-related differences in sodium handling, sympathetic activity, and subsequently renin-angiotensin-aldosterone system (RAAS) are well-known. Limited knowledge exists with regards to urinary dopamine and its association with arterial health. We aimed to examine the association of urinary dopamine with arterial health measures including pulse wave velocity (PWV), carotid intima-media thickness (CIMT), reactive oxygen species (ROS), and endothelin-1 (ET-1), in Black and White adults. Methods We included adults aged 20–65 years ( n = 278) stratified by ethnicity, Black ( n = 110) and White ( n = 168). An 8-hour urine sample was collected, followed by analysis of creatinine, sodium, potassium, dopamine, and its metabolites, 3,4-hydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA). We also measured vascular health measures including PWV, CIMT, ROS, and ET-1. Results Systolic and diastolic BP measures and CIMT were higher in the Black than the White group ( p ≤ 0.045). Urinary dopamine levels were comparable between the groups, while HVA and DOPAC along with ROS and CRP were higher in the Black individuals ( p < 0.001). A positive independent association between CIMT and urinary dopamine was observed in the White group only (β = 0.166; p = 0.007). In the Black group CIMT associated positively and independently with HVA (β = 0.100; p = 0.036). Conclusion CIMT associated positively with urinary dopamine in the White group, while in the Black group CIMT associated positively with HVA, which may reflect heightened oxidative stress-driven urinary dopamine turnover. These findings highlight ethnicity-specific mechanisms linking urinary dopamine to vascular remodelling.