Exploring A Potential Relation Between Vitamin D And Blood Pressure Variability In Young Black Women

Vitamin D (VitD) deficiency and cardiovascular diseases (CVD), e.g., high blood pressure (BP), are known to disproportionately affect Black women (BLW), yet BLW remain an understudied population. Elevated BP is also associated with increased CVD risk, and studies in middle-aged and older adults suggest a causal role for VitD in BP regulation. Increases in beat-to-beat blood pressure variability (bBPV) have been reported to precede elevated BP. However, there are limited data on bBPV in young BLW, and whether VitD is associated with bBPV in young BLW is currently unknown. PURPOSE: To (1) characterize bBPV in young BLW and (2) to explore a potential relation between VitD, BP, and bBPV. We hypothesized that lower serum VitD concentrations would be associated with higher BP and bBPV. METHODS: Participants included healthy young BLW ages 18-30 yrs. Serum VitD concentration was assessed from a fasted venous blood sample. Morning supine resting brachial BP was measured in triplicate and averaged. Beat-to-beat BP was collected concurrently over 5 minutes during spontaneous breathing using continuous noninvasive arterial pressure photoplethysmography of the index finger (n = 32). bBPV was calculated as standard deviation (SD), average real variability (ARV) and coefficient of variation (CV). RESULTS: No significant associations between VitD and morning resting BP were observed. Associations between VitD and parameters of systolic bBPV were trending in the hypothesized direction [SD (r = -0.30;p = 0.097), ARV (r = -0.31;p = 0.086), and CV (r = -0.33;p = 0.069)]. There were significant negative associations between VitD and diastolic bBPV for SD (r = -0.40; p = .02) and ARV (r = -0.39;p = 0.032) but a trend for CV (r = -0.32;p = 0.084). CONCLUSION: Preliminary results revealed weak-to-moderate inverse associations between VitD and parameters of resting diastolic bBPV, with similar observed trends for systolic bBPV. BPV is an emerging biomarker of BP regulation that may precede elevations in BP, especially in young and at-risk groups. The identification of a potential relation between VitD and BPV in young BLW is important as BLW are at increased risk of CVD and VitD deficiency. Further studies are needed to better understand the mechanisms behind the relation between VitD and its impact on autonomic control of cardiovascular function. Supported by: NIH 1R01HLI55764 (MW) and The University of Delaware Doctoral Fellowship for Excellence (MD)