Vitamin D levels in white coat and sustained hypertension.

OBJECTIVE

The plasma levels of vitamin D in patients with white coat hypertension (WCHT) have not been studied previously. The aim of this study was to evaluate vitamin D levels in WCHT and compare with sustained hypertension (SHT) and with normotension (NT).

PATIENTS AND METHODS

Fifty-three normotensive, 42 WCHT, and 59 SHT patients were recruited in this study. The participants were matched for age, sex, and BMI. The vitamin D levels were determined using the electrochemiluminescence immunoassay method.

RESULTS

Plasma vitamin D levels were significantly lower in SHT than in the WCHT and NT groups (26.4±4.9, 34.3±3.6, and 36±5 ng/ml, respectively), and were similar in the WCHT and NT groups. There was a negative correlation between vitamin D levels and blood pressure parameters such as clinic systolic blood pressure (SBP), clinic diastolic blood pressure (DBP), 24-h SBP, 24-h DBP, daytime SBP, daytime DBP, night-time SBP, and night-time DBP (r=-0.554, -0.419, -0.629, -0.427, -0.559, -0.534, -0.607, -0.462, respectively, and all P<0.001) in the entire study group. Clinic SBP (B±SE=-0.97±0.037, P=0.009) and 24-h SBP (B±SE=-0.138±0.055, P=0.013) were identified as predictors for vitamin D levels in the entire study group.

CONCLUSION

Our data show that sustained hypertensive patients have lower vitamin D levels than white coat hypertensive and normotensive individuals. White coat hypertensive patients without other cardiovascular risk factors have higher vitamin D levels than sustained hypertensive patients, suggesting that they have a lower cardiovascular risk.