Association between vitamin D deficiency and adrenal gland, kidney function, indicators related to cardiovascular...

Previous research has established an association between vitamin D deficiency and various non-skeletal metabolic disorders. However, the potential association between vitamin D status and specific clinical manifestations including renal dysfunction, primary aldosteronism (PA), and cardiovascular function-related indicators in patients with hypertension remains poorly elucidated.

A total of 250 consecutive patients with hypertension who were hospitalized in the Senior Cardiology Department of the Sixth Medical Center of the Chinese PLA General Hospital were enrolled in this study. Volunteers currently supplementing with vitamin D have been excluded. Fasting peripheral venous blood samples were collected from all participants for routine biochemical assays. All participants underwent a comprehensive set of examinations, including transthoracic echocardiography, ambulatory blood pressure monitoring, and routine urinalysis. Serum levels of 25-hydroxyvitamin D (25-OH-D) were measured to evaluate vitamin D status. Relevant clinical and physiological indicators were recorded. Differences in auxiliary examination results and physiological indicators between subgroups were compared and analyzed. The correlations of serum 25-OH-D levels with renal function parameters, cardiovascular function-related indicators, and PA status were further investigated.

Of all participants, 165 patients had vitamin D deficiency (serum 25-OH-D < 50 nmol/L), whereas 85 patients had non-deficient vitamin D status (serum 25-OH-D ≥ 50 nmol/L). There were no statistically significant differences in age, gender, and body mass index (BMI) between the two groups. Compared with the non-deficient group, patients in the vitamin D deficiency group (25-OH-D < 50 nmol/L) had significantly lower levels of hematocrit, red blood cell count, hemoglobin, serum calcium, urinary uric acid, and urinary creatinine, as well as significantly higher levels of serum sodium, supine aldosterone concentration, supine aldosterone-to-renin ratio (ARR), and upright aldosterone concentration (all p < 0.05). Binary logistic regression analysis revealed that PA was significantly associated with vitamin D deficiency (OR 0.210, 95% CI 0.045-0.974, p = 0.046). Multivariate linear regression analysis demonstrated that serum 25-OH-D levels were independently and inversely associated with estimated glomerular filtration rate (eGFR) (β = -4.348, t = -3.082, p = 0.002). Patients with chronic kidney disease (CKD) had a significantly larger left atrial anteroposterior diameter [39(36,42) vs. 36(32,39) mm, p = 0.001] and pulmonary artery diameter [24(22,26) vs. 23(21,25) mm, p = 0.010], along with a higher 24-h mean systolic blood pressure (131 ± 11 vs. 127 ± 11 mmHg, p = 0.042), but a lower 24-h mean diastolic blood pressure (73 ± 10 vs. 77 ± 9 mmHg, p = 0.042), compared with those without renal dysfunction.

After adjustment for traditional cardiovascular risk factors, PA remained independently associated with vitamin D deficiency in patients with hypertension. Vitamin D and retinol-binding protein were significantly associated with renal dysfunction in this patient population.