Relationship between serum 25-hydroxyvitamin D and target organ damage in children with essential hypertension

Latest Knowledge on the Role of Vitamin D in Hypertension

Hypertension is the third leading cause of the global disease burden, and while populations live longer, adopt more sedentary lifestyles, and become less economically concerned, the prevalence of hypertension is expected to increase. Pathologically elevated blood pressure (BP) is the strongest risk factor for cardiovascular disease (CVD) and related disability, thus making it imperative to treat this disease. Effective standard pharmacological treatments, i.e., diuretics, angiotensin converting enzyme (ACE) inhibitors, angiotensin receptor blocker (ARBs), beta-adrenergic receptor blockers (BARBs), and calcium channel blockers (CCBs), are available. Vitamin D (vitD) is known best for its role in bone and mineral homeostasis. Studies with vitamin D receptor (VDR) knockout mice show an increased renin-angiotensin-aldosterone system (RAAS) activity and increased hypertension, suggesting a key role for vitD as a potential antihypertensive agent. Similar studies in humans displayed ambiguous and mixed results. No direct antihypertensive effect was shown, nor a significant impact on the human RAAS. Interestingly, human studies supplementing vitD with other antihypertensive agents reported more promising results. VitD is considered a safe supplement, proposing its great potential as antihypertensive supplement. The aim of this review is to examine the current knowledge about vitD and its role in the treatment of hypertension.

Association between red blood cell distribution width and left ventricular hypertrophy in pediatric essential hypertension

AIM

Left ventricular hypertrophy (LVH) is one of the most common types of target organ damage in hypertension. The red blood cell distribution width (RDW) is closely related to many cardiovascular diseases, including hypertension. The aim of this study was to analyze the relationship between the RDW level and LVH in pediatric essential hypertension.

MATERIALS AND METHODS

A total of 429 untreated children and adolescents with essential hypertension were recruited and divided into an LVH group (n = 114) and non-LVH group (n = 315) according to left ventricular mass index (LVMI) and relative wall thickness (RWT) by color Doppler ultrasound. Spearman correlation analysis was used to determine the relationship between RDW and LVMI, RWT. The effect of RDW on LVH was determined using a multivariate logistic regression analysis. To assess the predictive value of RDW on LVH, the receiver operating characteristic (ROC) curve was used.

RESULTS

The level of RDW in children with hypertension in the LVH group was significantly higher than that in the non-LVH group (13.0 [12.0, 13.0] vs. 12.4 [12.0, 13.0] %, P = 0.001). The incidence of low and high quantiles of LVH was 21.0% and 32.0%, respectively. Spearman correlation analysis showed that RDW was positively correlated with C-reactive protein (CRP), LVMI, RWT, and red blood cell (RBC) count (P all < 0.05), and negatively correlated with hemoglobin (HGB) level, mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC) (P all < 0.05). After adjusting for various confounding factors, a multivariate logistic regression model revealed that RDW was an independent risk factor for LVH (OR = 1.946, 95% CI: 1.324-2.861, P = 0.001). The area under the ROC curve of RDW predicting centripetal hypertrophy was 0.700 (95% CI: 0.541-0.859, P < 0.05) in pediatric essential hypertension.

CONCLUSIONS

Increased RDW levels are an independent risk factor for LVH in pediatric essential hypertension, and RDW may be a predictor of LVH in untreated pediatric essential hypertension.

Prevalence of left ventricular hypertrophy in children and young people with primary hypertension: Meta-analysis and meta-regression

BACKGROUND

Left ventricular hypertrophy (LVH) is the main marker of HMOD in children and young people (CYP). We aimed to assess the prevalence of LVH and its determinants in CYP with primary hypertension (PH).

METHODS

A meta-analysis of prevalence was performed. A literature search of articles reporting LVH in CYP with PH was conducted in Medline, Embase, and Cochrane databases. Studies with a primary focus on CYP (up to 21 years) with PH were included. Meta-regression was used to analyze factors explaining observed heterogeneity.

RESULTS

The search yielded a total of 2,200 articles, 153 of those underwent full-text review, and 47 reports were included. The reports evaluated 51 study cohorts including 5,622 individuals, 73% male subjects, and a mean age of 13.6 years. LVH was defined as left ventricle mass index (LVMI) ≥ 95th percentile in 22 (47%), fixed cut-off ≥38.6 g/m2.7 in eight (17%), sex-specific fixed cut-off values in six (13%), and miscellaneously in others. The overall prevalence of LVH was 30.5% (95% CI 27.2-33.9), while heterogeneity was high (I 2 = 84%). Subgroup analysis including 1,393 individuals (76% male subjects, mean age 14.7 years) from pediatric hypertension specialty clinics and LVH defined as LVMI ≥95th percentile only (19 study cohorts from 18 studies), reported prevalence of LVH at 29.9% (95% CI 23.9 to 36.3), and high heterogeneity (I 2 = 84%). Two studies involving patients identified through community screening (n = 1,234) reported lower LVH prevalence (21.5%). In the meta-regression, only body mass index (BMI) z-score was significantly associated with LVH prevalence (estimate 0.23, 95% CI 0.08-0.39, p = 0.004) and accounted for 41% of observed heterogeneity, but not age, male percentage, BMI, or waist circumference z-score. The predominant LVH phenotype was eccentric LVH in patients from specialty clinics (prevalence of 22% in seven studies with 779 participants) and one community screening study reported the predominance of concentric LVH (12%).

CONCLUSION

Left ventricular hypertrophy is evident in at least one-fifth of children and young adults with PH and in nearly a third of those referred to specialty clinics with a predominant eccentric LVH pattern in the latter. Increased BMI is the most significant risk association for LVH in hypertensive youth.