Waist-to-height-ratio is associated with sustained hypertension in children and adolescents with high office blood pressure

Background

Waist-to-height-ratio (WHtR) has been proposed as another indicator for cardiometabolic risk factors including hypertension. Normally, hypertension can be diagnosed in the office setting by detecting high blood pressure for three occasions. However, patients with high office blood pressure may not exhibit high blood pressure outside the office. Ambulatory blood pressure monitoring (ABPM) is a procedure to measure blood pressure over 24-h. Sustained hypertension is characterized as hypertension detected by both office measurement and ABPM. This study aimed to evaluate the performance of WHtR in the diagnosis of sustained hypertension in patients with high office blood pressure.

Materials and methods

Demographic data, height, body weight, body mass index (BMI), and waist circumference were retrospectively reviewed in children and adolescents who underwent ABPM due to persistently high office blood pressure. Patients were separated into two groups: a sustained hypertension group and a normal ABPM group. BMI was adjusted to z-score using the WHO Anthroplus software. WHtR was calculated by the formula: waist circumference (cm)/height (m). The performances of different parameters were analyzed using the receiver operating characteristic (ROC) curve and multivariate logistic regression.

Results

Sixty patients (63% male) with a mean age of 12.9 ± 3.7 years had persistently high office blood pressure. Twenty-nine (48.3%) had high ambulatory blood pressure parameters so-called "sustained hypertension." The sustained hypertension group had a higher mean BMI z-score (2.32 vs. 1.31, p = 0.01) and a higher mean WHtR (57.7 vs. 49.2 cm/m, p < 0.001) than those of the normal ABPM group. For the diagnosis of sustained hypertension, the ROC analysis revealed that WHtR had a greater area under the ROC curve (AUC) than that of BMI z-score (0.772 vs. 0.723). WHtR remained associated with sustained hypertension (OR 1.2, 95% CI 1.022-1.408, p = 0.026) after adjusting for age, gender, and BMI z-score.

Conclusions

Apart from being a more user-friendly metric, WHtR tended to outperform BMI z-score in predicting sustained hypertension in children and adolescents with persistently high office blood pressure.

Age as a major factor associated with zinc and copper deficiencies in pediatric thalassemia

BACKGROUND

Patients with thalassemia encounter increased consumption of zinc (Zn) and copper (Cu) from chronic hemolysis and increased excretion from iron chelation. Iron-enriched diet restriction may result in low Zn and Cu intakes. Recent data on Zn and Cu status among Thai pediatric patients with thalassemia are lacking. This study aimed to identify frequencies and determine risk factors of Zn and Cu deficiencies among patients with thalassemia.

METHODS

Patients with transfusion-dependent thalassemia (TDT) receiving iron chelation ≥12 months and nonTDT (NTDT) aged 2-20 years were recruited. Serum Zn and Cu were measured. Dietary intakes were ascertained by interviews.

RESULTS

A total of 209 patients (TDT = 126, NTDT = 83) were enrolled. Zn deficiency seemed to be associated with disease severity as median (IQR) Zn level of TDT was lower than that of NTDT [77 (69-85) vs. 80 (72-88) mcg/dL, p = 0.05], while higher frequency of Zn deficiency was identified in the former (24 % vs. 14 %). In TDT, Zn deficiency was associated with patients >10 years (OR 4.6; 95 %CI 1.1-6.4, p = 0.03), which likely resulted from combined low dietary Zn intake, prolonged exposures to hemolysis and iron chelators. Frequencies of Cu deficiency were similarly low in TDT and NTDT (8% and 7%) with comparable median (IQR) Cu levels of 103 (90-124) and 110 (92-132) mcg/dL, respectively (p = 0.13). Cu levels were inversely associated with age (r=-0.65 and r=-0.62 in TDT and NTDT, respectively; p < 0.001).

CONCLUSION

Compared with younger patients, Zn and Cu deficiencies were more common among patients with thalassemia >10 years. Age was a major factor associated with both Zn and Cu deficiencies.