Measurements of adiposity and high blood pressure among children and adolescents living in Belo Horizonte

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.

Measurement of Central Aortic Blood Pressure in Youth: Role of Obesity and Sex

BACKGROUND

The relationship between pediatric severe obesity (SO) and central aortic blood pressure (BP) has yet to be established.

METHODS

We conducted a cross-sectional study of 348 youth (48.5% male, age 12.7 ± 0.1 years) with a wide range of body mass index (BMI) values: normal weight (NW; ≥5th and <85th BMI percentiles), overweight/obesity (OW/OB; 85th to <120% of the 95th BMI percentile), and SO (≥120% of the 95th BMI percentile). Measures of central aortic BP were obtained via applanation tonometry with SphygmoCor MM3 software.

RESULTS

After adjustment for covariates, no significant sex differences were observed for radial-aortic systolic blood pressure (SBP) (P = 0.39), carotid-aortic SBP (P = 0.99), radial-aortic diastolic blood pressure (DBP) (P = 0.44), and carotid-aortic DBP (P = 0.53). Compared to youth with NW, youth with SO exhibited higher radial-aortic SBP (SO vs. NW: 102 ± 1 mm Hg vs. 90 ± 1 mm Hg, P<0.001), carotid-aortic SBP (SO vs. NW: 121 ± 1 mm Hg vs. 109 ± 1 mm Hg, P<0.001), and carotid-aortic DBP (SO vs. NW: 60 ± 1 mm Hg vs. 56 ± 1 mm Hg, P = 0.04). Compared to youth with OW/OB, youth with SO had higher radial-aortic SBP (OW/OB: 97 ± 1 mm Hg, P = 0.002) and carotid-aortic SBP (OW/OB: 114 ± 1 mm Hg, P = 0.007). After adjusting for either total-body percent fat mass or visceral adipose tissue, BMI was still a significant predictor of both radial-aortic and carotid-aortic SBP and DBP (P<0.001, all).

CONCLUSIONS

In a cohort of youth with a wide range of adiposity levels, central aortic BP was elevated among individuals with SO and associated with BMI but not body fatness.

Correlates of elevated blood pressure in healthy children: a systematic review

The prevalence of hypertension in children is increasing globally. Addressing this will require a robust understanding of associated risk factors. To this end, we conducted a systematic review to identify correlates of elevated blood pressure (BP) in children. Literature searches were conducted using pre-defined search terms from three academic databases. The abstract and full text of identified studies were screened for eligibility by two independent reviewers. A total of 100 studies were included in this systematic review. An assessment tool was first used to assess study quality; a narrative synthesis was then performed. We found a broad range of physiological, social and behavioural factors associated with elevated BP in children. The most common correlate observed was adiposity, suggesting that childhood obesity may be implicated in the increased prevalence of hypertension observed in children. However, the broad range of other factors identified underscores the multi-factorial aetiology of hypertension. Data from a broad range of studies showed that the correlates of hypertension in children are multi-factorial. Therefore, approaches aimed at preventing hypertension must in turn be multi-factorial to ensure that the burden of hypertension in childhood is addressed.

[Obesity: main risk factor for systemic arterial hypertension in Brazilian adolescents from a cohort study]

OBJECTIVE

To identify the prevalence and factors associated with hypertension in adolescents.

SUBJECTS AND METHODS

Cross-sectional study of 1,716 adolescents of a cohort study, aged from 10 to 16 years old sociodemographic, economic, and lifestyle characteristics were obtained from an interview, and birth weight from hospital records. Hypertension was defined as systolic or diastolic blood pressure above the 95th percentile according to the classification recommended by the Second Task Force High Blood Pressure in Children and Adolescents. Nutritional status was diagnosed by body mass index (BMI), according to the z score from curves published by the World Health Organization. Waist circumference was measured at the natural waist. The association between hypertension and the explanatory variables was measured using logistic regression.

RESULTS

The adolescents interviewed represent 71.4% of the baseline, and 50.7% of them were males. The prevalence of hypertension was 11.7%. In the multivariate analysis, after adjustment for age sex and skin color, hypertension was associated with obesity [OR = 2.27, (95%) CI = 1.64 to 3.14] but not associated with waist circumference after adjusting for BMI. Early life factors were not associated with hypertension in adolescence.

CONCLUSION

The results show an association between obesity and hypertension among adolescents.

Selected anthropometric variables and aerobic fitness as predictors of cardiovascular disease risk in children

The aim of this study was to assess the suitability of body mass index, waist circumference, waist-to-height ratio and aerobic fitness as predictors of cardiovascular risk factor clustering in children. A cross-sectional study was conducted with 290 school boys and girls from 6 to 10 years old, randomly selected. Blood was collected after a 12-hour fasting period. Blood pressure, waist circumference (WC), height and weight were evaluated according to international standards. Aerobic fitness (AF) was assessed by the 20-metre shuttle-run test. Clustering was considered when three of these factors were present: high systolic or diastolic blood pressure, high low-density lipoprotein (LDL) cholesterol, high triglycerides, high plasma glucose, high insulin concentrations and low high-density lipoprotein (HDL) cholesterol. A ROC curve identified the cut-off points of body mass index (BMI), WC, waist-to-height ratio (WHtR) and AF as predictors of risk factor clustering. BMI, WC and WHR resulted in significant areas under the ROC curves, which was not observed for AF. The anthropometric variables were good predictors of cardiovascular risk factor clustering in both sexes, whereas aerobic fitness should not be used to identify cardiovascular risk factor clustering in these children.

Anthropometric measures and blood pressure in school children

OBJECTIVE

To investigate the association of blood pressure and body mass index, waist circumference, waist-to-height ratio and triceps skinfold, in children and adolescents in Curitiba, state of Paraná, Brazil.

METHODS

Cross-sectional study with a random sample of 1,441 students from public schools, aged from 10 to 16 years (655 boys and 786 girls). The following indicators were assessed: weight, height, waist circumference, triceps skinfold, systolic and diastolic blood pressures, pubertal stage, and socioeconomic status. Pearson correlation tests and multivariate logistic regression were used, considering p<0.05.

RESULTS

We found weak correlations among all the anthropometric parameters and systolic and diastolic levels, with coefficients values ranging from 0.18 to 0.28 (p<0.001). In multivariate analysis, only body mass index [odds ratio (OR)=2.9; 95% confidence interval (95%CI) 1.9-4.5] and triceps skinfold (OR=1.9; 95%CI 1.3-3.1) were found as predictors of high blood pressure, regardless of abdominal adiposity, sexual maturation and socioeconomic status.

CONCLUSION

Total body adiposity seems to be a better predictor of high blood pressure risk than abdominal fat in this population.

Gender-specific prevalence and associated risk factors of prehypertension among rural children and adolescents in Northeast China: a cross-sectional study

Little is known about the prevalence and risk profile of prehypertension among Chinese children and adolescents. The aim of the present study was to investigate the prehypertensive status and its associated risk factors among rural Chinese children and adolescents. We conducted a cross-sectional study including 5,245 children and adolescents (2,732 boys and 2,513 girls) aged 5-18 years in Northeast China. Main anthropometric data and related information were collected. The overall prevalence of prehypertension and hypertension was 15 % and 20.2 %, respectively. The prevalence of prehypertension among boys was 15.7 %, compared to that of 14.2 % among girls (P = 0.256). After adjusting for age, race, weight status, waist circumference, triceps skinfold, family income, smoking and drinking status, boys aged 12-14 and 15-18 years had a 2.86- and 5.97-fold risk of prehypertension, respectively, compared to those aged 5-8 years. Overweight and obese boys had an increased risk of prehypertension in comparison to those with normal weight (overweight: odds ratio [OR] = 1.837, 95 % confidence interval [CI] 1.321-2.556; obese: OR = 2.941, 95 % CI 1.783-4.851). A larger triceps skinfold (≥90th percentile) was significantly related to increased odds of prehypertension (OR = 2.32; 95 % CI, 1.516-3.55) among boys. For girls, only older age was found to be a risk factor for prehypertension.

CONCLUSION

Pediatric prehypertension is highly prevalent in rural Northeast China. The risk factors for prehypertension differed among boys and girls. A more comprehensive risk profile of prehypertension among children and adolescents needs to be established for early prevention.

Body fat location and cardiovascular disease risk factors in overweight female adolescents and eutrophic female adolescents with a high percentage of body fat

BACKGROUND

Excessive body fat, mainly abdominal fat, is associated with higher cardiovascular risk. However, a fat localisation measurement that would be more indicative of risk in adolescents has not yet been established.

OBJECTIVE

This study was conducted in order to evaluate the correlation between body fat location measurements and cardiovascular disease risk factors in female adolescents.

MATERIALS AND METHODS

A total of 113 girls - 38 eutrophic according to their body mass index but with a high percentage of body fat, 40 eutrophic with adequate body fat, and 35 with excessive weight - were evaluated using 15 anthropometrical measurements and 10 cardiovascular risk factors.

RESULTS

The central skinfold was the best measurement for predicting variables such as glycaemia and high-density lipoprotein; waist circumference for insulin and homeostasis model assessment; coronal diameter for total cholesterol and low-density lipoprotein; sagittal abdominal diameter for triglycerides and leptin; hip circumference for blood pressure; and the central/peripheral skinfold ratio for homocysteine. The correlation between the measurements and the number of risk factors showed that waist circumference and the waist/stature ratio produced the best results.

CONCLUSIONS

The results suggest that the body fat distribution in adolescents is relevant in the development of cardiovascular risk factors. Simple measurements such as waist circumference and the waist/stature ratio were the best predictors of a risk of disease and they should therefore be associated with the body mass index in clinical practice in order to identify those adolescents at higher risk.

Adjusting adiposity and body weight measurements for height alters the relationship with blood pressure in children

BACKGROUND

Adiposity measures are associated with increased pediatric blood pressure (BP). However, this correlation can be confounded by the relationship of both variables to height. We evaluated whether adiposity and anthropometric measures were associated with pediatric BP before and after adjusting each value for height.

METHODS

Participants included 281 African-American (AA), European-American (EA), and Hispanic-American (HA) children aged 7-12 years. BP percentiles were calculated according to pediatric guidelines using the average of four measurements. Total fat mass was determined using dual-energy X-ray absorptiometry. Socioeconomic status (SES) was calculated with the Hollingshead index. Adiposity measures were indexed for height using log-log regression analysis. Partial correlations identified measures associated with BP. Linear regression was used to test the association of those measures with absolute BP, whereas logistic regression was used to evaluate the odds for hypertension.

RESULTS

More AAs (16.3%) presented with potential hypertension than EA (5.1%) or HA (2.7%) children. After adjusting for covariates, fat mass, body mass index, and waist circumference were positively significantly associated with absolute BP and hypertension in AA and EA children (P < 0.05). When these measures were height-indexed, only waist remained significantly positively associated with hypertension risk in these two groups. No measures were significantly associated with BP among HA children.

CONCLUSIONS

In this multiethnic pediatric population, waist circumference was the strongest significant adiposity predictor of hypertension risk among AA and EA children. Additional research is needed to determine which environmental and genetic factors contribute to pediatric hypertension, particularly among HA groups.