Performance of blood pressure to height ratio as a screening tool for elevated blood pressure in rural children: Ellisras Longitudinal Study

Paediatric Hypertension in Africa: A Systematic Review and Meta-Analysis

BACKGROUND

The burden of cardiovascular disease (CVD) and hypertension is rapidly increasing in low- and middle-income countries. This is evident not only in adults, but also in children. Recent estimates of prevalence in children are lacking, particularly in Africa. As such, we conducted a systematic review and meta-analysis to provide updated estimates of paediatric hypertension in Africa.

METHODS

We searched PubMed and EBSCO to identify articles published from January 2017 to November 2020. Studies were assessed for quality. We combined results for meta-analyses using a random effects model (Freeman-Tukey arcsine transformation). Heterogeneity was quantified using the I² statistic.

FINDINGS

In the narrative synthesis of 53 studies, publication bias was low for 28, moderate for 24, and high for one study. Hypertension prevalence ranged substantially (0·2%-38·9%). Meta-analysis included 41 studies resulting in data on 52918 participants aged 3 to 19 years from ten countries. The pooled prevalence for hypertension (systolic/diastolic BP≥95th percentile) was 7·45% (95%CI 5·30-9·92, I²=98.96%), elevated blood pressure (BP, systolic/diastolic BP≥90th percentile and <95th percentile) 11·38% (95%CI 7·94-15·33, I²=98.97%) and combined hypertension/elevated BP 21·74% (95%CI 15·5-28·69, I²=99.48%). Participants categorized as overweight/with obesity had a higher prevalence of hypertension (18·5% [95%CI 10·2-28·5]) than those categorized as underweight/normal (1·0% [95%CI 0·1-2·6], 4·8% [95%CI 2·9-7·1], p<0·001). There were significant differences in hypertension prevalence when comparing BP measurement methods and classification guidelines.

INTERPRETATION

Compared to a previous systematic review conducted in 2017, this study suggests a continued increase in prevalence of paediatric hypertension in Africa, and highlights the potential role of increasing overweight/obesity.

FUNDING

This research was funded in part by the Wellcome Trust [Grant number:214082/Z/18/Z]. LJW and SAN are supported by the DSI-NRF Centre of Human Development at the University of the Witwatersrand.

Can Anthropometry and Body Composition Explain Physical Fitness Levels in School-Aged Children?

Physical fitness (PF) is closely related to various health outcomes and quality of life among children. However, the associations between anthropometry, body composition (BC), and PF are not fully elucidated. This cross-sectional study aimed to investigate the associations between demographic metrics (age, sex), anthropometric measures (body mass index z-score (BMI z-score) waist/height ratio (WHtR)), BC parameters (body-fat percentage (BF%), muscle weight), and PF levels (800-m run, sit-and-reach, 1-min sit-ups, standing long jump) in school-aged children. Continuous variables were dichotomized by median splits. The results of 180 girls and 180 boys (mean age: 10.0 ± 0.7 years; mean BMI z-score: 0.366 ± 1.216) were analyzed. Multivariable linear regressions revealed that BF% (regression coefficient (B) = 3.4, 95% confidence interval (CI) = 2.5-4.3) was independently correlated with the 800-m run. Sex (B = 4.6, 95% CI = 3.0-6.3), age (B = 3.1, 95% CI = 1.9-4.3), and BMI z-score (B = -0.7, 95% CI = -1.4--0.1) were independently related to sit-and-reach. Age (B = 3.3, 95% CI = 2.0-4.7), BF% (B = -0.3, 95% CI = -0.4--0.2), and muscle weight (B = 0.7, 95% CI = 0.2-1.2) were independently associated with 1-min sit-ups. In addition to demography, anthropometry and BC provided additional information concerning some PF levels in school-aged children. Weight management and PF promotion should be addressed simultaneously in terms of preventive medicine and health promotion for children.

Are Body Composition Parameters Better than Conventional Anthropometric Measures in Predicting Pediatric Hypertension?

Body composition (BC) parameters are associated with cardiometabolic diseases in children; however, the importance of BC parameters for predicting pediatric hypertension is inconclusive. This cross-sectional study aimed to compare the difference in predictive values of BC parameters and conventional anthropometric measures for pediatric hypertension in school-aged children. A total of 340 children (177 girls and 163 boys) with a mean age of 8.8 ± 1.7 years and mean body mass index (BMI) z-score of 0.50 ± 1.24 were enrolled (102 hypertensive children and 238 normotensive children). Significantly higher values of anthropometric measures (BMI, BMI z-score, BMI percentile, waist-to-height ratio) and BC parameters (body-fat percentage, muscle weight, fat mass, fat-free mass) were observed among the hypertensive subgroup compared to their normotensive counterparts. A prediction model combining fat mass ≥ 3.65 kg and fat-free mass ≥ 34.65 kg (area under the receiver operating characteristic curve = 0.688; sensitivity = 66.7%; specificity = 89.9%) performed better than BMI alone (area under the receiver operating characteristic curve = 0.649; sensitivity = 55.9%; specificity = 73.9%) in predicting hypertension. In conclusion, BC parameters are better than anthropometric measures in predicting pediatric hypertension. BC measuring is a reasonable approach for risk stratification in pediatric hypertension.

Using blood pressure height index to define hypertension among secondary school adolescents in southwestern Uganda

Hypertension is the number one risk factor for cardiovascular diseases worldwide and yet its diagnosis among adolescents, based on blood pressure percentiles which are age, height, and sex-specific, is complex. Our study intended to determine the suitability of blood pressure height index in defining adolescent hypertension among secondary school adolescents aged 12-17 years in Mbarara municipality, southwestern Uganda. Our study used data of 485 secondary school adolescents of which 173 were boys. Receiver operating characteristic curve analysis was performed to assess the performance of systolic blood pressure height index (SBPHI) and diastolic blood pressure height index (DBPHI) for screening for adolescent prehypertension and hypertension. The optimal systolic/diastolic thresholds for defining prehypertension were 0.70/0.43 mmHg/cm in boys and 0.76/0.43 in girls. The corresponding values for hypertension were 0.78/0.43 and 0.77/0.48 mmHg/cm, respectively. The negative predictive values were much higher (all ≥ 95%) for prehypertension and hypertension, while the positive predictive value was 100% for hypertension in both sexes. In conclusion, Blood pressure height index is simple and accurate for screening for prehypertension and hypertension in adolescents aged 12-17 years hence can be used for early screening of adolescents at high risk of hypertension but not its diagnosis.