The relationship between body composition and blood pressure among primary school children in Eastern Cape province, South Africa

Associations of early childhood body mass index trajectories with body composition and cardiometabolic markers at age 10 years: the Ethiopian infant anthropometry and body composition (iABC) birth cohort study

BACKGROUND

Variability in body mass index (BMI) (kg/m2) trajectories is associated with body composition and cardiometabolic markers in early childhood, but it is unknown how these associations track to later childhood.

OBJECTIVES

We aimed to assess associations of BMI trajectories from 0 to 5 y with body composition and cardiometabolic markers at 10 y.

METHODS

In the Ethiopian infant anthropometry and body composition (iABC) birth cohort, we previously identified 4 distinct BMI trajectories from 0 to 5 y: stable low BMI (19.2%), normal BMI (48.8%), rapid growth to high BMI (17.9%), and slow growth to high BMI (14.1%). At 10 y, we obtained data from 320 children on anthropometry, body composition, abdominal subcutaneous and visceral fat, and cardiometabolic markers. Associations of BMI trajectories and 10-y outcomes were analyzed using multiple linear regression.

RESULTS

Compared with children with the normal BMI trajectory, those with rapid growth to high BMI had 1.7 cm (95% CI: 0.1, 3.3) larger waist circumference and those with slow growth to high had 0.63 kg/m2 (95% CI: 0.09, 1.17) greater fat mass index and 0.19 cm (95% CI: 0.02, 0.37) greater abdominal subcutaneous fat, whereas those with stable low BMI had -0.28 kg/m2 (95% CI: -0.59, 0.03) lower fat-free mass at 10 y. Although the confidence bands were wide and included the null value, children with rapid growth to high BMI trajectory had 48.6% (95% CI: -1.4, 123.8) higher C-peptide concentration and those with slow growth to high BMI had 29.8% (95% CI: -0.8, 69.8) higher insulin and 30.3% (95% CI: -1.1, 71.6) higher homeostasis model assessment of insulin resistance, whereas those with rapid growth to high BMI had -0.23 mmol/L (95% CI: -0.47, 0.02) lower total cholesterol concentration. The trajectories were not associated with abdominal visceral fat, blood pressure, glucose, and other lipids at 10 y.

CONCLUSIONS

Children with rapid and slow growth to high BMI trajectories before 5 y tend to show higher measures of adiposity and higher concentrations of markers related to glucose metabolism at 10 y.

CLINICAL TRIAL REGISTRY

ISRCTN46718296 (https://www.isrctn.com/ISRCTN46718296).

Influence of puberty on relationships between body composition and blood pressure: a cross-sectional study

BACKGROUND

Fat mass (FM) and fat-free mass (FFM) are positively associated with blood pressure (BP) in youth. Yet, how puberty, independent of age, affects these relationships remains unclear. Given puberty may be a crucial period for cardiometabolic health, we examined how pubertal development moderates the associations of FM/FFM with BP.

METHODS

Pubertal development, resting BP, and body composition were assessed in a convenience sample of youth (5.5-17 years). General linear models were conducted to assess if pubertal development moderated the relationships between FM/FFM and systolic/diastolic BP standardized for age, sex, and height (SBPz/DBPz).

RESULTS

Among participants (N = 1405; age: M = 13.3 ± 2.9 years; 65.4% female; 53.2% racial/ethnic minority), FM/FFM were positively associated with SBPz and DBPz (ps ≤ 0.02). Pubertal development moderated the associations between FFM and BPz (ps ≤ 0.01), but not FM (ps > 0.43). For early/mid and late pubertal participants, there were positive associations between FFM and BP (DBPz: βs = 0.10-0.18, ps ≤ 0.01; SBPz: βs = 0.33-0.43, ps < 0.001); however, these relationships were attenuated, especially for prepubertal DBPz (DBPz: β = 0.01, p = 0.91; SBPz: β = 0.24, p = 0.001).

CONCLUSIONS

Puberty moderated the relationships between FFM and SBPz/DBPz in analyses that separately modeled the contributions of age and sex. These data suggest that the FFM-DBPz association may potentially be impacted by increasing sex hormone concentrations during puberty.

IMPACT

Fat mass (FM) and blood pressure (BP) were positively associated throughout puberty. Fat-free mass (FFM) and BP were positively associated throughout puberty; however, puberty moderated the FFM-BP relationship, such that there was a positive relationship in early/mid and late puberty, but the relationship was attenuated for prepubertal children. These findings contribute further insight into physiological and cardiometabolic changes occurring during puberty. Changes in hormone concentrations may explain the impact puberty has on the FFM-BP relationship. Understanding predictors of BP are important as childhood BP is associated with future cardiometabolic outcomes.

Patterns and predictors of elevated blood pressure and hypertension among primary school children in urban Kenya

OBJECTIVE

We examined the prevalence of elevated blood pressure (BP) and hypertension among 390 primary school children of different socioeconomic status (SES) in two urban settings in Kenya and explored the association between children's BP status and their sociodemographic characteristics, dietary behaviours and overweight/obesity status.

METHODS

Children's BP and anthropometric measurements were taken and parents, with the help of their children, completed questionnaires on the children's dietary behaviours. An average of three BP readings was used to calculate BP percentiles by age, sex and height. BMI-for-age z-scores, waist-circumference-to-height ratio and the sum of skinfold measures were calculated. We utilized prevalence ratio analysis to examine the association between BP and sociodemographic characteristics, dietary behaviours and overweight/obesity.

RESULTS

About 9% of the school children had elevated BP and 33% had stage 1 hypertension. Among overweight children, the proportion of children with elevated BP was 1.85-fold greater and the proportion of children with hypertension was 1.83-fold greater compared with children with healthy body weight. Similar patterns of significant associations were seen among obese children, children with central obesity and children with high total skinfold values. The proportion of children with hypertension was 1.42-fold greater among children with high frequency of consumption of chips/crisps compared with children with lower frequency of consumption.

CONCLUSION

These results increase our understanding BP patterns and determinants among school children in Kenya and can help inform noncommunicable disease prevention efforts.

Relationship between body composition and physical fitness of primary school learners from a predominantly rural province in South Africa

Background

There is a lack of literature regarding the relationship that exists between body composition and physical fitness amongst primary school learners in South Africa. For the sake of public health purposes, it is important to investigate how body composition relates to physical fitness amongst primary school learners in the Eastern Cape province of South Africa.

Aim

The aim of this study was to examine the relationship between body composition and physical fitness amongst South African primary school children.

Setting

The study was conducted on a cohort of primary school learners in the Eastern Cape province, which is a predominantly rural province in South Africa.

Methods

A school-based cross-sectional survey was conducted amongst 870 primary schoolchildren aged 9–14 years. Body composition and physical fitness measurements were measured and recorded using standardised measurement scales.

Results

Of the 870 participants, 40.34% (n = 351) were boys and 59.66% (n = 519) were girls. The mean age of the participants was 11.04 ± 1.50 years. Boys had a significantly (p = 0.002) higher mean age (11.24 ±1.51 years) as compared to girls (10.91 ± 1.48 years). The results of the non-parametric Spearman’s rho correlation coefficients revealed several significant and negative relationships between physical fitness and body composition measurements, which were stronger in girls than in boys.

Conclusion

The findings call for public health authorities and other relevant policymakers to initiate the development and implementation of policies and interventions targeted at encouraging physical activity participation and healthy lifestyle amongst primary school learners in South Africa, especially amongst girls.

Contribution

The study findings supports a relatively rich literature which suggests that girls are more flexible than boys and that negative relationships between body composition measurements and physical fitness characteristics exists, which are stronger in girls than in boys.

Blood pressure profile of primary school children in Eastern Cape province, South Africa: prevalence and risk factors

Abstract

Background

The problem of cardiovascular diseases and lack of adequate information about the blood pressure profiles among children in South Africa has enormous consequences for public health and the general well-being of communities.

Aim

The aim of this study is to determine the blood pressure profiles and associated risk factors of primary school children in South Africa.

Methods

A cross sectional study was conducted among 876 children aged 9 to 14 years from 18 randomly selected schools in the Eastern Cape province of South Africa. Standardised blood pressure measuring instruments were used and an average of three readings was considered. Blood pressure status was classified according to the percentiles of systolic blood pressure (SBP).

Results

The overall prevalence of hypertension was 5.2% and pre-hypertension was 18.5% while normal blood pressure was 76.3%. The multilevel binary logistic regression’s crude and adjusted analysis revealed that increase in age was significantly associated with elevated BP in children ([crude OR = 1.17 [1.05 – 1.29] and [adjusted OR = 1.12 [1.01 – 1.25]). In addition, increase in BMI was significantly associated with elevated BP in children ([crude OR = 1.08 [1.04 – 1.12] and [adjusted OR = 1.06 [1.02 – 1.11]). There was no statistically significant association between elevated BP and gender for both the univariate and multivariate models. There was also no statistical significant risk for elevated BP associated with place of residence.

Conclusions

In this sampled population the established proportion of primary school children with elevated BP is of great concern. In addition, older children and those with high BMI (that is, overweight/obesity) were associated with elevated BP. Interventions towards promoting healthy lifestyles among school learners is a necessity if we are to prevent cardiovascular diseases.

Practice Change Needed for the Identification of Pediatric Hypertension in Marginalized Populations: An Example From South Africa

INTRODUCTION

Hypertension in children has increased globally over the past 20 years; yet, little is known about this issue among disadvantaged communities from low- and middle-income countries. Age-, sex-, and height-adjusted normative tables are the "gold" standard for the diagnosis and estimation of pediatric hypertension worldwide, but it is unclear whether the use of international standards is appropriate for all contexts. The purpose of this study was to evaluate and compare different international references to identify hypertension among South African school-aged children from disadvantaged communities.

METHODS

Blood pressure, weight, and height were measured in a cohort of 897 children aged 8-16 years from eight peri-urban schools in the Eastern Cape of South Africa. Cross-sectional prevalence of hypertension was calculated according to American, German, and global normative tables, as well as pseudo-normative data from the own study population. Isolated systolic hypertension and body mass index (BMI) were considered markers for cardiovascular disease. Multinomial logistic regression was used to compare the likelihood of blood pressure categorization with increasing BMI levels.

RESULTS

Hypertension prevalence ranged from 11.4% with the pseudo-normative study tables to 28.8% based on the German reference. Global guidelines showed the highest agreement both among international standards (92.5% with American guidelines) and with the study reference (72.5%). While the global and the American references presented higher systolic over diastolic hypertension rates (23.6 vs. 10.6% and 24.2 vs. 14.7%, respectively), the American guidelines predicted the highest increased risk for hypertension stage 2 [odds ratio, 1.72 (95% confidence interval: 1.43-2.07)] with raising levels of BMI.

CONCLUSION

Our results support the heterogeneity of blood pressure estimates found in the South African literature, and highlight the underrepresentation of African children in international guidelines. We call for caution in the use of international standards in different contexts and advocate for the development of normative tables that are representative of the South African pediatric population necessary to ensure an accurate identification of hypertension both from the clinical and epidemiological perspective.

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.

Association between Body Fat and Elevated Blood Pressure among Children and Adolescents Aged 7-17 Years: Using Dual-Energy X-ray Absorptiometry (DEXA) and Bioelectrical Impedance Analysis (BIA) from a Cross-Sectional Study in China

To investigate the associations between body fat percentage (BF%) with childhood blood pressure (BP) levels and elevated BP (EBP) risks, and further examine the validity of bioelectrical impedance analysis (BIA), we conducted a cross-sectional study of 1426 children and adolescents aged 7–17 years in Beijing, 2020. EBP, including elevated systolic BP (ESBP) and elevated diastolic BP (EDBP), was defined based on the age- and sex-specific 90th BP reference values of children and adolescents in China. BF% was measured by dual-energy X-ray absorptiometry (DEXA) and BIA devices, and was divided into four quartiles. Log-binomial models were applied to calculate odds ratios (ORs) and 95% confidence intervals (95%CI). Girls tended to have higher BF% levels than boys (p < 0.05). There was 41.0% of girls who developed EBP. High BF% was associated with increased BP levels with ORs of 0.364 (95%CI = 0.283–0.444) for SBP, 0.112 (95%CI = 0.059–0.165) for DBP, and 1.043 (95%CI = 1.027–1.059) for EBP, while the effects were more pronounced in girls and older-aged children. BIA devices agreed well with BF% assessment obtained by DEXA. High BF% might have negative effects on childhood BP. Convenient measurements of body fat might help to assess childhood obesity and potential risks of hypertension.

Diagnostic Precision of Anthropometric Variables for the Detection of Hypertension in Children and Adolescents

Introduction: High blood pressure (HBP) is a health problem the prevalence of which has increased in young populations. Overweight and obesity in early ages have been directly related to its development. Due to the impact of HBP, it is necessary to provide tools that facilitate its early diagnosis, with useful anthropometric variables being those that assess obesity. The objective of this paper was to determine the diagnostic accuracy of anthropometric variables to detect HBP. Methods: A cross-sectional study was conducted on 265 students aged 6-16. The diagnosis of HBP was made following the criteria proposed by the Spanish Association of Pediatrics. Through different statistical methods, the association between anthropometric variables of general obesity with HBP was analyzed. Results: Waist circumference (WC) showed the best diagnostic capacity (area under the receiver operating characteristic curve = 0.729), with a sensitivity and specificity of 72.2% and 76%, respectively, for a cut-off point of 73.5 cm. In the adjusted multivariate analysis, an association was found between HBP and anthropometric variables: WC (odds ratio (OR) = 10.7), body mass index (OR = 7.5), waist-to-height ratio (OR = 5.5) and body fat percentage (OR = 5.3) (p < 0.05). Conclusions: The anthropometric variables studied showed a moderate predictive capacity for HBP, highlighting WC, which showed the strongest association with HBP in the infant and child population.

An Assessment of the Relationship between Anthropometric Parameters and Blood Pressure among Polokwane Private School Children

High blood pressure (HBP) among children and adolescents has been associated with elevated risk of cardiovascular diseases later in life. The aim of this study was to determine the relationship between body composition and blood pressure among Polokwane private school children. Mean body fat % was significantly (P < 0.05) higher in girls (23.74) than the boys (16.77). There was a significant (P < 0.05) association between systolic blood pressure (BP) and waist circumference (WC) unadjusted (OR = 1.125) and adjusted (OR = 1.097) for age and gender. This study included a total of 1665 children and adolescents (846 boys and 819 girls) aged 5 to 15 years old. Anthropometric measurements including weight, height, hip circumference (HC) and waist circumference (WC) were taken according to standard procedures. Descriptive statistics were done to determine the prevalence of hypertension and mean of all the variables. Pearson correlation, linear regression and logistic regression were all done to determine the association between blood pressure (BP) and the anthropometric measurements. All statistical analysis were done using SPSS. There was a significant association between body composition and blood pressure among Polokwane Private School children. Lowering the risk factors of high BP in children and adolescents will lower their risk of cardiovascular diseases in adulthood.