Somatotype and blood pressure of rural South African children aged 6-13 years: Ellisras longitudinal growth and health study

A demographic approach to assess elevated blood pressure and obesity in prepubescent children: the ExAMIN Youth South Africa study

BACKGROUND

Obesity and hypertension prevalence among children are a concern, with limited evidence available on sex and ethnic differences in childhood blood pressure. We aimed to determine the number of children with hypertension and obesity to identify unique adiposity and blood pressure characteristics by sex and ethnicity, and to estimate the odds of having elevated blood pressure with increasing adiposity.

METHODS

We included 1062 healthy children (5-9 years of age) in an observational school-based study in South Africa. Pediatric validated automated devices were used to measure brachial blood pressure and performed pulse wave analysis to assess central hemodynamics. Standard anthropometry was carried out to determine body composition and demographic questionnaires were completed.

RESULTS

Almost 20% of children were overweight/obese and 14.1% had elevated blood pressure or hypertension (22.8%). Ethnic differences included greater adiposity in white compared with black children (all P < 0.0001), but higher DBP and total vascular resistance in black compared with white children (both P < 0.05). DBP and total vascular resistance were also higher in girls than boys (both P < 0.01). A 51-60% increased risk of developing elevated blood pressure was observed for 1SD (standard deviation) increase of sex-specific BMI [1.60 (1.4-1.8); P < 0.0001] and waist/height ratio [1.51 (1.3-1.7); P < 0.0001].

CONCLUSION

Unique sex and ethnic differences in body composition and blood pressure exist in prepubescent children, with overweight/obesity increasing the risk of elevated blood pressure. Our findings support primary prevention strategies to combat the growing burden of hypertension and obesity-related diseases in youth.

TRIAL REGISTRATION

The study is registered on ClinicalTrials.gov (NCT04056377).

Weight status, cardiorespiratory fitness and high blood pressure relationship among 5-12-year-old Chinese primary school children

Cardiorespiratory fitness (CRF) and adiposity contribute to high blood pressure (HBP) in adults and children. However, their relative importance as risk factors is unknown. We examined the relationships between weight status, CRF and HBP among Chinese primary school children. A cross-sectional study was conducted with 4926 school children aged 5-12 years. CRF was estimated from a modified Cooper test, body mass index z-scores and weight categories were calculated from objective height and weight measurements and BP was measured using an electronic sphygmomanometer. HBP was defined as >95th percentile based on reference cutoffs for Chinese boys and girls. Generalised Linear Mixed models, adjusting for age, pubertal status and height, were developed for boys and girls to explore the independent and combined associations between fitness, weight status and HBP. Seven hundred and fifty-two (15.3%) children had HBP, with a higher prevalence in obese (40.5% and 45.9% in boys and girls, respectively) and overweight (27.6% and 30.2% in boys and girls, respectively) compared with non-overweight (9.0% and 13.8% in boys and girls, respectively) children. HBP prevalence was lower in boys with higher CRF (odds ratio (OR) for the highest vs lowest CRF quartile in boys 0.64; 95% confidence interval (CI) 0.46-0.89). This association was not seen in girls. With weight status and CRF in the same model, weight status, but not CRF, remained significantly associated with HBP (obesity in boys: OR 4.19; 95% CI 2.63-6.67; in girls: OR 2.49; 95% CI 1.19-5.19). The interaction effect for CRF and weight status was non-significant. Overweight/obesity was significantly associated with HBP among children. There was no evidence of modification of this relationship by CRF.

Multilevel modelling of somatotype components: the Portuguese sibling study on growth, fitness, lifestyle and health

BACKGROUND

Somatotype is a complex trait influenced by different genetic and environmental factors as well as by other covariates whose effects are still unclear.

AIMS

To (1) estimate siblings' resemblance in their general somatotype; (2) identify sib-pair (brother-brother (BB), sister-sister (SS), brother-sister (BS)) similarities in individual somatotype components; (3) examine the degree to which between and within variances differ among sib-ships; and (4) investigate the effects of physical activity (PA) and family socioeconomic status (SES) on these relationships.

SUBJECTS AND METHODS

The sample comprises 1058 Portuguese siblings (538 females) aged 9-20 years. Somatotype was calculated using the Health-Carter method, while PA and SES information was obtained by questionnaire. Multi-level modelling was done in SuperMix software.

RESULTS

Older subjects showed the lowest values for endomorphy and mesomorphy, but the highest values for ectomorphy; and more physically active subjects showed the highest values for mesomorphy. In general, the familiality of somatotype was moderate (ρ = 0.35). Same-sex siblings had the strongest resemblance (endomorphy: ρ_SS > ρ_BB > ρ_BS; mesomorphy: ρ_BB = ρ_SS > ρ_BS; ectomorphy: ρ_BB > ρ_SS > ρ_BS). For the ectomorphy and mesomorphy components, BS pairs showed the highest between sib-ship variance, but the lowest within sib-ship variance; while for endomorphy BS showed the lowest between and within sib-ship variances.

CONCLUSIONS

These results highlight the significant familial effects on somatotype and the complexity of the role of familial resemblance in explaining variance in somatotypes.

Childhood adiposity trajectories are associated with late adolescent blood pressure: birth to twenty cohort

BACKGROUND

Elevated blood pressure in childhood is a risk factor for adult hypertension which is a global health problem. Excess adiposity in childhood creates a predisposition to develop adult hypertension. Our aim was to explore distinct sex-specific adiposity trajectories from childhood to late adolescence and examined their association with blood pressure.

METHODS

Latent Class Growth Mixture Modeling (LCGMM) on longitudinal data was used to derive sex-specific and distinct body mass index (BMI: kg/m(2)) trajectories. We studied 1824 black children (boys = 877, girls = 947) from the Birth to Twenty (Bt20) cohort from Soweto, South Africa, and obtained BMI measures at ages 5 through 18 years. Participants with at least two age-point BMI measures, were included in the analysis. Analysis of variance (ANOVA), chi-square test, multivariate linear and standard logistic regressions were used to test study characteristics and different associations.

RESULTS

We identified three (3) and four (4) distinct BMI trajectories in boys and girls, respectively. The overall prevalence of elevated blood pressure (BP) was 34.9 % (39.4 % in boys and 30.38 % in girls). Boys and girls in the early onset obesity or overweight BMI trajectories were more likely to have higher BP values in late adolescence. Compared to those in the normal weight BMI trajectory, girls in early onset obesity trajectories had an increased risk of elevated BP with odds ratio (OR) of 2.18 (95 % confidence interval 1.31 to 4.20) and 1.95 (1.01 to 3.77). We also observed the weak association for boys in early onset overweight trajectory, (p-value = 0.18 and odds ratio of 2.39 (0.67 to 8.57)) CONCLUSIONS: Distinct weight trajectories are observed in black South African children from as early as 5 years. Early onset adiposity trajectories are associated with elevated BP in both boys and girls. It is important to consider individual patterns of early-life BMI development, so that intervention strategies can be targeted to at-risk individuals.

Evidence of an overweight/obesity transition among school-aged children and youth in Sub-Saharan Africa: a systematic review

BACKGROUND

Prevalence of childhood overweight/obesity has increased considerably in recent years. The transition to higher rates of overweight/obesity has been well documented in high income countries; however, consistent or representative data from lower income countries is scarce. It is therefore pertinent to assess if rates of overweight/obesity are also increasing in lower income countries, to inform public health efforts.

OBJECTIVE

This systematic review aimed to investigate the evidence for an overweight/obesity transition occurring in school-aged children and youth in Sub Saharan Africa.

METHODS

Studies were identified by searching the MEDLINE, Embase, Africa Index Medicus, Global Health, Geobase, and EPPI-Centre electronic databases. Studies that used subjective or objective metrics to assess body composition in apparently healthy or population-based samples of children and youth aged 5 to 17 years were included.

RESULTS

A total of 283 articles met the inclusion criteria, and of these, 68 were used for quantitative synthesis. The four regions (West, Central, East, and South) of Sub Saharan Africa were well represented, though only 11 (3.9%) studies were nationally representative. Quantitative synthesis revealed a trend towards increasing proportions of overweight/obesity over time in school-aged children in this region, as well as a persistent problem of underweight. Weighted averages of overweight/obesity and obesity for the entire time period captured were 10.6% and 2.5% respectively. Body composition measures were found to be higher in girls than boys, and higher in urban living and higher socioeconomic status children compared to rural populations or those of lower socioeconomic status.

CONCLUSIONS

This review provides evidence for an overweight/obesity transition in school-aged children in Sub Saharan Africa. The findings of this review serve to describe the region with respect to the growing concern of childhood overweight/obesity, highlight research gaps, and inform interventions.

PROSPERO REGISTRATION NUMBER

CRD42013004399.

Comparison of blood pressure levels among children and adolescents with different body mass index and waist circumference: study in a large sample in Shandong, China

PURPOSE

Several anthropometric indicators [such as body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR)] have been used to investigate the association between adiposity and high blood pressure (BP) in both adults and children. The present study compared the BP levels among children and adolescents with different BMI and WC in a large population in Shandong, China.

METHODS

A total of 38,822 students (19,456 boys and 19,366 girls) aged 7-17 years participated in this study. Height, weight, WC, and BP of all subjects were measured, and BMI was calculated. The prevalence of overweight and obesity was obtained according to the International Obesity Task Force (IOTF) cutoffs; central obesity was defined as WC ≥ 90th percentile (P 90); relatively high BP status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥ 95th percentile for age and gender.

RESULTS

Within each BMI categories (normal weight, overweight, and obesity), children and adolescents with WC ≥ P 90 had higher BP levels than those with WC < P 90 (p < 0.01). When BMI and WC were combined, the highest and lowest prevalences of relatively high BP were noted in obese with WC ≥ P 90 group (54.52% for boys and 48.71% for girls) and normal weight with WC < P 90 group (17.00% for boys and 14.13% for girls).

CONCLUSION

Children and adolescents with high BMI and high WC might have an increased risk of elevated BP. Our results suggest that the additional measurement of WC is better than BMI alone to help identify high BP risks.

Índice de massa corpórea, sobrepeso e pressão arterial em escolares na província de Limpopo, África do Sul

OBJETIVO: Avaliar a relação entre índice de massa corporal, sobrepeso e pressão arterial em crianças e adolescentes da área rural da África do Sul. MÉTODOS: A amostra abrangeu 1.172 escolares (541 meninos e 631 meninas) com idades entre 10 e 16 anos. Estatura, massa corporal e dobras cutâneas foram medidas por meio de procedimentos padrão. O sobrepeso foi definido pelo índice de massa corporal para idade e sexo. A pressão arterial foi monitorada três vezes em cada criança com o uso de aparelhos eletrônicos validados (Omron HEM-705 CP, Omron, Tóquio, Japão). A hipertensão foi determinada como a média de três leituras da pressão arterial, em que a sistólica ou a diastólica foi igual ou acima do percentil 90 para idade e sexo. Estatísticas descritivas foram calculadas para todas as variáveis. RESULTADOS: A prevalência de sobrepeso foi de 5,5% para meninos e 4,4% para meninas. A taxa de crianças com pressão arterial acima do percentil 90 variou de 2,3 a 5,9%. A probabilidade do desenvolvimento de hipertensão em crianças é perceptível aos dez anos, tanto para os meninos (0,2%) quanto para as meninas (0,1%), e oscilou de 0,2 a 1,7% para o sexo masculino e de 0,1 a 1,2% para o feminino. Considerando-se a amostra total, a prevalência de hipertensão foi de 4,1% para os meninos e 2,8% para as meninas. A pressão arterial apresentou correlação positiva com estatura, massa corporal, índice de massa corporal, gordura corpórea e soma das dobras cutâneas (p<0,001). CONCLUSÕES: A pressão arterial aumentou com a idade tanto para os meninos quanto para as meninas. A medição da pressão arterial de rotina, como parte do exame físico em escolares, é crucial para fins de prevenção e medidas de intervenção precoces.

Physical activity, fitness and the metabolic syndrome in rural youths from Mozambique

BACKGROUND

Except for North America and Europe, few studies have reported the association among physical activity (PA), cardiorespiratory fitness (CRF) and metabolic syndrome (MetS) in youths, especially for rural African youth.

AIM

The aims of this study were to determine the prevalence of PA levels, CRF, MetS and its indicators, and examine the association between these variables in a school-aged sample of youth from rural Mozambique.

SUBJECTS AND METHODS

The sample included 209 children and adolescents aged 7-15 years old from Calanga, a rural community in Mozambique. PA was estimated with a culturally-specific questionnaire. CRF was determined by 1-mile run test. Indicators of the MetS included fasting glucose, triglycerides, total cholesterol, blood pressure and body mass index. A continuous metabolic risk score was computed.

RESULTS

Results showed high levels of PA and CRF and a low prevalence of MetS ( < 2%) among children and adolescents from Calanga. However, there was a moderately high prevalence of elevated blood pressure (81.8%) and triglycerides (18.7%), respectively. There were no significant associations between PA, CRF and MetS.

CONCLUSION

Youths from Calanga are physically active and possess high CRF and their lifestyle may be a protective effect against MetS.

Monitoring of blood pressure among children and adolescents in a coastal province in China: results of a 2010 survey

BACKGROUND

Several studies have provided ample evidence that hypertension in adults has its onset in childhood; children and adolescents with elevated blood pressure (BP) are more likely to become hypertensive adults. The present study examined the prevalence of relatively high BP among children and adolescents in Shandong, China.

SUBJECTS AND METHODS

Data for this study were obtained from a large cross-sectional survey of schoolchildren carried out in 2010. A total of 38 860 students (19 481 boys and 19 379 girls) aged 7 to 17 years participated in this study. Relatively high BP status was defined as systolic blood pressure and/or diastolic blood pressure ≥95th percentile for age and gender.

RESULTS

Shandong children had a high BP level, with the 50th percentiles of systolic and diastolic blood pressure of children and adolescents aged 7 to 17 years in Shandong being above the reference values for Chinese children and adolescents by 3 to 12 mm Hg and 3 to 7 mm Hg for boys, and by 3 to 6 mm Hg and 3 to 5 mmHg for girls, respectively. The overall prevalence of relatively high BP was 26.22% for boys and 20.27% for girls.

CONCLUSION

There is a high prevalence of relatively high BP among children and adolescents in Shandong, China. It has become a threatening hazard to children and adolescents and should arouse special attention.

Distribution of body composition index and the relationship with blood pressure among children aged 7 to 12 years in Shandong, China

Body mass index (BMI) is widely used to assess the prevalence of childhood obesity in populations, and the relationship of BMI with blood pressure has been observed. However, no study has reported on the distribution of body composition index and the relationship with blood pressure. The present study examined the distribution of body composition index and the relationship with blood pressure among children aged 7 to 12 years in Shandong, China. A total of 4326 students (2165 boys and 2161 girls) aged 7 to 12 years participated in this study. Height, weight, skinfold thickness, and blood pressure of all the subjects were measured. Body fat percentage (BF%) was calculated by regression equation, and fat mass index (FMI) and fat-free mass index (FFMI) were calculated according to following expressions: FMI = BF% × weight/height(2) and FFMI = (weight - BF% × weight)/height(2). The 50th percentile values of FMI and FFMI increased with age in both sexes. The mean values of FFMI were significantly higher in boys than in girls (P < .01), but no statistically significant differences in mean FMI between the 2 sexes were observed (P > .05). Both systolic blood pressure and diastolic blood pressure were significantly positively related to FMI and FFMI in both boys and girls (P < .05). FMI and FFMI are potentially useful in evaluating the body composition of individuals with different stature. There is a strong positive relationship between FMI and blood pressure in children; these findings emphasize the importance of the prevention of obesity in children and adolescents.

A systematic overview of prospective cohort studies of cardiovascular disease in sub-Saharan Africa

Background

Cardiovascular diseases (CVDs) are becoming increasingly significant in sub-Saharan Africa (SSA). Reliable measures of the contribution of major determinants are essential for informing health services and policy solutions.

Objective

To perform a systematic review of all longitudinal studies of CVDs and related risk factors that have been conducted in SSA.

Data source

We searched electronic databases from 1966 to October 2009. Published studies were retrieved from PubMed and Africa EBSCO. Reference lists of identified articles were scanned for additional publications.

Study selection

Any longitudinal study with data collection at baseline on major cardiovascular risk factors or CVD, including 30 or more participants, and with at least six months of follow up were included.

Data extraction

Data were extracted on the country of study, year of inception, baseline evaluation, primary focus of the study, outcomes, and number of participants at baseline and final evaluation.

Results

Eighty-one publications relating to 41 studies from 11 SSA countries with a wide range of participants were included. Twenty-two were historical/prospective hospital-based studies. These studies focused on risk factors, particularly diabetes mellitus and hypertension, or CVD including stroke, heart failure and rheumatic heart disease. The rate of participants followed through the whole duration of studies was 72% (64–80%), with a significant heterogeneity between studies (for heterogeneity, p < 0.001). Outcomes monitored during follow up included trajectories of risk markers and mortality.

Conclusions

Well-designed prospective cohort studies are needed to inform and update our knowledge regarding the epidemiology CVDs and their interactions with known risk factors in the context of common infectious diseases in this region.

The relationship of body mass index distribution to relatively high blood pressure among children and adolescents in Shandong, China

BACKGROUND

Obesity and hypertension are both common health problems in children and adolescents; several studies have reported that obesity is associated with elevated blood pressure (BP) in both adults and children. However, no studies on the association between body mass index (BMI) distribution and prevalence of relatively high BP among children and adolescents have been reported in China.

AIM

The present study examined the relationship of BMI distribution to relatively high BP among children and adolescents in Shandong, China.

SUBJECTS AND METHODS

A total of 8568 students (4,333 boys and 4,235 girls) aged 7-18 years participated in this study. Height, weight and BP of all subjects were measured; BMI of adolescents was calculated from their height and weight. Relatively high BP status was defined as systolic blood pressure (SBP) and/or diastolic blood pressure (DBP) ≥ 95th percentile for age and gender. Prevalence of relatively high BP within each BMI percentile category was determined. Comparisons of BP among different BMI percentile groups were made.

RESULTS

The levels of SBP and DBP increased with age and were positively correlated with BMI in both boys and girls. The overall prevalence of relatively high BP was 24.07% for boys and 22.36% for girls. Prevalence of relatively high BP increased with BMI percentiles, this trend being especially obvious in the upper percentiles of BMI. An increasing trend was observed in SBP and DBP from BMI < 25th, 25th ≤ BMI < 50th, 50th ≤ BMI < 75th to BMI ≥ 75th percentile group.

CONCLUSION

There is a high prevalence of relatively high BP among children and adolescents in Shandong, China. The present findings emphasize the importance of prevention of overweight and obesity in order to prevent future related problems such as hypertension in children and adolescents.

Relation of body mass index, fat mass index and fat-free mass index to blood pressure in children aged 7-12 in Shandong, China

BACKGROUND

Body mass index (BMI) is widely used to assess the prevalence of childhood obesity in populations and its relationship with blood pressure has been observed. However, no studies on the distribution of fat mass index (FMI) and fat-free mass index (FFMI) and their relationship with blood pressure have been reported.

AIM

The present study examined the distribution of BMI, FMI, FFMI and the relationship with blood pressure among children aged 7-12 years in Shandong, China.

SUBJECTS AND METHODS

A total of 4326 children (2165 boys and 2161 girls) aged 7-12 years participated in this study. Height, weight, skinfold thickness (SFT) and blood pressure (BP) of all subjects were measured, body fat percentages (BF%) were calculated by regression equation, fat mass index (FMI) and fat-free mass index (FFMI) were calculated according to the following expressions: FMI (kg/m(2)) = BF% × weight/height(2) and FFMI (kg/m(2)) = (weight - BF% × weight)/height(2).

RESULTS

SBP and DBP were positively correlated with FMI, FFMI and BMI in both boys and girls, the strongest correlation observed for BP was with FMI. The prevalence of relatively high BP increased with FMI percentiles, this trend being especially obvious in upper percentiles of FMI. The prevalence of relatively high BP increased from 3.74% (boys) and 7.48% (girls) in the < 5th FMI percentile group to 56.19% (boys) and 50.94% (girls) in the ≥ 95th FMI percentile group, an increase of 14.0- and 5.8-times.

CONCLUSION

There is a strong positive relationship between FMI and BP in children; the correlation between BP and FMI was stronger than with FFMI and BMI.

High blood pressure in children: clinical and health policy implications

Hypertension is a global problem, affecting both developed and developing nations. In addition to being a major cause of morbidity and mortality, hypertension places a heavy burden on health care systems, families, and society as a whole. Despite evidence of an increasing prevalence of hypertension among youth, the consequences of early onset are poorly established and often overlooked. Childhood hypertension is often asymptomatic and easily missed, even by health professionals. Target organ damage is detectable in children and adolescents, however, and hypertension continues into adulthood. Additional strategies to improve cardiovascular health among children and adolescents are needed, including methods to achieve healthy lifestyles at home and in school, improved systems for diagnosis, and research on mechanisms and timing of interventions. The burden of hypertension in the young will continue to grow unless it is given the attention it deserves by policy makers, health care providers, schools, parents, and society. This report aims to increase awareness of the problem of hypertension in childhood. Recent reports on prevalence and target organ injury are discussed and health policy initiatives to improve blood pressure control are proposed.