Fetal growth and cardiovascular risk factors in Jamaican schoolchildren

Concordance of the Deuterium Dose to Mother Method and 24-Hour Recall to Measure Exclusive Breastfeeding at 6 Weeks Postnatally in Rural/Urban Setting in Jamaica

INTRODUCTION

The 2030 health agenda for the United Nations Sustainable Development Goals promote exclusive breastfeeding (EBF) for the first 6 months of life as a central step towards ensuring the survival of infants. As Jamaica attempts to achieve this goal, monitoring the rates of EBF is desirable. Currently, EBF rate is measured by questionnaires which are subject to recall and social desirability biases. We determined the rate of EBF using the Deuterium-oxide dose-to-mother (DTM) method and 24-h recall. The concordance of both methods and urban-rural differences of EBF were evaluated. Additionally, the growth of infants who were exclusively breastfed was compared to the infants who were mixed-fed.

METHODS

Sixty-one healthy mother-child pairs were followed from birth. EBF was measured at 6 weeks. Growth was determined using standard anthropometric measurements. Differences in means were assessed by independent t-test or ANOVA. The agreement between the DTM and 24-h recall method was assessed with the kappa statistic. Differences in anthropometry and location were determined using a repeated measure model approach.

RESULTS

Thirty (49%) women exclusively breastfed their infants with mean breast milk intake of 1024.3 ± 256.9 g/day. There was moderate agreement between the methods (Agreement 69%, kappa 0.37, p = 0.002). Rural women (65%) were more likely to practice exclusive breastfeeding. There was no significant difference between the growth of the exclusively breastfed infant and mixed-fed infants.

CONCLUSION

EBF rate was successfully measured using the DTM method. Women from urban settings are less likely to practice EBF. Further research may be needed to gain an in-depth understanding of the factors affecting breastfeeding practices in urban Jamaica.

HbA1c percentiles and the association between BMI, age, gender, puberty, and HbA1c levels in healthy German children and adolescents

OBJECTIVE

The measurement of glycated hemoglobin (HbA1c) represents one way to detect type 1 and 2 diabetes in children at an early stage. However, to date, variations in HbA1c levels are not fully understood, even in healthy children. With this in mind, the present study aimed to establish HbA1c reference values in healthy children and to investigate the influence of various independent variables.

STUDY DESIGN AND METHODS

Two thousand four hundred fifty-five healthy children and adolescents aged between 0.5 and 18 years participated in the population-based cohort study LIFE Child, Germany. Age- and gender-dependent percentiles were estimated, enabling HbA1c values to be converted into standard deviation scores (SDS). Logistic regression models were applied to assess associations between HbA1c-SDS (as outcome) and age, gender, BMI, birth weight, physical activity, pubertal status, and socioeconomic status (SES; as explanatory variables).

RESULTS

The mean HbA1c value was 31.79 mmol/mol or 5.06% (SD = 3.3 mmol/mol, SD = 0.3%). Positive associations with HbA1c values were identified for age (b = 0.09, p < 0.001), gender (b = 0.25, p = 0.007), and BMI-SDS (b = 0.06, p < 0.001). In addition, obesity was related to higher HbA1c values (b = 0.29, p < 0.001). Compared to prepuberty, the pubertal and postpubertal stages were associated with higher HbA1c levels. Furthermore, higher SES was associated with higher HbA1c-SDS (b = 0.01, p = 0.04).

CONCLUSION

The present study established HbA1c reference values based on a large sample of healthy German children and adolescents. Age, gender, SES, pubertal stage, and BMI were found to be associated with higher HbA1c levels.

Hyperglycemia and Adverse Pregnancy Outcome Follow-Up Study: newborn anthropometrics and childhood glucose metabolism

AIMS/HYPOTHESIS

We aimed to examine associations of newborn anthropometric measures with childhood glucose metabolism with the hypothesis that greater newborn birthweight, adiposity and cord C-peptide are associated with higher childhood glucose levels and lower insulin sensitivity.

METHODS

Data from the international, multi-ethnic, population-based Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study and the HAPO Follow-Up Study were used. The analytic cohort included 4155 children (mean age [SD], 11.4 [1.2] years; 51.0% male). Multiple linear regression was used to examine associations of primary predictors, birthweight, newborn sum of skinfolds (SSF) and cord C-peptide, from HAPO with continuous child glucose outcomes from the HAPO Follow-Up Study.

RESULTS

In an initial model that included family history of diabetes and maternal BMI during pregnancy, birthweight and SSF demonstrated a significant, inverse association with 30 min and 1 h plasma glucose levels. In the primary model, which included further adjustment for maternal sum of glucose z scores from an oral glucose tolerance test during pregnancy, the associations were strengthened, and birthweight and SSF were inversely associated with fasting, 30 min, 1 h and 2 h plasma glucose levels. Birthweight and SSF were also associated with higher insulin sensitivity (Matsuda index) (β = 1.388; 95% CI 0.870, 1.906; p < 0.001; β = 0.792; 95% CI 0.340, 1.244; p < 0.001, for birthweight and SSF higher by 1 SD, respectively) in the primary model, while SSF, but not birthweight, was positively associated with the disposition index, a measure of beta cell compensation for insulin resistance (β = 0.034; 95% CI 0.012, 0.056; p = 0.002). Cord C-peptide levels were inversely associated with Matsuda index (β = -0.746; 95% CI -1.188, -0.304; p < 0.001 for cord C-peptide higher by 1 SD) in the primary model.

CONCLUSIONS/INTERPRETATION

This study demonstrates that higher birthweight and SSF are associated with greater childhood insulin sensitivity and lower glucose levels following a glucose load, associations that were further strengthened after adjustment for maternal glucose levels during pregnancy. Graphical abstract.

Determinants of low birth weight in neonates born in three hospitals in Brong Ahafo region, Ghana, 2016- an unmatched case-control study

Background

Each year, about 20 million Low Birth Weight (LBW) babies are born with very high proportion (96.5%) occuring in developing countries. In the last decade, the incidence of LBW in Ghana has not declined. Brong Ahafo Region of Ghana recorded a LBW prevalence of 11% which was higher than the the national average of 10%. This study identifed determinants of LBW delivery in the Brong Ahafo Region.

Methods

We conducted a 1:2 unmatched case control study among mothers with singleton deliveries in 3 major health facilities in the Brong Ahafo Region. A case was defined as a mother who delivered a baby weighing less than 2500g in any of the three selected health facilities between 1st December, 2015 and 30th April, 2016. A control was defined as a mother who within 24 h of delivery by a case, delivered a baby weighing at least 2500g and not exceeding 3400g in the same health facility. Deliveries that met the inclusion criteria for cases were selected and two controls were randomly selected from the pool of deliveries that meet criteria for controls within 24 h of delivery of a case. A total of 120 cases and 240 control were recruited for the study. We computed odds ratios at 95% confidence level to determine the associations between low birth weight and the dependent factors.

Results

After controlling for confounders such as planned pregnancy, mode of delivery, parity and previous LBW in stepwise backward logistic regression, first trimester hemoglobin &lt; 11 g/dl (aOR 3.14; 95%CI: 1.50–6.58), delivery at 32-36 weeks gestation (aOR 13.70; 95%CI: 4.64–40.45), delivery below 32 weeks gestation (aOR 58.5; 95%CI 6.7–513.9), secondary education of mothers (aOR 4.19; 95%CI 1.45–12.07), living with extended family (aOR 2.43; 95%CI 1.15–5.10, living alone during pregnancy (aOR 3.9; 95%CI: 1.3–11.7), and not taking iron supplements during pregnancy (aOR 3.2; 95%CI: 1.1–9.5) were found to be significantly associated with LBW.

Conclusion

Determinants of LBW were: preterm delivery, mothers with secondary education, living alone during pregnancy, not taking daily required iron supplementation and mothers with first trimester hemoglobin below 11 g/dl. Education during antenatal sessions should be tailored to address the identified risk factors in the mother and child health care services.

Body Composition Growth Patterns in Early Infancy: A Latent Class Trajectory Analysis of the Ethiopian iABC Birth Cohort

OBJECTIVE

The objective of this study was to identify subgroups with distinct fat and fat-free growth patterns in the first 6 months of life and describe predictors of these different patterns.

METHODS

A total of 510 apparently healthy Ethiopian infants were followed from birth to 6 months of age. Each infant had at least three and up to six repeated measurements of fat and fat-free mass using air-displacement plethysmography. Latent class trajectory analyses were used to categorize infants in groups with distinct body composition patterns.

RESULTS

Four distinct fat mass and two fat-free mass growth patterns were identified. Of the infants measured, 5% presented a delayed fat growth pattern and 3% presented a catch-up fat growth pattern involving low birth weight but a significant fat growth velocity from 2.5 to 6 months. A large class had a high fat level at birth and an accelerated fat growth pattern in early infancy. Fat-free growth was represented by two distinct classes with less variability. Catch-up growth was primarily seen in fat mass.

CONCLUSIONS

We identified distinct patterns of delayed, catch-up, and accelerated fat growth in early infancy. This variability is not detected in regular anthropometric assessment and could be a mechanism linking early growth with later obesity and cardiometabolic risk.

[Blood pressure profile in adolescents at school in Lubumbashi, Democratic Republic of the Congo]

Introduction

L'objectif de cette étude était de donner le profil de la pression artérielle (PA) des adolescents âgés de 15 à 19 ans en milieu scolaire à Lubumbashi, République Démocratique du Congo.

Méthodes

il s'agit d'une étude transversale, portant sur les adolescents âgés de 15 à 19 ans au moyen d'un échantillonnage aléatoire des écoles secondaires de Lubumbashi durant les années scolaires 2013-2014, 2014-2015 et 2015-2016. Trois mesures de PA étaient effectuées le même jour.

Résultats

1766 adolescents âgés de 15-19 ans ont été inclus parmi eux 995 étaient de sexe féminin et 771 garçons. Les garçons avaient significativement une pression artérielle systolique élevée que les filles dans les tranches d'âges de 17, 18 et 19 ans. La pression artérielle diastolique n'était pas différente statistiquement dans toutes les tranches d'âges dans les deux sexes. Par contre, dans les deux sexes, la pression artérielle systolique été en corrélation significative avec le poids, la taille, l'indice de masse corporelle, le tour de taille et la fréquence cardiaque. Quant à la pression artérielle diastolique, des corrélations significatives étaient retrouvées avec le poids et l'indice de masse corporelle chez les filles alors que la fréquence cardiaque était en corrélation significative dans les deux sexes.

Discussion

Au cours de notre étude, il était question de déterminer les valeurs moyennes de PA et sa corrélation avec les paramètres anthropométriques, la FC et le poids de naissance chez les adolescents d'âge compris entre 15 et 19 ans. Notre étude a révélé des valeurs moyennes de PAS chez les garçons qui étaient plus élevées que les filles statistiquement significatives dans les tranches d'âges de 17, 18 et 19 ans alors que les valeurs moyennes de PAD n'avait pas de différence statistiquement significative dans toutes les tranches d'âges dans les deux sexes. Harrabi et al. [16], dans leur étude incluant 1569 sujets âgés de 13 à 19 ans, avaient trouvé que les garçons de 16, 17 et 18 ans avaient des PAS élevées sans différence statistiquement significatives mais les différences statistiquement significatives étaient remarquées chez les filles de 13 et 14 ans concernant la PAD. Dans son étude chez les enfants, Forrester et al. [17] avaient rapporté une corrélation positive entre la PAS et l'âge chez les garçons et négative chez les filles. Cette corrélation négative trouvée entre la PAS et l'âge chez les filles pourrait être expliquée par les modifications hormonales liées à la puberté qui commencent plus tôt chez les filles que chez les garçons. Se référant à la littérature, la PA augmente avec la croissance en âge plus chez les garçons suite à l'augmentation de la masse musculaire pendant la puberté [18-20].

Notre étude a montré que la PAS était en corrélation significative avec le poids, la taille, l'IMC, le tour de taille et la FC dans les deux sexes. Ce constat est similaire à celui faite par l'étude de Harrabi et al. [16] qui rapportait que la PAS était en corrélation positive avec la taille (garçons: r = 0,33; p < 0,0001; filles: r = 0,08; p = 0,02), le poids (garçons: r = 0,47, p < 0,0001; filles: r = 0,35; p < 0,0001) et l'âge (r = 0,12; p < 0,0001). Quant à la PAD dans notre étude, les corrélations significatives positives étaient retrouvées avec le poids (r = 0,093; p = 0,003) et l'IMC (r = 0,079; p = 0,012) seulement chez les filles, alors que la FC était en corrélation significative positive chez les garçons (r = 0,168; p < 0,0001) mais non chez les filles (r = 0,12, p < 0,0001) [16]. Dans une étude similaire chez les adolescents réalisée par Sinaiko et al. [21], une corrélation a été trouvée entre le poids et la PAS chez les garçons (r = 0,167, p < 0,0001) et les filles (r = 0,112, p < 0,0001). L'effet de la taille et du poids sur la PA a déjà été démontré dans plusieurs études transversales antérieures sur les enfants concluant en une forte corrélation positive [22,23]. L'insuffisance de déclaration des naissances à l'état civil dans plusieurs pays en développement, conséquente au recours aux poids de naissance déclarés auprès des parents ou tuteurs, serait un biais dans la réalisation des résultats statistiquement comparables.

Conclusion

Malgré les faiblesses potentielles de la présente étude dans sa conception transversale et les mesures de la PA le même jour, les données pourraient aider les responsables de la santé à adopter une stratégie nationale de prévention de l'hypertension artérielle dans notre population.

Adverse Intrauterine Environment and Cardiac miRNA Expression

Placental insufficiency, high altitude pregnancies, maternal obesity/diabetes, maternal undernutrition and stress can result in a poor setting for growth of the developing fetus. These adverse intrauterine environments result in physiological changes to the developing heart that impact how the heart will function in postnatal life. The intrauterine environment plays a key role in the complex interplay between genes and the epigenetic mechanisms that regulate their expression. In this review we describe how an adverse intrauterine environment can influence the expression of miRNAs (a sub-set of non-coding RNAs) and how these changes may impact heart development. Potential consequences of altered miRNA expression in the fetal heart include; Hypoxia inducible factor (HIF) activation, dysregulation of angiogenesis, mitochondrial abnormalities and altered glucose and fatty acid transport/metabolism. It is important to understand how miRNAs are altered in these adverse environments to identify key pathways that can be targeted using miRNA mimics or inhibitors to condition an improved developmental response.

Distribution of Glycated Haemoglobin According to Early-Life and Contemporary Characteristics in Adolescents and Adults without Diabetes: The 1982 and 1993 Pelotas Birth Cohorts

Aim

Glycated haemoglobin (HbA_1c), a marker of glucose control in individuals with diabetes mellitus, is also related with the incidence of cardiometabolic risk in populations free of disease. The aim of this study was to describe the distribution of HbA_1c levels according to early-life and contemporary factors in adolescents and adults without diabetes mellitus.

Methods

HbA_1c was measured in adults aged 30 years and adolescents aged 18 years who are participants in the 1982 and 1993 Pelotas Birth Cohorts, respectively. Bivariate and multivariate analyses were performed to describe the HbA_1c mean values according to early-life and contemporary characteristics collected prospectively since birth.

Results

The distribution of the HbA_1c was approximately normal in both cohorts, with a mean (SD) 5.10% (0.43) in the 1982 cohort, and 4.89% (0.50) in the 1993 cohort. HbA_1c mean levels were significantly higher in individuals self-reported as black/brown skin color compared to those self-reported as white in both cohorts. Parental history of diabetes was associated with higher HbA_1c mean in adults, while stunting at one year old presented an inverse relation with the outcome in adolescents. No other early and contemporary factors were associated with HbA_1c levels in adults or adolescents.

Conclusions

We found a consistent relationship between HbA_1c and skin color in both cohorts. Further research is needed to understand the role of genomic ancestry on levels of HbA_1c concentrations which may inform policies and preventive actions for diabetes mellitus and cardiometabolic risk.

The metabolic syndrome: an emerging risk state for cardiovascular disease

The common clustering of glucose intolerance, insulin resistance, abdominal adiposity, elevated blood pressure, and low HDL cholesterol is referred to as metabolic syndrome. Individuals with this syndrome have an increased risk of developing cardiovascular disease (CVD). The World Health Organisation and the National Cholesterol Education Programme’s Adult Treatment Panel III (NCEP-ATP III) have outlined specific diagnostic criteria for the diagnosis of the metabolic syndrome to help in the Identification of this syndrome in clinical practice. While the WHO criteria were specifically developed for use in research, the NCEP criteria are useful in clinical diagnosis of the metabolic syndrome. The metabolic syndrome is amenable to lifestyle modifications such as increased physical activity, weight loss, and possibly intake of low-glycemic foods. Drug therapy may be used to treat individual components of the syndrome such as elevated blood pressure and dyslipidemia. To control elevated glucose levels (when there is failure of lifestyle modification), medications such as metformin, thiazolidinedione derivatives and alpha glucosidase inhibitors may be used.

Programming of Essential Hypertension: What Pediatric Cardiologists Need to Know

Hypertension is recognized as one of the major contributing factors to cardiovascular disease, but its etiology remains incompletely understood. Known genetic and environmental influences can only explain a small part of the variability in cardiovascular disease risk. The missing heritability is currently one of the most important challenges in blood pressure and hypertension genetics. Recently, some promising approaches have emerged that move beyond the DNA sequence and focus on identification of blood pressure genes regulated by epigenetic mechanisms such as DNA methylation, histone modification and microRNAs. This review summarizes information on gene-environmental interactions that lead toward the developmental programming of hypertension with specific reference to epigenetics and provides pediatricians and pediatric cardiologists with a more complete understanding of its pathogenesis.

The Presence of Risk Factors for Type 2 Diabetes Mellitus in Underserved Preschool Children

This study identified risk factors (ie, high-risk racial/ethnic group, overweight/obesity, elevated blood pressure, elevated casual blood glucose, and the presence of acanthosis nigricans) for the development of type 2 diabetes mellitus (T2DM) in underserved children with or without a family history of diabetes during annual preschool health screenings. Early identification of risk factors for the development of T2DM will allow for effective interventions to be implemented, thus, improving the long-term health-related quality of life of at-risk children.

Sex differences in the developmental origins of cardiovascular disease

The Developmental Origins of Health and Disease (DOHaD) proposes that adverse events during early life program an increased risk for cardiovascular disease. Experimental models provide proof of concept but also indicate that insults during early life program sex differences in adult blood pressure and cardiovascular risk. This review will highlight the potential mechanisms that contribute to the etiology of sex differences in the developmental programming of cardiovascular disease.

Contextual risk factors for low birth weight: a multilevel analysis

BACKGROUND

Low birth weight (LBW) remains to be a leading cause of neonatal death and a major contributor to infant and under-five mortality. Its prevalence has not declined in the last decade in sub-Saharan Africa (SSA) and Asia. Some individual level factors have been identified as risk factors for LBW but knowledge is limited on contextual risk factors for LBW especially in SSA.

METHODS

Contextual risk factors for LBW in Ghana were identified by performing multivariable multilevel logistic regression analysis of 6,900 mothers dwelling in 412 communities that participated in the 2003 and 2008 Demographic and Health Surveys in Ghana.

RESULTS

Contextual-level factors were significantly associated with LBW: Being a rural dweller increased the likelihood of having a LBW infant by 43% (OR 1.43; 95% CI 1.01-2.01; P-value <0.05) while living in poverty-concentrated communities increased the risk of having a LBW infant twofold (OR 2.16; 95% CI 1.29-3.61; P-value <0.01). In neighbourhoods with a high coverage of safe water supply the odds of having a LBW infant reduced by 28% (OR 0.74; 95% CI 0.57-0.96; P-value <0.05).

CONCLUSION

This study showed contextual risk factors to have independent effects on the prevalence of LBW infants. Being a rural dweller, living in a community with a high concentration of poverty and a low coverage of safe water supply were found to increase the prevalence of LBW infants. Implementing appropriate community-based intervention programmes will likely reduce the occurrence of LBW infants.

Socio-economic position and cardiovascular risk in rural Indian adolescents: evidence from the Andhra Pradesh children and parents study (APCAPS)

Objectives

This study examined association between socio-economic position and cardiovascular risk factors in adolescents to investigate whether childhood socio-economic position is a risk factor for future cardiovascular disease, independently of adult behaviours.

Study design and methods

Participants (n = 1128, 46% girls, aged 13–18 years) were members of a birth cohort (Andhra Pradesh Children and Parents Study or APCAPS) established to investigate long-term effects of a pregnancy and childhood nutritional supplementation trial conducted in 29 villages near Hyderabad in South India. Cross-sectional associations between socio-economic position and cardiovascular risk factors were examined using linear regression models.

Results

The mean BMI was 16.7 kg/m² for boys and 17.8 kg/m² for girls. Socio-economic position was positively associated with fat mass index (0.15 kg/m²; 95% CI: 0.05–0.25) and inversely associated with central-peripheral skinfold ratio (−0.04; 95% CI: −0.06 to −0.01) and, in boys, fasting triglycerides (−0.05; 95% CI: −0.09 to −0.01). Association of socio-economic position with other risk factors (blood pressure, arterial stiffness, fasting glucose, insulin and cholesterol) was weak and inconsistent, and did not persist after adjustment for potential confounders, including age, sex, pubertal stage, height, adiposity and nutrition supplementation.

Conclusions

The study thus showed that lower socio-economic position may be associated with greater central adiposity and higher triglyceride levels in these settings. Socio-economic gradient in cardiovascular risk may strengthen in future with later economic and lifestyle changes. Cardiovascular disease prevention strategies should therefore focus on the youth from the low income group.

Glucose metabolism in adult survivors of severe acute malnutrition

CONTEXT AND OBJECTIVES

The clinical syndromes of severe acute malnutrition may have early life origins because children with marasmus have lower birth weight than those with kwashiorkor. We hypothesized that resultant metabolic effects may persist into adulthood. We investigated whether marasmus survivors (MS) are more insulin resistant and glucose intolerant than kwashiorkor survivors (KS).

RESEARCH DESIGN AND SETTING

This was a case-control study in Jamaican adults.

SUBJECTS

We performed oral glucose tolerance tests on 191 adults (aged 17-50 y; 52% male; body mass index 24.2 ± 5.5 kg/m(2)). There were 43 MS; 38 KS; 70 age-, sex-, and body mass index-matched community controls; and 40 age- and birth weight-matched controls.

MEASUREMENTS

We measured insulin sensitivity with the whole-body insulin sensitivity index, and β-cell function with the insulinogenic index and the oral disposition index.

RESULTS

Fasting glucose was comparable across groups, but glucose intolerance was significantly more common in MS (19%) than in KS (3%), community controls (11%), and birth weight-matched controls (10%). The whole-body insulin sensitivity index was lower in MS than KS (P = .06) but similar between MS and controls. The insulinogenic index and oral disposition index were lower in MS compared with all three groups (P < .01).

CONCLUSIONS

Marasmus survivors tend to be less insulin sensitive, but have significantly lower insulin secretion and are more glucose intolerant compared with kwashiorkor survivors and controls. This suggests that poor nutrition in early life causes β-cell dysfunction, which may predispose to the development of diabetes.

The impact of malaria in pregnancy on changes in blood pressure in children during their first year of life

We established a maternal birth cohort in Ibadan, Nigeria, where malaria is hyperendemic, to assess how intrauterine exposure to malaria affected infant blood pressure (BP) development. In a local maternity hospital, healthy pregnant women had regular blood films for malaria parasites from booking to delivery. Growth and BP were measured on 318 babies, all followed from birth to 3 and 12 months. Main outcomes were standardized measures of anthropometry and change in BP to 1 year. Babies exposed to maternal malaria were globally smaller at birth, and boys remained smaller at 3 months and 1 year. Change in systolic BP (SBP) during the year was greater in boys than in girls (20.9 versus 15.7 mm Hg; P=0.002) but greater in girls exposed to maternal malaria (18.7 versus 12.7 mm Hg; 95% confidence interval, 1-11 mm Hg; P=0.02). Eleven percent of boys (greater than twice than expected) had a SBP ≥95th percentile (hypertensive, US criteria), of whom 68% had maternal malaria exposure. On regression analysis (β coefficients, mm Hg), sex (boys>girls; β=4.4; 95% confidence interval, 1.1-7.7; P=0.01), maternal malaria exposure (3.64; 0.3-6.9; P=0.03), and weight change (2.4; 0.98-3.8/1 standard deviation score; P=0.001) all independently increased SBP change to 1 year, whereas increase in length decreased SBP (-1.98; -3.6 to -0.40). In conclusion, malaria-exposed boys had excess hypertension, whereas malaria-exposed girls a greater increase in SBP. Intrauterine exposure to malaria had sex-dependent effects on BP, independent of infant growth. Because infant-child-adult BP tracking is powerful, a malarial effect may contribute to the African burden of hypertension.

Relationship between lipid and lipoprotein metabolism in trimesters of pregnancy in Nigerian women: Is pregnancy a risk factor?

BACKGROUND

Changes in lipid metabolism have been shown to occur during pregnancy, to ensure a continuous supply of nutrients to the growing fetus, despite intermittent maternal food intake. Abnormal lipid metabolism has also been linked to atherosclerosis.

OBJECTIVE

To investigate the effect of pregnancy on the lipid profile and possible predisposition of pregnant Nigerian women to atherosclerosis.

SETTINGS AND DESIGN

Serum lipid and lipoprotein levels of 60 apparently healthy pregnant women aged between 25 and 45 years, attending the antenatal clinic of the U.N.T.H, Enugu and 60 apparently healthy non-pregnant, age-matched females (controls) were estimated. The test samples were collected from each subject at each of the trimesters.

MATERIALS AND METHODS

Total cholesterol (TC), high-density lipoprotein (HDL) and triglyceride (TG) were analyzed using enzymatic/spectrophotometric methods while low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) were calculated using Friedewald's formula.

STATISTICAL ANALYSIS USED

The data obtained were analyzed with Students' t-test and Pearson's Product Moment Correlation, using graph pad prism software program and results expressed as mean ± SD. The level of significance was determined at 95% confidence level.

RESULTS AND CONCLUSION

The serum lipid levels were significantly higher (P<0.05) in all the trimesters of the pregnant women than in the controls. There was a steady increase in the serum lipid levels with increasing gestational age. A significant positive correlation (P<0.05) was observed between the lipid fractions and the different trimesters of pregnancy. TC/HDL was decreased significantly (P<0.05) in pregnant women, with increasing gestational age. Cardiac risk factor, however, decreased with gestational age, signifying possible protection from atherosclerosis. A comparison of two age groups of pregnant women (25-34 years and 35-45 years) showed no significant differences (P>0.05) in all the lipid fractions studied, suggesting no possible age-related effect on lipid metabolism in the women in their first trimester. Even with significant increase in plasma lipid during pregnancy, normal pregnancy in Nigerian women does not appear to increase the risk.

Low nephron number and its clinical consequences

Epidemiologic studies now strongly support the hypothesis, proposed over two decades ago, that developmental programming of the kidney impacts an individual's risk for hypertension and renal disease in later life. Low birth weight is the strongest current clinical surrogate marker for an adverse intrauterine environment and, based on animal and human studies, is associated with a low nephron number. Other clinical correlates of low nephron number include female gender, short adult stature, small kidney size, and prematurity. Low nephron number in Caucasian and Australian Aboriginal subjects has been shown to be associated with higher blood pressures, and, conversely, hypertension is less prevalent in individuals with higher nephron numbers. In addition to nephron number, other programmed factors associated with the increased risk of hypertension include salt sensitivity, altered expression of renal sodium transporters, altered vascular reactivity, and sympathetic nervous system overactivity. Glomerular volume is universally found to vary inversely with nephron number, suggesting a degree of compensatory hypertrophy and hyperfunction in the setting of a low nephron number. This adaptation may become overwhelmed in the setting of superimposed renal insults, e.g. diabetes mellitus or rapid catch-up growth, leading to the vicious cycle of on-going hyperfiltration, proteinuria, nephron loss and progressive renal functional decline. Many millions of babies are born with low birth weight every year, and hypertension and renal disease prevalences are increasing around the globe. At present, little can be done clinically to augment nephron number; therefore adequate prenatal care and careful postnatal nutrition are crucial to optimize an individual's nephron number during development and potentially to stem the tide of the growing cardiovascular and renal disease epidemics worldwide.

Influence of maternal nutritional status on vascular function in the offspring

Suboptimal maternal nutritional status has been implicated in the development of cardiovascular risk in the child. Initially inferred from studies of low-birthweight children, investigations in cohorts of women subjected to famine provide direct evidence for an independent influence of the mother's diet on the cardiovascular health of her child. Animal studies from rodents and sheep have shown associations between maternal undernutrition and raised blood pressure, as well as abnormalities in resistance artery function, particularly in endothelium-dependent responses. Early life exposure to the influences of maternal over nutritional states, e.g. obesity and excessive gestational weight gain, has also been associated with markers of cardiovascular risk in man, and animal models have shown raised blood pressure and endothelial dysfunction in offspring of diet-induced obese dams. Increased sympathetic tone is commonly associated with hypertension in animal models of both under nutritional and over nutritional states. This and several other similarities may indicate commonality of mechanism and could reflect supranormal nutritional status in postnatal life in both conditions.

Review and hypothesis: syndromes with severe intrauterine growth restriction and very short stature--are they related to the epigenetic mechanism(s) of fetal survival involved in the developmental origins of adult health and disease?

Diagnosing the specific type of severe intrauterine growth restriction (IUGR) that also has post-birth growth restriction is often difficult. Eight relatively common syndromes are discussed identifying their unique distinguishing features, overlapping features, and those features common to all eight syndromes. Many of these signs take a few years to develop and the lifetime natural history of the disorders has not yet been completely clarified. The theory behind developmental origins of adult health and disease suggests that there are mammalian epigenetic fetal survival mechanisms that downregulate fetal growth, both in order for the fetus to survive until birth and to prepare it for a restricted extra-uterine environment, and that these mechanisms have long lasting effects on the adult health of the individual. Silver-Russell syndrome phenotype has recently been recognized to be related to imprinting/methylation defects. Perhaps all eight syndromes, including those with single gene mutation origin, involve the mammalian mechanism(s) of fetal survival downsizing. Insights into those mechanisms should provide avenues to understanding the natural history, the heterogeneity and possible therapy not only for these eight syndromes, but for the common adult diseases with which IUGR is associated.

Size at birth is associated with blood pressure but not insulin resistance in 6–8 year old children in rural Nepal

Earlier, we reported that antenatal micronutrient supplementation reduced the risk of metabolic syndrome and microalbuminuria among offspring at 6–8 years of age in rural Nepal. In the same birth cohort, we examined associations of size at birth (weight, length and ponderal index), and gestational age, with cardiometabolic risk factors in childhood across all antenatal micronutrient interventions. There was an inverse association between birth weight and systolic blood pressure (SBP,β= −1.20 mm Hg/kg; 95% confidence interval (CI): −1.93, −0.46) and diastolic blood pressure (DBP,β= −1.24 mm Hg/kg; 95% CI: −2.00, −0.49). Current child body mass index was positively associated with SBP but not with DBP. Birth weight was unassociated with insulin resistance, but each kilogram of increase was associated with a reduced risk of high triglycerides (odds ratio (OR) = 0.64/kg; 95% CI: 0.41, 0.97) and an increased risk of high waist circumference (OR = 3.16/kg; 95% CI: 2.47, 4.41). In this rural Nepalese population of children 6–8 years of age with a high prevalence of undernutrition, size at birth was inversely associated with blood pressure and triglycerides and positively associated with waist circumference.

The clinical importance of nephron mass

Abundant evidence supports the association between low birth weight (LBW) and renal dysfunction in humans. Anatomic measurements of infants, children, and adults show significant inverse correlation between LBW and nephron number. Nephron numbers are also lower in individuals with hypertension compared with normotension among white and Australian Aboriginal populations. The relationship between nephron number and hypertension among black individuals is still unclear, although the high incidence of LBW predicts low nephron number in this population as well. LBW, a surrogate for low nephron number, also associates with increasing BP from childhood to adulthood and increasing risk for chronic kidney disease in later life. Because nephron numbers can be counted only postmortem, surrogate markers such as birth weight, prematurity, adult height, reduced renal size, and glomerulomegaly are potentially useful for risk stratification, for example, during living-donor assessment. Because early postnatal growth also affects subsequent risk for higher BP or reduced renal function, postnatal nutrition, a potentially modifiable factor, in addition to intrauterine effects, has significant influence on long-term cardiovascular and renal health.

Perfil lipídico na adolescência: efeito de exposições intra-uterinas

Avaliou-se o efeito do retardo de crescimento intra-uterino e de fatores de risco para o retardo de crescimento intra-uterino sobre o perfil lipídico em adolescentes pertencentes ao estudo de coorte de nascimentos de 1982 de Pelotas, Rio Grande do Sul, Brasil. Em 2000, os participantes do sexo masculino foram identificados no alistamento militar; 79% (n = 2.250) foram entrevistados e 2.089 doaram amostra de sangue. No presente estudo, as variáveis dependentes foram o colesterol total e suas frações (VLDL, LDL, HDL), colesterol não-HDL, razão LDL/HDL e triglicerídeos. As exposições estudadas foram o retardo de crescimento intra-uterino, o índice de massa corporal (IMC) materno pré-gestacional e o tabagismo materno durante a gravidez. Após ajuste para fatores de confusão, o colesterol total, LDL e não-HDL foram maiores entre os adolescentes cujo IMC materno pré-gestacional estava no terceiro e quarto quartil. No entanto, tais associações desapareceram após controle para dieta, escolaridade e IMC do adolescente. O retardo de crescimento intra-uterino e o tabagismo materno na gravidez não foram associados com o perfil lipídico aos 18 anos de idade.

Role of the kidney in the prenatal and early postnatal programming of hypertension

Epidemiologic studies from several different populations have demonstrated that prenatal insults, which adversely affect fetal growth, result in an increased incidence of hypertension when the offspring reaches adulthood. It is now becoming evident that low-birth-weight infants are also at increased risk for chronic kidney disease. To determine how prenatal insults result in hypertension and chronic kidney disease, investigators have used animal models that mimic the adverse events that occur in pregnant women, such as dietary protein or total caloric deprivation, uteroplacental insufficiency, and prenatal administration of glucocorticoids. This review examines the role of the kidney in generating and maintaining an increase in blood pressure in these animal models. This review also discusses how early postnatal adverse events may have repercussions in later life. Causes for the increase in blood pressure by perinatal insults are likely multifactorial and involve a reduction in nephron number, dysregulation of the systemic and intrarenal renin-angiotensin system, increased renal sympathetic nerve activity, and increased tubular sodium transport. Understanding the mechanism for the increase in blood pressure and renal injury resulting from prenatal insults may lead to therapies that prevent hypertension and the development of chronic kidney and cardiovascular disease.

Parental and perinatal factors affecting childhood anthropometry of very-low-birth-weight premature infants: a population-based survey

BACKGROUND

The perinatal-neonatal course of very-low-birth-weight (VLBW) infants might affect their childhood growth. We evaluated the effect of parental anthropometry and perinatal and neonatal morbidity of VLBW neonates on their childhood growth.

METHODS

We obtained parental anthropometry, height and weight at age 6-10.5 years of 334 children born as VLBW infants. Parental, perinatal and neonatal data of these children were tested for association with childhood anthropometry.

RESULTS

(1) Maternal and paternal weight standard deviation score (SDS) and discharge weight (DW) SDS were associated with childhood weight SDS (R(2)= 0.111, p < 0.00001); (2) Maternal and paternal height SDS, corrected gestational age (GA) at discharge, maternal assisted reproduction and SGA status were associated with childhood height SDS (R(2)= 0.208, p < 0.00001); (3) paternal weight SDS, DW SDS and surfactant therapy were associated with childhood body mass index (BMI) SDS (R(2)= 0.096, p < 0.00001). 31.1% of VLBW infants had DW SDS < -1.88, and are to be considered small for gestational age ('SGA'). One quarter of these infants did not catch up by age 6-10.5 years.

CONCLUSION

Childhood anthropometry of VLBW infants depends on parental anthropometry, postnatal respiratory morbidity and growth parameters at birth and at discharge. Almost one-third of VLBW premature infants had growth restriction at discharge from neonatal intensive care unit (NICU), a quarter of whom did not catch up by age 6-10.5 years.

Blood pressure levels in childhood: probing the relative importance of birth weight and current size

Several studies have reported data supporting the idea that an impaired intrauterine environment that deprives the fetus of optimal nutrient delivery results in the predisposition of the fetus to experience cardiovascular and metabolic dysfunction in later life. However, contradictory data still exist. Our purpose was to investigate the effects of both birth weight and weight gain on the risk for high blood pressure levels in 6- to 10-year-old children. This cross-sectional study included 739 children divided into quartiles of birth weight. The mean values of both systolic and diastolic pressure were significantly different between quartiles of birth weight, with increasing blood pressure values as the birth weight decreased (P<0.001). Covariance analysis adjusting for gender, prematurity, and body mass index (BMI) showed that both systolic and diastolic pressure remained greater in the lowest than in the highest birth weight quartile. Separating those with low and normal birth weight demonstrated that the risk of childhood hypertension was significantly higher among children with low birth weight and current obesity (odds ratio [OR]: 5.0, confidence interval [CI]: 3.3 to 16.1; P=0.023). The inverse association between birth weight and blood pressure levels appears to be programmed during fetal life, while weight gain during childhood adds to this risk.

Gross placental measures and childhood growth

OBJECTIVES

We hypothesised that the gross placental measures would be positively associated with childhood growth.

METHODS

We analysed data on 23,967 mother-infant pairs enrolled in the Collaborative Perinatal Project. In race-stratified regression models, the main outcomes were birthweight and z-score body-mass index (BMI) at ages 4 and 7.

RESULTS

Some placental measures were significantly associated with z-score BMI at age 7: in Blacks, placental weight (beta = 0.0004/g; 95%CI: 0.0001, 0.0008), chorionic plate area (beta = 0.0007; 95%CI: 0.0001, 0.0012) and largest diameter (beta = 0.013; 95%CI: 0.004, 0.026); and in Whites placental weight (beta = 0.0004/g; 95%CI: 0.0001, 0.0003) and largest diameter (Model 3: beta = 0.020; 95%CI: 0.007, 0.032). Tested as group, placental measures significantly predicted z-score BMI at age 7 (all p values < 0.005).

CONCLUSIONS

Placental structure independently predicts birthweight and childhood growth. Strategies to improve placental structure might favourably influence birthweight and childhood development.

Breast-feeding history and overweight in 11 to 13-year-old children in Iran

BACKGROUND

The relationship between breast-feeding history and risk of overweight in pre-adolescent children was investigated.

METHODS

Children's breast-feeding history and demographics were obtained in interviewer-administered questionnaires of a multistage cluster sample survey of 800 parents of children aged 11-13 years living in Yazd, Iran. Height and weight were measured in the children. Overweight was defined as body mass index >/=90th age- and sex-specific percentile of the 2000 Centers for Disease Control reference values.

RESULTS

One hundred and four (13.0%) of 800 children were overweight. A total of 783 (97.9%) of the children had been breast fed. There was a markedly lower overweight prevalence among breast-fed than non breast-fed children. Controlling for age and sex, children breast fed for at least 24 months were substantially less likely to be overweight than children breast fed for less than 12 months (OR 0.56, 95% CI 0.31-0.9). A longer overall duration and duration of exclusive breast-feeding were associated significantly with the decreasing prevalence of overweight.

CONCLUSION

This sample of Iranian children shows high rates of overweight at young ages but also high rates of breast-feeding. The duration of breast-feeding is inversely related with the prevalence of overweight in pre-adolescent children.

HbA(1c) levels in non-diabetic Dutch children aged 8-9 years: the PIAMA birth cohort study

AIM

Glycated haemoglobin (HbA(1c)) is considered the best index of glycaemic control in established diabetes. It may also be useful in the diagnosis of diabetes and as a screening tool. Little is known about the distribution of HbA(1c) in healthy children and its predictors. The aim of this study is to describe the distribution of HbA(1c) in non-diabetic Dutch children aged 8-9 years and to investigate potential associations of HbA(1c) in this group.

METHODS

HbA(1c) was measured in 788 non-diabetic children aged 8-9 years participating in the PIAMA birth cohort study. Data on parents and children were collected prospectively by questionnaires. Weight, height and waist and hip circumference of the children were measured when blood samples were taken.

RESULTS

Mean (SD) HbA(1c) was 4.9 +/- 0.33%, range 3.5-6.0%. HbA(1c) was significantly higher in boys (4.9 +/- 0.31 vs. 4.9 +/- 0.33%) and in children of mothers with gestational diabetes (5.0 +/- 0.37 vs. 4.9 +/- 0.32%). We found a significant inverse association between HbA(1c) and haemoglobin (regression coefficient: -0.169 (95% CI -0.221 to -0.118), P < 0.001). HbA(1c) was not significantly associated with age, body mass index, waist circumference, parental diabetes or maternal body mass index.

CONCLUSIONS

We found no significant relation between known risk factors for Type 2 diabetes and HbA(1c) at age 8-9 years. Moreover, there was a significant inverse association between haemoglobin and HbA(1c). These results suggest that HbA(1c) may not only reflect the preceding blood glucose levels, but seems to be determined by other factors as well.

Model Averaging Methods for Weight Trimming

In sample surveys where sampled units have unequal probabilities of inclusion, associations between the inclusion probabilities and the statistic of interest can induce bias. Weights equal to the inverse of the probability of inclusion are often used to counteract this bias. Highly disproportional sample designs have highly variable weights, which can introduce undesirable variability in statistics such as the population mean or linear regression estimates. Weight trimming reduces large weights to a fixed maximum value, reducing variability but introducing bias. Most standard approaches are ad-hoc in that they do not use the data to optimize bias-variance tradeoffs. This manuscript develops variable selection models, termed "weight pooling" models, that extend weight trimming procedures in a Bayesian model averaging framework to produce "data driven" weight trimming estimators. We develop robust yet efficient models that approximate fully-weighted estimators when bias correction is of greatest importance, and approximate unweighted estimators when variance reduction is critical.

Mechanisms underlying developmental programming of elevated blood pressure and vascular dysfunction: evidence from human studies and experimental animal models

Cardiovascular-related diseases are the leading cause of death in the world in both men and women. In addition to the environmental and genetic factors, early life conditions are now also considered important contributing elements to these pathologies. The concept of 'fetal' or 'developmental' origins of adult diseases has received increased recognition over the last decade, yet the mechanism by which altered perinatal environment can lead to dysfunction mostly apparent in the adult are incompletely understood. This review will focus on the mechanisms and pathways that epidemiological studies and experimental models have revealed underlying the adult cardiovascular phenotype dictated by the perinatal experience, as well as the probable key causal or triggering elements. Programmed elevated blood pressure in the adult human or animal is characterized by vascular dysfunction and microvascular rarefaction. Developmental mechanisms that have been more extensively studied include glucocorticoid exposure, the role of the kidneys and the renin-angiotensin system. Other pathophysiological pathways have been explored, such as the role of the brain and the sympathetic nervous system, oxidative stress and epigenetic changes. As with many complex diseases, a unifying hypothesis linking the perinatal environment to elevated blood pressure and vascular dysfunction in later life cannot be presumed, and a better understanding of those mechanisms is critical before clinical trials of preventive or 'deprogramming' measures can be designed.

Fetal growth and childhood cholesterol levels in the United States

Research has linked fetal environment to subsequent adult disease. This study examines the extent to which infants born small-for-gestational age (SGA) were at risk for high cholesterol levels in early childhood (ages 4-6 years). Data were obtained from 1727 children aged 4-6 years who participated in the cross-sectional third US National Health and Nutrition Examination Survey and had both birth certificates and blood cholesterol information. The odds of having moderately elevated (170-199 mg/dL) or high (> or =200 mg/dL) serum total cholesterol after being born SGA were determined after controlling for sex, race/ethnicity, education of household head, saturated fat intake, parental history of high cholesterol and overweight status. Approximately 11% of participants were SGA. Proportions of children with moderately elevated and high cholesterol levels were approximately 28 and 8%, respectively. SGA children were almost twice as likely (odds ratio 1.97, 95% confidence interval [0.8, 4.8]) to have high cholesterol vs. low cholesterol than non-SGA children, although the result was not statistically significant. Multiple linear regression demonstrated a similar inverse, non-significant relationship between gestation-adjusted birthweight and cholesterol (beta = -2.3, P = 0.33). These data indicate a possible association between reduced fetal growth, represented by birthweight adjusted for gestational age, and increased cholesterol levels in early childhood.

Birth weight correlates differently with cardiovascular risk factors in youth

OBJECTIVE

Childhood obesity has become prevalent, resulting in a greater risk of hypertension, diabetes, and dyslipidemia. However, the relationship between these comorbid conditions and birth weight remains uncertain. We conducted this study to evaluate the relationship between birth weight and cardiovascular risk factors in children and adolescents.

RESEARCH METHODS AND PROCEDURES

In a nationwide survey conducted between 1992 and 2000, all schoolchildren 6 to 18 years old with glucosuria, proteinuria, or microscopic hematuria in repeated urine samples were included and received a physical examination and blood test. Those with gestational age <37 weeks were excluded. We enrolled 81,538 children (51,111 girls and 30,427 boys) and obtained their birth weights from the Taiwan Birth Registry. Obesity and hypertension were defined by age- and sex-specific cut-offs. Diabetes was diagnosed if the fasting glucose was >7 mM.

RESULTS

The risk of obesity was higher for those with birth weights > or =4000 grams [odds ratio (OR), 1.65] and 3543 to 3999 grams (OR, 1.28) and lower for those with birth weights 2601 to 2999 grams (OR, 0.90), using 3000 to 3542 grams as the reference group. An increased risk of diabetes was associated with both higher and lower birth weights, indicating a U-shaped relationship (OR, <2600 grams, 1.607; 2601 to 2999 grams, 1.119; 3543 to 3999 grams, 1.112; > or =4000 grams, 1.661). In the 10- to 12-year-old age group, the risk of hypertension was higher in those with birth weights <2600 grams (OR, 1.20).

DISCUSSION

Low birth weight was associated with childhood diabetes. High birth weight was correlated with childhood obesity and diabetes. Our data indicate different relationships between birth weight and the development of obesity, hypertension, and diabetes in childhood.

Haemoglobin A1c is not a surrogate for glucose and insulin measures for investigating the early life and childhood determinants of insulin resistance and Type 2 diabetes in healthy children. An analysis from the Avon Longitudinal Study of Parents and Children (ALSPAC)

AIMS

Research into early life and childhood determinants of insulin resistance and Type 2 diabetes are complicated by requirements for fasting blood samples and glucose tolerance tests. We investigated haemoglobin A(1c) (HbA(1c)), a marker of glycaemia measured in non-fasting blood, as an alternative.

METHODS

HbA(1c) was measured in 1645 children aged 9-11 years without diabetes from the Avon Longitudinal Study of Parents and Children. Thirty-nine children had two HbA(1c) measurements. Data on parental, child and potential confounding factors were collected prospectively from questionnaires, medical records and direct examination. Data from a shortened 30-min oral glucose tolerance test were available for 431 children at age 8 years. Body composition was measured by dual-energy X-ray absorptiometry.

RESULTS

Mean (sd) HbA(1c) was 4.91(0.29)%. HbA(1c) increased with age and was higher in boys compared with girls, non-white compared with white children, and in children with anaemia. Mean difference between repeated HbA(1c) measurements was 0.01%. HbA(1c) was weakly positively associated with fasting glucose (beta = 0.066%/mmol/l, P = 0.05), but was not associated with 30-min glucose, fasting or 30-min insulin, or homeostasis model assessment-insulin resistance. HbA(1c) was weakly inversely associated with weight sd score (beta =-0.02%/unit, P = 0.004), body mass index sd score (beta = -0.02%/unit, P = 0.002), and total body fat (beta = -0.003%/kg, P = 0.06) and lean mass (beta = -0.011%/kg, P = 0.01), but was not associated with birthweight or breastfeeding.

CONCLUSIONS

HbA(1c) is not a good marker of fasting or post-load glucose and insulin measures in healthy children, and is not a viable alternative to these measures for investigating the determinants of insulin resistance and Type 2 diabetes in children.

Racial disparities in the association between birth weight in the term infant and blood pressure at age 7 years: results from the collaborative perinatal project

BP has been inversely associated with birth weight in studies worldwide, but few studies have included black individuals. The US National Collaborative Perinatal Project followed 58,960 pregnant women and their resultant offspring for 7 yr. In this post hoc analysis, all term white or black children without kidney or heart disease were included (n = 29,710). The effect of birth weight and other risk factors on systolic (SBP) and diastolic BP (DBP) was evaluated at 7 yr. Mean birth weight and body mass index at 7 yr were slightly lower for black compared with white children (birth weight 3.14 +/- 0.48 versus 3.32 +/- 0.46 kg [P < 0.001]; body mass index 15.8 +/- 2.0 versus 16.3 +/- 2.0 [P < 0.001]). Compared with white mothers, black mothers were less likely to smoke (41 versus 52%), were more anemic (23 versus 7%), and were more likely to live in poverty (72 versus 39%). In linear regression, there was significant interaction between race and birth weight in predicting SBP (P = 0.002). In bivariate analysis, birth weight was positively associated with SBP (beta = 0.87) and DBP (beta = 1.14) in black children (P < 0.001) but not associated with either in white children. With maternal poverty, educational level, and anemia during pregnancy added to the model, birth weight remained a significant positive predictor of SBP (beta = 0.89, P < 0.001) in black but not in white children (beta = 0.02, P = 0.17). The association between birth weight and SBP differs between black and white children. The cause of intrauterine growth restriction-associated hypertension seems to be race sensitive; therefore, future studies of racial disparities in the "Barker hypothesis" may help in the understanding of the mechanism of fetal programming of hypertension.

Measuring the full economic costs of diet, physical activity and obesity-related chronic diseases

Most studies that have focused on the costs of obesity have ignored the direct effects of obesity-related patterns of diet and physical activity. This study reviews the full effects of each component--poor dietary and physical activity patterns and obesity--on morbidity, mortality and productivity. The direct healthcare costs are based on a review of the effects of these factors on key diseases and the related medical care costs of each disease. The indirect costs on reduced disability, mortality and sickness during the period of active labour force participation prior to retirement are also examined. A case study is prepared for China to provide some guidance in the utilization of this review for economic analysis of obesity. The case study shows that the indirect costs are often far more important than the direct medical care costs. The Chinese case study found that the indirect effects of obesity and obesity-related dietary and physical activity patterns range between 3.58% and 8.73% of gross national product (GNP) in 2000 and 2025 respectively.

What is the effect of adjusting for more than one measure of current body size on the relation between birthweight and blood pressure?

The statistical validity of the negative associations observed between birthweight and disease in later life has recently been questioned, because these associations might be due, in part, to inappropriate adjustment for current body size, creating a statistical artefact known as the 'reversal paradox'. The aim of this study was to explore the effect of adjusting for more than one measure of current body size on the association between birthweight and disease in later life using simulations and meta-analyses of empirical studies. The simulations examined the relation between birthweight and adult systolic blood pressure before and after adjusting for one, two or three measures of current body size by including current weight and subsequently adding body mass index and height in successive analytical models. Meta-analyses were then performed to compare the effect sizes observed among empirical studies reporting associations between birthweight and blood pressure before and after adjusting for one or two measures of current body size. The meta-analyses confirmed the results of the simulations - both showed that associations between birthweight and blood pressure tend to become increasingly negative following adjustment for current body size, and that this effect is enhanced after adjusting for additional measures of current body size.

Epidemiology of hypertension among a population of school children in Sousse, Tunisia

BACKGROUND

Pediatric hypertension is a field of increasing interest and importance. Early identification of children at risk for hypertension is important to prevent the serious, long-term complications associated with the condition. In Tunisia, there are no data available on the cardiovascular disease risk profile, such as hypertension, in the population of children.

OBJECTIVE

To establish the prevalence of hypertension, the percentile distribution of blood pressure and the inter-relationships between hypertension and other cardiovascular disease risk factors among school children.

METHODS

An epidemiological survey was conducted based on a representative sample of 1569 urban school children in Sousse, Tunisia.

RESULTS

The prevalence of arterial hypertension was 9.6%, with no significant difference between boys (9.2%) and girls (9.9%). The prevalence of systolic and diastolic hypertension was 6.4% and 4.5%, respectively. In both boys and girls, systolic pressure had a highly significant positive correlation with height (boys: r=0.33, P<0.001; girls: r=0.08, P=0.02), weight (boys: r=0.47, P < or = 0.001; girls: r=0.35, P<0.001) and triglyceride concentrations (boys: r=0.13, P<0.001; girls: r=0.10, P=0.006). Among boys, a positive correlation was found between systolic blood pressure and age (r=0.12, P=0.001) and, among girls, a negative correlation was found (r=-0.12, P=0.001).

CONCLUSION

This information will be used to help launch a regional program of heart health promotion in schools.

The relation between birth weight and insulin resistance in Korean adolescents

Low birth weight is associated with insulin resistance and type 2 diabetes in adults. The fetal programming hypothesis has shown that insulin resistance and its associated metabolic disturbances result from a poor gestational environment, for which low birth weight is a surrogate. An at-home questionnaire survey was performed on 660 middle school students (12-15 years) in Seoul, Korea, and 152 cases were randomly selected based on their birth weight. Subjects were divided into three groups according to birth weight. We recorded their birth weight and measured their current anthropometric data, blood pressure, lipid profile, HOMA-IR, and HOMA-beta, and compared these parameters among the groups. The relation of birth weight to physiological characteristics in adolescence was examined. Systolic blood pressure, lipid profiles, and fasting plasma glucose, HOMA-beta were not significantly different among the groups, but diastolic blood pressure was lower in the third tertile. Insulin, C-peptide, and HOMA-IR were higher in the lower birth weight tertile. After adjustment for confounding factors, birth weight was inversely related to diastolic blood pressure, insulin, C-peptide, and HOMA-IR. We conclude that low birth weight may predict the risk of the insulin resistance and its progression over age, and that adequate gestational nutrition is therefore necessary to prevent low birth weight.

Low birth weight, nephron number, and kidney disease

More and more evidence is emerging that highlights the far-reaching consequences of prenatal (intrauterine) programming on organ function and adult disease. In humans, low birth weight (LBW) occurs more frequently in disadvantaged communities among whom there is often a disproportionately high incidence of adult cardiovascular disease, hypertension, diabetes mellitus, and kidney disease. Indeed, many epidemiologic studies have found an inverse association between LBW and higher blood pressures in infancy and childhood, and overt hypertension in adulthood. Multiple animal models have demonstrated the association of LBW with later hypertension, mediated, at least in part, by an associated congenital nephron deficit. Although no direct correlation has been shown between nephron number and birth weight in humans with hypertension, nephron numbers were found to be lower in adults with essential hypertension, and glomeruli tend to be larger in humans of lower birth weight. An increase in glomerular size is consistent with hyperfiltration necessitated by a reduction in total filtration surface area, which suggests a congenital nephron deficit. Hyperfiltration manifests clinically as microalbuminuria and accelerated loss of renal function, the prevalence of which are higher among adults who had been of LBW. A kidney with a reduced nephron number has less renal reserve to adapt to dietary excesses or to compensate for renal injury, as is highlighted in the setting of renal transplantation, where smaller kidney to recipient body-weight ratios are associated with poorer outcomes, independent of immunologic factors. Both hypertension and diabetes are leading causes of end-stage renal disease worldwide, and their incidences are increasing, especially in underdeveloped communities. Perinatal programming of these 2 diseases, as well as of nephron number, may therefore have a synergistic impact on the development of hypertension and kidney disease in later life. Existing evidence suggests that birth weight should be used as a surrogate marker for future risk of adult disease. Although the ideal solution to minimize morbidity would be to eradicate LBW, until this panacea is realized, it is imperative to raise awareness of its prognostic implications and to focus special attention toward early modification of risk factors for cardiovascular and renal disease in individuals of LBW.

Birthweight and blood pressure in five European birth cohort studies: an investigation of confounding factors

BACKGROUND

It has been suggested that the association between birthweight and blood pressure has been overstated as a result of publication bias and, within studies, a lack of adjustment for potentially important maternal and socioeconomic confounding factors and 'overadjustment' for current body size. This study investigates the impact of potential confounding variables on the birthweight-blood pressure association in birth cohort studies from different time periods and geographical locations in Europe.

METHODS

Data from five European birth cohort studies (from Finland, the UK, and the Faroe Islands) taking part in the European Birth-Lifecourse-Studies (EURO-BLCS) project were analysed. Birthweight was measured at birth in all cohorts and confounding variable information was collected prospectively at subsequent follow-ups in all cohorts. Regression models were used to assess the unadjusted association between birthweight and blood pressure and then to assess the impact of potential maternal and socioeconomic confounding variables and adjustment for later body size. Analyses were carried out in the same way across all five cohorts.

RESULTS

Birthweight was consistently negatively associated with systolic blood pressure (SBP) across all cohorts. Gestational age and possibly maternal pre-pregnancy weight, but not socioeconomic status, may be important confounding factors of the relationship between birthweight and SBP. The size of the birthweight-SBP association in adulthood may be larger than in childhood before adjustment for current body size, although a cohort effect cannot be ruled out.

CONCLUSION

This study highlights the value of future cross-cohort comparisons in the investigation of the foetal origins of adult disease.