Early Life Growth, Adiposity and Cardiovascular Health in Childhood: The Generation R Study

Cardiovascular disease is a major public health problem worldwide and might originate in early life. Not only fetal life, but also early postnatal life is important for cardiovascular health. Common risk factors for cardiovascular disease, such as blood pressure, lipid levels and obesity track from childhood to adulthood. Both an adverse fetal environment and an affluent postnatal environment seem to adversely affect cardiovascular health from childhood to adulthood. Identifying the risk factors and the sensitive periods in early life and the mechanisms through which early life affects cardiovascular health are important for future preventive strategies to ensure cardiovascular health later in the life course. Therefore, studies presented in this thesis were designed to identify fetal, infant and childhood factors associated with cardiovascular health outcomes in childhood. The research is part of Generation R, a large and longitudinal cohort study on growth, development and health of 10.000 children from Rotterdam. Findings from this thesis suggest that early-life growth and adiposity related factors are associated with cardiac structure and adverse cardiovascular outcomes in children. Future studies should focus on how changes in cardiac structure and cardiovascular outcomes in childhood relate to cardiovascular disease risk in adulthood. Pr

Tracking of structural and functional cardiac measures from infancy into school-age

Objective Cardiac structure and function are important predictors for cardiovascular disease in adults. Not much is known about tracking of cardiac measures, other than left ventricular mass, from early life onwards. We examined whether and to what extent cardiac measures track from infancy into school-age. Methods We performed a population-based prospective cohort study among 1072 children. Aortic root diameter, left atrial diameter, left ventricular mass, relative wall thickness and fractional shortening were measured repeatedly by echocardiography. We explored tracking between infancy (1.5, six and 24 months) and school-age (six and 10 years). Results Of all cardiac measures, aortic root diameter, left atrial diameter and left ventricular mass were significantly correlated between infancy and school-age (r = 0.10-0.42, all p-values < 0.01), with the strongest correlations between 24 months and 10 years. Of the different structures, aortic root diameter showed the strongest correlations. Approximately 30% of children who were in the lowest or highest quartile of a measure at the age of 1.5 months remained in that quartile at the age of 10 years. When analysing the effects of the infant cardiac measures on the same outcomes at 10 years in conditional regression models, we observed ef

Pericardial adipose tissue, cardiac structures, and cardiovascular risk factors in school-age children

Aims We examined the associations of pericardial adipose tissue with cardiac structures and cardiovascular risk factors in children.Methods and results We performed a cross-sectional analysis in a population-based cohort study among 2892 children aged 10 years (2404 normal weight and 488 overweight/obese). Pericardial adipose tissue mass was estimated by magnetic resonance imaging (MRI) and indexed on height 3 . Left ventricular mass (LVM) and left ventricular mass-to-volume ratio (LMVR) were estimated by cardiac MRI. Cardiovascular risk factors included android adipose tissue percentage obtained by Dual-energy X-ray absorptiometry, blood pressure and glucose, insulin, cholesterol, and triglycerides concentrations. Adverse outcomes were defined as values above the 75 percentile. Median pericardial adipose tissue index was 3.6 (95% range 1.6-7.1) among normal weight and 4.7 (95% range 2.0-8.9) among overweight children. A one standard deviation (1 SD) higher pericardial adipose tissue index was associated with higher LMVR [0.06 standard deviation scores, 95% confidence interval (CI) 0.02-0.09], increased odds of high android adipose tissue [odd ratio (OR) 2.08, 95% CI 1.89-2.29], high insulin concentrations (OR 1.17, 95% CI 1.06-1.30), an atherogenic lipid profile (OR 1.22, 95% CI 1.11-1.33), and clustering of cardiovascular risk factors (OR 1.56, 95% CI 1.36-1.79). Pericardial adipose tissue index was not associated with LVM, blood pressure, and glucose concentrations. The associations showed largely the same directions but tended to be weaker among normal weight than among overweight children.Conclusion Pericardial adipose tissue is associated with cardiac adaptations and cardiovascular risk factors already in childhood in both normal weight and overweight children.Developmen

Adjustment for time-invariant and time-varying confounders in ‘unexplained residuals’ models for longitudinal data within a causal framework and associated challenges

‘Unexplained residuals’ models have been used within lifecourse epidemiology to model an exposure measured longitudinally at several time points in relation to a distal outcome. It has been claimed that these models have several advantages, including: the ability to estimate multiple total causal effects in a single model, and additional insight into the effect on the outcome of greater-than-expected increases in the exposure compared to traditional regression methods. We evaluate these properties and prove mathematically how adjustment for confounding variables must be made within this modelling framework. Importantly, we explicitly place unexplained residual models in a causal framework using directed acyclic graphs. This allows for theoretical justification of appropriate confounder adjustment and provides a framework for extending our results to more complex scenarios than those examined in this paper. We also discuss several interpretational issues relating to unexplained residual models within a causal framework. We argue that unexplained residual models offer no additional insights compared to traditional regression methods, and, in fact, are more challenging to implement; moreover, they artificially reduce estimated standard errors. Consequently, we conclude that unexplained residual models, if used, must be implemented with great care

Birth weight, cardiometabolic risk factors and effect modification of physical activity in children and adolescents: pooled data from 12 international studies

Abstract: Objectives: Low and high birth weight is associated with higher levels of cardiometabolic risk factors and adiposity in children and adolescents, and increases the risk of cardiovascular diseases, obesity, and early mortality later in life. Moderate-to-vigorous physical activity (MVPA) is associated with lower cardiometabolic risk factors and may mitigate the detrimental consequences of high or low birth weight. Thus, we examined whether MVPA modified the associations between birth weight and cardiometabolic risk factors in children and adolescents. Methods: We used pooled individual data from 12 cohort- or cross-sectional studies including 9,100 children and adolescents. Birth weight was measured at birth or maternally reported retrospectively. Device-measured physical activity (PA) and cardiometabolic risk factors were measured in childhood or adolescence. We tested for associations between birth weight, MVPA, and cardiometabolic risk factors using multilevel linear regression, including study as a random factor. We tested for interaction between birth weight and MVPA by introducing the interaction term in the models (birth weight x MVPA). Results: Most of the associations between birth weight (kg) and cardiometabolic risk factors were not modified by MVPA (min/day), except between birth weight and waist circumference (cm) in children (p = 0.005) and HDL-cholesterol (mmol/l) in adolescents (p = 0.040). Sensitivity analyses suggested that some of the associations were modified by VPA, i.e., the associations between birth weight and diastolic blood pressure (mmHg) in children (p = 0.009) and LDL- cholesterol (mmol/l) (p = 0.009) and triglycerides (mmol/l) in adolescents (p = 0.028). Conclusion: MVPA appears not to consistently modify the associations between low birth weight and cardiometabolic risk. In contrast, MVPA may mitigate the association between higher birth weight and higher waist circumference in children. MVPA is consistently associated with a lower cardiometabolic risk across the birth weight spectrum. Optimal prenatal growth and subsequent PA are both important in relation to cardiometabolic health in children and adolescents

Associations of Maternal Glycemia in the First Half of Pregnancy With Alterations in Cardiac Structure and Function in Childhood

OBJECTIVE Gestational diabetes mellitus has been associated with offspring cardiac congenital malformations, ventricular hypertrophy, and diastolic dysfunction in large observational cohort studies and experimental animal models. We assessed the associations of maternal random glucose concentrations across the full range with childhood cardiac ventricular structure and function. RESEARCH DESIGN AND METHODS In a population-based prospective cohort among 1,959 women and their offspring, maternal random glucose concentrations were measured at a median 13.1 weeks' gestation (95% range 10.5-16.8 weeks). We obtained offspring cardiac outcomes, relative to body size, through cardiac MRI at 10 years. RESULTS The mean maternal random glucose concentration was 4.4 mmol/L (SD 0.8). The highest quintile of maternal glucose concentrations, compared with the lowest quintile, was associated with a lower childhood left ventricular mass (-0.19 SD score [SDS]; 95% CI -0.31, -0.07) and left ventricular end-diastolic volume (-0.17 SDS; 95% -0.28, -0.05). Also, higher maternal glucose concentrations across the full range per 1 mmol/L increase were associated with a lower childhood left ventricular mass and left ventricular end-diastolic volume (Pvalues <= 0.05). Adjustment for maternal prepregnancy BMI, gestational age, and weight at birth or childhood BMI and blood pressure did not influence the effect estimates. Maternal glucose concentrations were not significantly associated with childhood right ventricular end-diastolic volume or left and right ventricular ejection fraction. CONCLUSIONS Higher maternal random glucose concentrations in the first half of pregnancy are associated with a lower childhood left ventricular mass and left ventricular end-diastolic volume, with the strongest associations for childhood left ventricular mass. These associations were not explained by maternal, birth, or childhood characteristics. Further studies are needed to replicate these findings using repeated maternal glucose measurements throughout pregnancy and offspring cardiac outcomes throughout childhood and adulthood.Developmen

Associations of Fetal and Infant Weight Change With General, Visceral, and Organ Adiposity at School Age

IMPORTANCE Both fetal and infant growth influence obesity later in life. The association of longitudinal fetal and infant growth patterns with organ fat is unknown. OBJECTIVE To examine the associations of fetal and infant weight change with general, visceral, and organ adiposity at school age. DESIGN, SETTING, AND PARTICIPANTS This cohort study was embedded in the Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Pregnant women with a delivery date between April 2002 and January 2006 were eligible to participate. Follow-up measurements were performed for 3205 children. Data analysis of this population was performed from July 26, 2018, to February 7, 2019. EXPOSURES Fetal weight was estimated in the second and third trimester of pregnancy. Infant weight was measured at 6, 12, and 24 months. Fetal and infant weight acceleration or deceleration were defined as a change in standard deviation scores greater than 0.67 between 2 ages. MAIN OUTCOMES AND MEASURES Visceral fat index, pericardial fat index, and liver fat fraction were measured by magnetic resonance imaging. RESULTS The sample consisted of 3205 children (1632 girls [50.9%]; mean [SD] age, 9.8 [0.3] years). Children born small for gestational age had the lowest median body mass index compared with children born appropriate for gestational age and large for gestational age (16.4 [90% range, 14.1-23.6] vs 16.9 [90% range, 14.4-22.8] vs 17.4 [90% range, 14.9-22.7]). Compared with children with normal fetal and infant growth (533 of 2370 [22.5%]), those with fetal weight deceleration followed by infant weight acceleration (263 of 2370 [11.1%]) had the highest visceral fat index (standard deviation scores, 0.18; 95% CI, 0.03-0.33; P = .02) and liver fat fraction (standard deviation scores, 0.34; 95% CI, 0.20-0.48; P < .001). CONCLUSIONS AND RELEVANCE Fetal and infant weight change patterns were both associated with childhood body fat, but weight change patterns in infancy tended to have larger effects. Fetal growth restriction followed by infant growth acceleration was associated with increased visceral and liver fat

Physicochemical characteristics of cu/zn/g-al2o3 catalyst and its mechanistic study in transesterification for biodiesel production

A series of novel mixed metal oxide catalysts with the incorporation of copper as a dopant supported on zinc-alumina (Cu/Zn/γ-Al2O3) for biodiesel production have been synthesized and characterized. ZnO is a solid base catalyst, but its weak surface basic properties have limited the usage of ZnO in the transesterification reaction of refined used cooking oil to biodiesel. To further improve the catalytic activity, the copper dopant was loaded by the wetness impregnation method. Cu/Zn/γ-Al2O3 catalyst of 10:90 wt% dopant-to-based (ZnO) ratio with calcination at 800 °C exhibited the highest biodiesel yield (89.5%) at optimum reaction conditions (65 °C, 10 wt% catalyst loading, 1:20 oil-to-methanol mol ratio and 2 h reaction time). The N2 adsorption-desorption and CO2-temperature programmed desorption analyses indicated that the material possessed a high surface area (149 m2/g) and high basicity (3.7424 mmol/g). The mechanistic study confirmed the catalytic reaction followed the Langmuir-Hinshelwood (LH) model, which involves the initial adsorption of reactants molecules on active sites of the catalyst surface

Ethnic differences in childhood right and left cardiac structure and function assessed by cardiac magnetic resonance imaging

Ethnic differences in cardiovascular risk factors and disease are well-known and may originate in early-life. We examined the ethnic differences in cardiac structure and function in children using cardiac magnetic resonance imaging in a European migrant population, and whether any difference was explained by early life factors. We used a prospective population-based cohort study among 2317 children in Rotterdam, the Netherlands. We compared children from Dutch (73%), Cape Verdean (3.5%), Dutch Antillean (3.3%), Moroccan (6.1%), Surinamese-Creoles (3.9%), Surinamese-Hindustani (3.4%), and Turkish (6.4%) background. Main outcomes were cMRI-measured cardiac structures and function. Cardiac outcomes were standardized on body surface area. Cape Verdean, Surinamese-Hindustani, and Turkish children had smaller right ventricular end-diastolic volume and left ventricular end-diastolic volume relative to their body size than Dutch children (p < 0.05). These results were not fully explained by fetal and childhood factors. Right ventricular ejection fraction and left ventricular ejection fraction did not differ between ethnicities after adjustment for fetal and childhood factors. Conclusion: Right ventricular end-diastolic volume and left ventricular end-diastolic volume differ between ethnic subgroups in childhood, without affecting ejection fraction. Follow-up studies are needed to investigate whether these differences lead to ethnic differences in cardiac disease in adulthood.What is Known:center dot Ethnic differences in cardiovascular risk factors and disease are well-known and may originate in early-life.center dot The prevalence of cardiovascular disease differs between ethnic groups. What is New:center dot We examined ethnic differences in left and right cardiac structure and function in children using cMRI.center dot Right and left cardiac dimensions differ between ethnic groups in childhood and are only partly explained by fetal and childhood factors