Selma H. Bouthoorn

Ethnic Differences in Blood Pressure and Hypertensive Complications During Pregnancy: The Generation R Study

The aim was to investigate ethnic differences in blood pressure levels in each trimester of pregnancy and the risk of gestational hypertensive disorders and the degree to which such differences can be explained by education and lifestyle-related factors. The study included 6215 women participating in a population-based prospective cohort study from early pregnancy onward in Rotterdam. Ethnicity was assessed at enrollment. Blood pressure was measured in each trimester. Information about gestational hypertensive disorders was available from medical charts. Lifestyle factors included smoking, alcohol, caffeine intake, folic acid supplementation, sodium and energy intake, body mass index, and maternal stress. Associations and explanatory pathways were investigated using linear and logistic regression analysis. Dutch pregnant women had higher systolic blood pressure levels as compared with women in other ethnic groups in each trimester of pregnancy. Compared with Dutch women, Turkish and Moroccan women had lower diastolic blood pressure levels in each trimester. These differences remained after adjusting for education and lifestyle factors. Turkish and Moroccan women had a lower risk of gestational hypertension as compared with Dutch women (odds ratio, 0.32 [95% CI, 0.18–0.58] and odds ratio, 0.28 [95% CI, 0.14–0.58]), and Cape Verdean women had an elevated risk of preeclampsia (odds ratio, 2.22 [95% CI, 1.22–4.07]). Differences could not be explained by education or lifestyle. Substantial ethnic differences were observed in blood pressure levels and risk of gestational hypertensive disorders in each trimester of pregnancy, and a wide range of variables could not explain these differences.

Determinants of Ethnic Differences in Cytomegalovirus, Epstein-Barr Virus, and Herpes Simplex Virus Type 1 Seroprevalence in Childhood.

OBJECTIVE To identify whether there are ethnic differences in cytomegalovirus (CMV), Epstein-Barr virus (EBV), and herpes simplex virus type 1 (HSV-1) seroprevalence rates in children at 6 years of age, and when present, to evaluate how these differences can be explained by sociodemographic and environmental factors. STUDY DESIGN This study was embedded within a multi-ethnic population-based prospective cohort study. Serum IgG levels against CMV, EBV, and HSV-1 were measured by enzyme-linked immunosorbent assay in 4464 children (median age 6.0 years). Information on demographics and characteristics were assessed by questionnaires. Herpesvirus seroprevalences between Surinamese-Creole, Surinamese-Hindustani, Turkish, Moroccan, Cape Verdean Antillean, and Native Dutch children were compared. RESULTS Non-Western ethnicity was an independent risk factor for CMV (aOR, 2.16; 95% CI 1.81-2.57), EBV (1.76; 1.48-2.09), and HSV-1 seropositivity (1.52; 1.39-1.66). Among the ethnic groups, CMV seroprevalences ranged between 29% and 65%, EBV between 43% and 69%, and HSV-1 between 13% and 39%. Low family net household income, low maternal educational level, crowding, and lifestyle factors explained up to 48% of the ethnic differences in HSV-1 seroprevalences, and up to 39% of the ethnic differences in EBV seroprevalences. These factors did not explain ethnic differences in CMV seroprevalences. CONCLUSIONS Socioeconomic position and factors related to lifestyle explain only a part of the large ethnic differences in EBV and HSV-1 seroprevalences, whereas they do not explain ethnic differences in CMV seroprevalences in childhood.

Development of socioeconomic inequalities in obesity among Dutch pre-school and school-aged children

To investigate the emergence of the inverse socioeconomic gradient in body mass index (BMI) in the first 6 years of life. Furthermore, associations of socioeconomic position (SEP) with BMI and total fat mass (%) were assessed at age 6, and potential mediating factors in the pathway between SEP and childrens body composition were investigated.

Genetic taste blindness to bitter and body composition in childhood: a Mendelian randomization design

Background:The ability to taste 6-n-propylthiouracil (PROP) may be associated with body composition, but previous findings from observational studies are conflicting and cannot be interpreted causally. The aim of this study was to estimate the causal association between PROP taster status and body composition in a population-based cohort study.Methods:The study was embedded in a population-based prospective birth cohort study. The TAS2R38 genotype (rs713598) was used as an instrumental variable (IV) to obtain unbiased effect estimates of the relation between PROP taster status and body weight (n=3778). Adiposity measures included body mass index (BMI) and fat mass measured by dual- energy X-ray absorptiometry scan at the child’s age of 6 years. Associations were investigated using both ordinary linear regression (OLS) and two-stage least squares regression (2SLS).Results:Non-taster girls had higher BMI standard deviation scores (SDS) and higher body fat as compared with taster girls (results from linear regression BMI SDS: –0.09, P=0.023, body fat mass (%): −0.49, P=0.028). The TAS2R38 genotype predicted PROP phenotype (F=240), indicating a strong IV. The 2SLS effect estimates were imprecise but similar to the observational estimates (−0.08 for BMI SDS and −0.46 for body fat mass %) and were not significantly different from the OLS results (Hausman test: P>0.10). For boys there were no differences observed between tasters and non-tasters.Conclusions:Our findings suggest a causal relation between PROP taster status and body weight among 6-year-old girls; Mendelian randomization was consistent with conventional estimates. In contrast, body weight among boys appeared to be independent of the PROP taster status. Further research should focus on possible underlying pathways, such as dietary behavior.

Sedentary behaviors, physical activity behaviors, and body fat in 6-year-old children: The Generation R Study

BackgroundChildhood overweight and obesity is a major public health concern. Knowledge on modifiable risk factors is needed to design effective intervention programs. This study aimed to assess associations of children’s sedentary behaviors (television viewing and computer game use) and physical activity behaviors (sports participation, outdoor play, and active transport to/from school) with three indicators of body fat, i.e., percent fat mass, body mass index (BMI) standard deviation scores, and weight status (normal weight, overweight).MethodsCross-sectional data from 5913 6-year-old ethnically diverse children were analyzed. Children’s weight and height were objectively measured and converted to BMI. Weight status was defined according to age- and sex-specific cut-off points of the International Obesity Task Force. BMI standard deviation scores were created, based on Dutch reference growth curves. Fat mass was measured my dual-energy X-ray absorptiometry (DXA). Sedentary and physical activity behaviors were assessed by parent-reported questionnaires. Series of logistic and linear regression analyses were performed, controlling for confounders (i.e., socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors).ResultsSports participation was inversely associated with fat mass (p < 0.001), even after adjustment for socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors. No other independent associations were observed.ConclusionsThe results of this study indicate that sports participation is inversely associated with percent body fat among ethnically diverse 6-year-old children. More research in varied populations including objective measurements and longitudinal designs are needed to confirm these current results.

Early origins of ethnic disparities in cardiovascular risk factors

BACKGROUND Not much is known about the ethnic differences in cardiovascular risk factors during childhood in European countries. We examined the ethnic differences in childhood cardiovascular risk factors in the Netherlands. METHODS In a multi-ethnic population-based prospective cohort study, we measured blood pressure, left ventricular mass, and levels of cholesterol, triglyceride and insulin at the median age of 6.2years. RESULTS As compared to Dutch children, Cape Verdean and Turkish children had a higher blood pressure, whereas Cape Verdean, Surinamese-Creole and Turkish children had higher total-cholesterol levels (p-values<0.05). Turkish children had higher triglyceride levels, but lower insulin levels than Dutch children (p-values<0.05). As compared to Dutch children, only Turkish children had an increased risk of clustering of cardiovascular risk factors (odds ratio: 2.45 (95% confidence interval 1.18, 3.37)). Parental pre-pregnancy factors explained up to 50% of the ethnic differences in childhood risk factors. In addition to these factors, pregnancy and childhood factors and childhood BMI explained up to 50%, 12.5% and 61.1%, respectively. CONCLUSIONS Our results suggest that compared to Dutch children, Cape Verdean, Surinamese-Creole and Turkish children have an adverse cardiovascular profile. These differences are largely explained by parental pre-pregnancy factors, pregnancy factors and childhood BMI.

Maternal educational level and blood pressure, aortic stiffness, cardiovascular structure and functioning in childhood : The generation R study

BACKGROUND In adults, low level of education was shown to be associated with higher blood pressure levels and alterations in cardiac structures and function. It is currently unknown whether socioeconomic inequalities in arterial and cardiac alterations originate in childhood. Therefore, we investigated the association of maternal education with blood pressure levels, arterial stiffness, and cardiac structures and function at the age of 6 years and potential underlying factors. METHODS The study included 5,843 children participating in a prospective cohort study in the Netherlands. Maternal education was assessed at enrollment. Blood pressure, carotid-femoral pulse wave velocity, left atrial diameter, aortic root diameter, left ventricular mass, and fractional shortening were measured at the age of 6 years. RESULTS Children with low educated (category 1) mothers had higher systolic (2.80mm Hg; 95% confidence interval (CI) = 1.62-2.94) and diastolic (1.80mm Hg; 95% CI = 1.25-2.35) blood pressure levels compared with children with high educated (category 4) mothers. The main explanatory factors were the childs body mass index (BMI), maternal BMI, and physical activity. Maternal education was negatively associated with fractional shortening (P trend = 0.008), to which blood pressure and childs BMI contributed the most. No socioeconomic gradient was observed in other arterial and cardiac measurements. CONCLUSIONS Socioeconomic inequalities in blood pressure are already present in childhood. Higher fractional shortening among children from low socioeconomic families might be a first cardiac adaptation to higher blood pressure and higher BMI. Interventions should be aimed at lowering child BMI and increasing physical activity among children from low socioeconomic families.

Socioeconomic inequalities in placental vascular resistance: a prospective cohort study

OBJECTIVE To examine the association between socioeconomic position (SEP) and umbilical and uterine placental resistance indices in the second and third trimester, and to what extent this could be explained by lifestyle-related behaviors. DESIGN Prospective cohort study. SETTING Rotterdam, the Netherlands. PATIENT(S) 7,033 pregnant women of mean age (± standard deviation) 29.9 (±5.2) years. INTERVENTION(S) None. MAIN OUTCOME MEASURE(S) Uterine artery resistance index (UARI) and umbilical artery pulsatility index (UAPI) in second and third trimester measured with Doppler ultrasound. RESULT(S) Third-trimester UARI and both second- and third-trimester UAPI were statistically significantly higher for women with lower educational levels as compared with those with higher educational levels. Educational level was strongly associated with the risk of continuously high levels of UARI and UAPI from second to third trimester of pregnancy. Notching was not associated with SEP. Smoking was a significant contributor to the association of SEP and increased placental resistance indices; body mass index, folic acid supplementation use, and alcohol use were not. CONCLUSION(S) Women from low socioeconomic subgroups have higher placental resistance indices, which may cause a higher prevalence of pregnancy complications. This was mainly explained by maternal smoking during pregnancy.

Head Circumference of Infants Born to Mothers with Different Educational Levels; The Generation R Study

Objective Head circumference (HC) reflect growth and development of the brain in early childhood. It is unknown whether socioeconomic differences in HC are present in early childhood. Therefore, we investigated the association between socioeconomic position (SEP) and HC in early childhood, and potential underlying factors. Methods The study focused on Dutch children born between April 2002 and January 2006 who participated in The Generation R Study, a population-based prospective cohort study in Rotterdam, the Netherlands. Maternal educational level was used as indicator of SEP. HC measures were concentrated around 1, 3, 6 and 11 months. Associations and explanatory factors were investigated using linear regression analysis, adjusted for potential mediators. Results The study included 3383 children. At 1, 3 and 6 months of age, children of mothers with a low education had a smaller HC than those with a high education (difference at 1 month: −0.42 SD; 95% CI: −0.54,−0.30; at 3 months: −0.27 SD; 95% CI −0.40,−0.15; and at 6 months: −0.13 SD; 95% CI −0.24,−0.02). Child’s length and weight could only partially explain the smaller HC at 1 and 3 months of age. At 6 months, birth weight, gestational age and parental height explained the HC differences. At 11 months, no HC differences were found. Conclusion Educational inequalities in HC in the first 6 months of life can be mainly explained by pregnancy-related factors, such as birth weight and gestational age. These findings further support public health policies to prevent negative birth outcomes in lower socioeconomic groups.

Meal-Skipping Behaviors and Body Fat in 6-Year-Old Children.

OBJECTIVE To assess the prospective associations of breakfast, lunch, and dinner skipping at age 4 years with body fat (ie, percent fat mass, body mass index [BMI], and weight status) at age 6 years. STUDY DESIGN Data were analyzed from 5913 children participating in the Generation R Study, a population-based prospective cohort study in Rotterdam, The Netherlands. Meal-skipping behaviors were assessed through parent-report questionnaires. Childrens weight and height were objectively measured and converted to BMI SDSs. Weight status (ie, overweight or normal weight) was defined according to age- and sex-specific cutoff points. At age 6 years, percent fat mass was assessed by dual-energy X-ray absorptiometry. Linear and logistic regression analyses were performed, adjusting for covariates and BMI at age 4 years. RESULTS Breakfast skipping at age 4 years was associated with a higher percent fat mass at age 6 years (β = 1.38; 95% CI, 0.36-2.40). No associations were found with BMI or weight status. Furthermore, no associations were found between lunch and dinner skipping at age 4 years and body fat at age 6 years. CONCLUSION Breakfast skipping at age 4 years is associated with a higher percent fat mass at age 6 years. Further prospective studies, including intervention studies, are warranted to extend the evidence base on the directionality and causality of this association.