Maternal educational level and risk of gestational hypertension: the Generation R Study

We examined whether maternal educational level as an indicator of socioeconomic status is associated with gestational hypertension. We also examined the extent to which the effect of education is mediated by maternal substance use (that is smoking, alcohol consumption and illegal drug use), pre-existing diabetes, anthropometrics (that is height and body mass index (BMI)) and blood pressure at enrollment. This was studied in 3262 Dutch pregnant women participating in the Generation R Study, a population-based cohort study. Level of maternal education was established by questionnaire at enrollment, and categorized into high, mid-high, mid-low and low. Diagnosis of gestational hypertension was retrieved from medical records using standard criteria. Odds ratios (OR) of gestational hypertension for educational levels were calculated, adjusted for potential confounders and additionally adjusted for potential mediators. Adjusted for age and gravidity, women with mid-low (OR: 1.52; 95% CI: 1.02, 2.27) and low education (OR: 1.30; 95% CI: 0.80, 2.12) had a higher risk of gestational hypertension than women with high education. Additional adjustment for substance use, pre-existing diabetes, anthropometrics and blood pressure at enrollment attenuated these ORs to 1.09 (95% CI: 0.70, 1.69) and 0.89 (95% CI: 0.50, 1.58), respectively. These attenuations were largely due to the effects of BMI and blood pressure at enrollment. Women with relatively low educational levels have a higher risk of gestational hypertension, which is largely due to higher BMI and blood pressure levels from early pregnancy. The higher risk of gestational hypertension in these women is probably caused by pre-existing hypertensive tendencies that manifested themselves during pregnancy.     

Paediatric population neuroimaging and the Generation R Study: the second wave

Paediatric population neuroimaging is an emerging field that falls at the intersection between developmental neuroscience and epidemiology. A key feature of population neuroimaging studies involves large-scale recruitment that is representative of the general population. One successful approach for population neuroimaging is to embed neuroimaging studies within large epidemiological cohorts. The Generation R Study is a large, prospective population-based birth-cohort in which nearly 10,000 pregnant mothers were recruited between 2002 and 2006 with repeated measurements in the children and their parents over time. Magnetic resonance imaging was included in 2009 with the scanning of 1070 6-to-9-year-old children. The second neuroimaging wave was initiated in April 2013 with a total of 4245 visiting the MRI suite and 4087 9-to-11-year-old children being scanned. The sequences included high-resolution structural MRI, 35-direction diffusion weighted imaging, and a 6 min and 2 s resting-state functional MRI scan. The goal of this paper is to provide an overview of the imaging protocol and the overlap between the neuroimaging data and metadata. We conclude by providing a brief overview of results from our first wave of neuroimaging, which highlights a diverse array of questions that can be addressed by merging the fields of developmental neuroscience and epidemiology.     

High circulating folate and vitamin B-12 concentrations in women during pregnancy are associated with increased prevalence of atopic dermatitis in their offspring

Recent studies suggest that in utero exposure of methyl donors influences programming of the fetal immune system in favor of development of allergic disease. The aim of this study was to assess whether the MTHFR C677T polymorphism, folic acid supplementation, and circulating folate and vitamin B-12 concentrations during pregnancy were associated with wheezing, shortness of breath, and atopic dermatitis in offspring. The study was a population-based birth cohort from fetal life until 48 mo (n = 8742). The use of folic acid supplementation during pregnancy was assessed by questionnaire. Plasma folate and serum vitamin B-12 concentrations and the MTHFR C677T polymorphism were available from blood collected in early pregnancy. Atopic dermatitis, wheezing, and shortness of breath in the offspring were assessed by parental-derived questionnaires at 12, 24, 36, and 48 mo. Maternal folate >16.2 nmol/L and vitamin B-12 >178 pmol/L were positively associated with the development of atopic dermatitis [adjusted OR: 1.18 (95% CI: 1.05-1.33) and adjusted OR: 1.30 (95% CI: 1.06-1.60) for the highest quartiles of folate and vitamin B-12 concentrations, respectively] but not with wheezing and shortness of breath. Maternal MTHFR C677T polymorphism and folic acid supplementation were not associated with wheezing, shortness of breath, and atopic dermatitis. No interactions were found by age, family history of atopy, folic acid supplementation, MTHFR C677T polymorphism, or maternal smoking (P-interaction > 0.10). High folate and vitamin B-12 levels during pregnancy are associated with increased prevalence of atopic dermatitis in the offspring. Potential risks of high folate and vitamin B-12 concentrations on allergic outcomes should be evaluated when discussing mandatory fortification programs.     

Air Pollution Exposure and Markers of Placental Growth and Function: The Generation R Study

Background: Air pollution exposure during pregnancy might affect placental growth and function, perhaps leading to pregnancy complications.Objective: We prospectively evaluated the associations of maternal air pollution exposure with markers of placental growth and function among 7,801 pregnant women in the Netherlands.Methods: We estimated levels of particulate matter ≤ 10 µm in aerodynamic diameter (PM₁₀) and nitrogen dioxide (NO₂) at the home address for different periods during pregnancy using dispersion modeling techniques. Pro- and anti-angiogenic factors [placental growth factor (PlGF) and soluble fms-like tyrosine kinase 1 (sFlt-1), respectively] were measured in first- and second-trimester maternal blood and in fetal cord blood samples at delivery. Pulsatility index of the uterine and umbilical arteries was measured by Doppler ultrasound in second and third trimester, and notching was assessed in third trimester. Placenta weight and birth weight were obtained from medical records.Results: Higher PM₁₀ and NO₂ exposure levels were associated with lower second-trimester maternal sFlt-1 and PlGF levels. PM₁₀ and NO₂ exposures averaged over total pregnancy were associated with higher sFlt-1 and lower PlGF levels in fetal cord blood, consistent with an anti-angiogenic state. PM₁₀ and NO₂ exposures were not consistently associated with second- or third-trimester placental resistance indices. NO₂ exposure was associated with third-trimester notching (odds ratio 1.33; 95% CI: 0.99, 1.78 per 10-µg/m³ increase in the prior 2 months). PM₁₀ and NO₂ exposures were associated with lower placenta weight (–11.8 g; 95% CI: –20.9, –2.7, and –10.7 g; 95% CI: –19.0, –2.4, respectively, per 10-µg/m³ increase in the prior 2 months), but not with placenta to birth weight ratio.Conclusions: Our results suggest that maternal air pollution exposure may influence markers of placental growth and function. Future studies are needed to confirm these findings and explore the maternal and fetal consequences.     

An observational study on socio-economic and ethnic differences in indicators of sedentary behavior and physical activity in preschool children

Objective

We studied associations between social disadvantage and indicators of sedentary behavior and physical activity at preschool age.

Methods

Data from 4688 children enrolled in a birth cohort in Rotterdam, the Netherlands, between 2002 and 2006 were analyzed. Indicators of sedentary behavior (watching television ≥ 2 h/day and sitting in a buggy ≥ 0.5 h/day) and physical inactivity (playing outside < 3 h/day) were measured by a parent-reported questionnaire at age 3. Adjustments were made for social circumstances and indicators of health behaviors. Logistic regression was used to obtain odds ratios (OR) and 95% confidence intervals (CI).

Results

Children with low-educated mothers (OR: 3.27, 95% CI 2.12-5.05) and non-Dutch children (OR_nonWestern: 2.67, 95% CI 2.04-3.49, OR_Western: 2.09, 95% CI 1.42-3.0) were more likely to watch television for at least 2 h/day. Similar results were seen for sitting in a buggy for at least 0.5 h/day. Non western children were more likely to play outside for less than 3 h/day (OR: 1.95, 95% CI: 1.39-2.73) than native Dutch children, while no differences were seen for other western children or children from mothers with a low educational level.

Conclusions

Socio-economic status and ethnicity are already associated with indicators of sedentary lifestyles at preschool age.     

Increased risk of exceeding entertainment-media guidelines in preschool children from low socioeconomic background: The Generation R Study

ObjectiveTo describe and explain the association between maternal educational level and television viewing time among preschool children.MethodWe analyzed data from 2786 preschoolers enrolled in a birth cohort study in Rotterdam, The Netherlands, between 2002 and 2006. Odds ratios of watching television ≥ 2 hours/day and ≥ 1 hour/day were calculated for children of mothers with low, mid-low, and mid-high educational level (reference group: high educational level), before and after adjustment for mediators.ResultsChildren of low, mid-low, and mid-high educated mothers were more likely to watch television ≥ 2 hours/day compared to children of high educated mothers, with children of low educated mother showing the highest risk (OR: 11.32; 95% CI: 6.58, 19.46). Adjustment for mediators (i.e. maternal body mass index, parental television viewing, presence of a television set in the child's bedroom, and financial difficulties) led to a nearly 50% reduction in odds ratio for the lowest educational group (OR: 6.61; 95% CI: 3.69, 11.84). A similar educational gradient was found for watching television ≥ 1 hour/day, although effect estimates were smaller.ConclusionMaternal education is inversely associated with preschoolers' television viewing time. This association was partly explained by known correlates of children's television viewing.