Social inequalities in pregnancy outcomes and early childhood behaviour: the Generation R study

aim of this thesis was to extend the existing knowledge on the relation of social disadvantage with pregnancy outcomes and early childhood behaviour. More specifically, we aimed to identify the mechanisms underlying this association. In this thesis, several indicators of social disadvantage are examined, namely low educational level, low income, unemployment (these three indicators are also labeled ‘low socioeconomic status’), and ethnic minority status. This thesis indicated that a large social gradient exists in pregnancy outcomes in women living in Rotterdam, the Netherlands: women with a low socioeconomic background, as compared to women with a high socioeconomic status, had an elevated risk of adverse pregnancy outcomes, such as slower fetal growth, preterm birth, and low birth weight. The inequalities were largely explained by a combination of risk factors for pregnancy complications among women with a low socioeconomic background, such as young age, short stature, smoking during pregnancy, experience of stress and psychosocial problems. Equally, we found a large social gradient in behaviour early in life with infants of low socioeconomic status displaying more temperamental difficulties, and toddlers of non-Dutch origin having higher levels of parent-reported behavioural problems. The social gradient was also observed in parenting style with parents of low SES or non-Dutch origin being more likely to harshly discipline their 3-year old children. The social gradient in early childhood behaviour was mainly explained by sociodemographic risk factors (e.g. young parental age, single motherhood) and indicators of stress and psychosocial problems of the parents. We also showed that the reported behavioural problems of non-Dutch toddlers were more pronounced among those with unfavourable maternal immigration characteristics, such as poor Dutch language skills and not feeling accepted by Dutch natives

Prevalence of bullying and victimization among children in early elementary school:Do family and school neighbourhood socioeconomic status matter?

BACKGROUND: Bullying and victimization are widespread phenomena in childhood and can have a serious impact on well-being. Children from families with a low socioeconomic background have an increased risk of this behaviour, but it is unknown whether socioeconomic status (SES) of school neighbourhoods is also related to bullying behaviour. Furthermore, as previous bullying research mainly focused on older children and adolescents, it remains unclear to what extent bullying and victimization affects the lives of younger children. The aim of this study is to examine the prevalence and socioeconomic disparities in bullying behaviour among young elementary school children. METHODS: The study was part of a population-based survey in the Netherlands. Teacher reports of bullying behaviour and indicators of SES of families and schools were available for 6379 children aged 5–6 years. RESULTS: One-third of the children were involved in bullying, most of them as bullies (17%) or bully-victims (13%), and less as pure victims (4%). All indicators of low family SES and poor school neighbourhood SES were associated with an increased risk of being a bully or bully-victim. Parental educational level was the only indicator of SES related with victimization. The influence of school neighbourhood SES on bullying attenuated to statistical non-significance once adjusted for family SES. CONCLUSIONS: Bullying and victimization are already common problems in early elementary school. Children from socioeconomically disadvantaged families, rather than children visiting schools in disadvantaged neighbourhoods, have a particularly high risk of involvement in bullying. These findings suggest the need of timely bullying preventions and interventions that should have a special focus on children of families with a low socioeconomic background. Future studies are necessary to evaluate the effectiveness of such programs

Oxidation and fragmentation of plastics in a changing environment; from UV-radiation to biological degradation

Understanding the fate of plastics in the environment is of critical importance for the quantitative assessment of the biological impacts of plastic waste. Specially, there is a need to analyze in more detail the reputed longevity of plastics in the context of plastic degradation through oxidation and fragmentation reactions. Photo-oxidation of plastic debris by solar UV radiation (UVR) makes material prone to subsequent fragmentation. The fragments generated following oxidation and subsequent exposure to mechanical stresses include secondary micro- or nanoparticles, an emerging class of pollutants. The paper discusses the UV-driven photo-oxidation process, identifying relevant knowledge gaps and uncertainties. Serious gaps in knowledge exist concerning the wavelength sensitivity and the dose-response of the photo-fragmentation process. Given the heterogeneity of natural UV irradiance varying from no exposure in sediments to full UV exposure of floating, beach litter or air-borne plastics, it is argued that the rates of UV-driven degradation/fragmentation will also vary dramatically between different locations and environmental niches. Biological phenomena such as biofouling will further modulate the exposure of plastics to UV radiation, while potentially also contributing to degradation and/or fragmentation of plastics independent of solar UVR. Reductions in solar UVR in many regions, consequent to the implementation of the Montreal Protocol and its Amendments for protecting stratospheric ozone, will have consequences for global UV-driven plastic degradation in a heterogeneous manner across different geographic and environmental zones. The interacting effects of global warming, stratospheric ozone and UV radiation are projected to increase UV irradiance at the surface in localized areas, mainly because of decreased cloud cover. Given the complexity and uncertainty of future environmental conditions, this currently precludes reliable quantitative predictions of plastic persistence on a global scale

Associations of eczema phenotypes with emotional and behavioural problems from birth until school age. The Generation R Study.

Background Eczema phenotypes and emotional and behavioural problems are highly prevalent in childhood, but their mutual relationship is not fully clear. Objectives To examine the associations of eczema phenotypes with school-age emotional and behavioural problems, and the bidirectional associations of eczema and emotional and behavioural problems from birth until 10 years. Methods This study among 5265 individuals was embedded in a prospective population-based cohort study. Never, early transient, mid-transient, late transient and persistent eczema phenotypes were identified based on parent-reported, physician-diagnosed eczema from age 6 months until 10 years. Emotional (internalizing) and behavioural (externalizing) problems were measured repeatedly using the Child Behavior Checklist from age 15 to 10 years. Cross-lagged models were applied for bidirectional analyses. Results All eczema phenotypes were associated with more internalizing problems and attention problems at age 10 years, compared with never having eczema: range of Z-score differences 014 [95% confidence interval (CI) 001–027] to 039 (95% CI 018–060). Children with early transient eczema had more aggressive behaviour symptoms at age 10 years (Z = 016, 95% CI 005–027). Bidirectional analysis showed that eczema at 0–2 years was associated with more internalizing and externalizing problems at ages 3–6 and 10 years, while, inversely, only internalizing problems at 0–2 years were associated with an increased risk of eczema at age 10 years. Conclusions Eczema phenotypes are very modestly associated with more somatic symptoms and attention problems at school age. Early transient eczema is associated with more aggressive behaviour symptoms. Directional effects seem to occur from early-life eczema to later-life internalizing and externalizing problems, rather than the reverse

Parental depression and child well-being: Young children's self-reports helped addressing biases in parent reports

Objectives Effects of maternal and paternal depression on child development are typically evaluated using parental reports of child problems. Yet, parental reports may be biased. Methods In a population-based cohort, parents reported lifetime depression (N = 3,178) and depressive symptoms (N = 3,131). Child emotional and behavioral problems were assessed at age 6 years by child self-report using the Berkeley Puppet Interview, by mother report using the Child Behavior Checklist (CBCL), and at age 3 years by father and mother reported CBCLs. Results Both maternal and paternal depression was associated with more child problems. Associations were of similar strength if child problems were obtained by self-reports. However, if parents reported about their own depression or depressive symptoms and about their child's problems, estimates were generally stronger for associations with the reporting parent's depression as the determinant. For instance, if mothers reported child emotional problems, associations were stronger for maternal (B = 0.27; 95% confidence interval (CI) = 0.19, 0.35) than for paternal lifetime depression (B = 0.12; 95% CI = 0.02, 0.21; P-value for difference = 0.02). Conclusion Depression of mothers and fathers affects young children's well-being. However, if parents reported about their own depression and about child problems, associations were inflated. To accurately estimate effects of parental depression, multiple-source data including young children's perspectives must be considered

Musculoskeletal pain in 6-year-old children: the Generation R Study

Musculoskeletal (MSK) pain is frequently reported among adolescents and children and is a common reason for consultation in primary care. Our aim is to examine its prevalence in 6-year-old children in a general population and to assess associations with physical and psychosocial factors. Data from the Generation R Study, a population-based cohort, was used. Prevalence and characteristics of MSK pain were assessed with parent-reported questionnaires at 6 years of age (N = 6200). Demographics and data on physical activity, sedentary behaviors, previous reported MSK pain, and behavioral problems were extracted from questionnaires. The body mass index SD score was calculated from objectively measured weight and height. A 3-month prevalence of 10.0% was found for MSK pain in children, of which one-third was chronic, and 44.6% experienced together with pain at other sites. Univariate analyses showed that boys and children with lower socioeconomic status reported MSK pain more frequently compared to other pain and no pain. Although no associations were found between MSK pain and children's body mass index and physical activity level, children with MSK pain were more likely to watch television ≥2 hours/day. Multivariable analysis showed significant associations for MSK pain at 3 years of age (odds ratio 5.10, 95% confidence interval 3.25-7.98) and behavioral problems (odds ratio 2.10, 95% confidence interval 1.19-3.72) with the presence of MSK pain. So, MSK pain is already common in young children and is often chronic or recurrent. Previous reported MSK pain and behavioral

Prevalence of bullying and victimization among children in early elementary school: Do family and school neighbourhood socioeconomic status matter?

Background: Bullying and victimization are widespread phenomena in childhood and can have a serious impact on well-being. Children from families with a low socioeconomic background have an increased risk of this behaviour, but it is unknown whether socioeconomic status (SES) of school neighbourhoods is also related to bullying behaviour. Furthermore, as previous bullying research mainly focused on older children and adolescents, it remains unclear to what extent bullying and victimization affects the lives of younger children. The aim of this study is to examine the prevalence and socioeconomic disparities in bullying behaviour among young elementary school children. Methods. The study was part of a population-based survey in the Netherlands. Teacher reports of bullying behaviour and indicators of SES of families and schools were available for 6379 children aged 5-6 years. Results: One-third of the children were involved in bullying, most of them as bullies (17%) or bully-victims (13%), and less as pure victims (4%). All indicators of low family SES and poor school neighbourhood SES were associated with an increased risk of being a bully or bully-victim. Parental educational level was the only indicator of SES related with victimization. The influence of school neighbourhood SES on bullying attenuated to statistical non-significance once adjusted for family SES. Conclusions: Bullying and victimization are already common problems in early elementary school. Children from socioeconomically disadvantaged families, rather than children visiting schools in disadvantaged neighbourhoods, have a particularly high risk of involvement in bullying. These findings suggest the need of timely bullying preventions and interventions that should have a special focus on children of families with a low socioeconomic background. Future studies are necessary to evaluate the effectiveness of such programs

Bullying and Victimization Among Young Elementary School Children: The Role of Child Ethnicity and Ethnic School Composition

School-aged children with an ethnic minority background are relatively often involved in bullying and victimization, but the role of ethnic composition of schools in this context remains unclear. This study examined the relation between ethnic minority background, ethnic school composition, and bullying behaviour around primary school entry in the Netherlands. The study was based on a 2008/2009 school survey in Rotterdam, a Dutch city where about 50 % of children have a non-Dutch background. For 8523 children, teacher reports of bullying behaviour at age 5–6 years were available. Children with a non-Dutch background had higher odds of being a victim (adjusted OR 1.41, 95 % CI 1.11, 1.80), bully (OR 1.38, 95 % CI 1.20, 1.58) or bully-victim (OR 1.38, 95 % CI 1.19, 1.62) than children of Dutch national origin. Ethnic diversity in schools increased children’s risk of bullying behaviour (e.g. ORvictim per 0.1 increase in 0–1 diversity range = 1.06, 95 % CI 1.00, 1.13), with children of both Dutch and non-Dutch national origin relatively more often involved in bullying in ethnically diverse schools. The proportion of same-ethnic peers in school reduced the risk of bullying among children of Dutch national origin (e.g. ORvictim per 10 % more same-ethnic children = 0.90, 95 % CI 0.83, 0.98), but not among non-Dutch children. In conclusion, ethnic minority background and ethnic diversity within schools are risk factors for bullying among 5–6 year olds. Plausibly, reductions in absolute numbers of bullying events may be obtained with tailor-made interventions in ethnically diverse schools. Such interventions should preferably be offered early in the school curriculum