Design of the 18-year follow-up of the Danish COPSAC birth cohort.

Background: Atopic diseases, obesity and neuropsychiatric disorders are lifestyle-related and environmental-related chronic inflammatory disorders, and the incidences have increased in the last years.

Objective: To outline the design of the 18-year follow-up of the Copenhagen Prospective Study on Asthma in Childhood (COPSAC) birth cohort, where risk factors of atopic diseases, obesity and neuropsychiatric disorders are identified through extensive characterisation of the environment, along with deep clinical phenotyping and biosampling for omics profiling.

Methods: COPSAC is a Danish prospective clinical birth cohort study of 411 children born to mothers with asthma who were enrolled at 1 month of age and closely followed at the COPSAC clinical research unit through childhood for the development of atopic diseases.

Covid-19 infection and vaccination during first trimester and risk of congenital anomalies: Nordic registry based study.

Objectives: To evaluate the risk of major congenital anomalies according to infection with or vaccination against covid-19 during the first trimester of pregnancy.

Design: Prospective Nordic registry based study.

Setting: Sweden, Denmark, and Norway.

Stress and anxiety during pregnancy and length of gestation: a federated study using data from five Canadian and European birth cohorts.

While its etiology is not fully elucidated, preterm birth represents a major public health concern as it is the leading cause of child mortality and morbidity. Stress is one of the most common perinatal conditions and may increase the risk of preterm birth. In this paper we aimed to investigate the association of maternal perceived stress and anxiety with length of gestation.

The relation between preterm birth and self-reported spinal pain in pre-adolescence-a study of 47,063 subjects from the Danish National Birth Cohort.

Unlabelled: Repeated exposure to pain and stress in early life may cause alterations in pain sensitivity later in life. Children born preterm are often exposed to painful invasive procedures. This study aimed to explore the relationship between being born preterm and self-report of spinal pain in pre-adolescence.

Associations of Maternal Educational Level, Proximity to Green Space During Pregnancy, and Gestational Diabetes With Body Mass Index From Infancy to Early Adulthood: A Proof-of-Concept Federated Analysis in 18 Birth Cohorts.

International sharing of cohort data for research is important and challenging. We explored the feasibility of multicohort federated analyses by examining associations between 3 pregnancy exposures (maternal education, exposure to green vegetation, and gestational diabetes) and offspring body mass index (BMI) from infancy to age 17 years. We used data from 18 cohorts (n = 206,180 mother-child pairs) from the EU Child Cohort Network and derived BMI at ages 0-1, 2-3, 4-7, 8-13, and 14-17 years.

Association between preeclampsia in daughters and risk of cardiovascular disease in parents.

Preeclampsia and cardiovascular disease (CVD) might share heritable underlying mechanisms. We investigated whether preeclampsia in daughters is associated with CVD in parents. In a register-based cohort study, we used Cox regression to compare rates of CVD (ischemic heart disease, ischemic stroke, myocardial infarction) in parents with ≥ 1 daughters who had preeclampsia and parents whose daughters did not have preeclampsia in Denmark, 1978-2018.

Gestational age and trajectories of body mass index and height from birth through adolescence in the Danish National Birth Cohort.

Preterm birth is associated with smaller body dimensions at birth. The impact on body size in later life, measured by body mass index (BMI) and height, remains unclear. A prospective register-based cohort study with 62,625 singletons from the Danish National Birth Cohort born 1996-2003 for whom information on gestational age (GA) at birth, length or weight at birth, and at least two growth measurements scheduled at the ages of 5 and 12 months, and 7, 11 and 18 years were available.

Joint exposure to parental cancer and income loss during childhood and the child's socioeconomic position in early adulthood: a Danish and Norwegian register-based cohort study.

Background: Parental cancer as well as economic hardship in the family during childhood can affect the child negatively. Our aim was to examine the association between the joint exposure to parental cancer and income loss in childhood and the child's socioeconomic position in early adulthood.

Methods: We conducted a register-based prospective cohort study of children born in Denmark between 1978 and 1986 and in Norway between 1979 and 1987.

Fetal death after the introduction of COVID-19 mitigation measures in Sweden, Denmark and Norway: a registry-based study.

It remains unclear whether the rate of fetal death has changed during the COVID-19 pandemic. We assessed the impact of COVID-19 mitigation measures on fetal death in Sweden (449,347 births), Denmark (290,857 pregnancies) and Norway (261,057 pregnancies) using robust population-based registry data. We used Cox regression to assess the impact of the implementation of pandemic mitigation measures on March 12th, 2020, on miscarriage (fetal loss before gestational week 22) and stillbirth (fetal loss after gestational week 22).

Maternal fever during pregnancy and male offspring reproductive health: A longitudinal cohort study in young Danish males.

Background: Maternal fever during pregnancy has been associated with an increased risk of genital malformations, but the implication for long-term reproductive health in the offspring is unknown.

Objectives: To investigate associations between timing, duration, and temperature of fetal exposure to maternal fever and sons' semen quality, testicular volume, and levels of reproductive hormones in early adulthood. Further, to examine whether concurrent use of antipyretics and/or antibiotics modified the effect.

Maternal stress during pregnancy and gestational duration: A cohort study from the Danish National Birth Cohort.

Background: Preterm birth is one of the most important contributors to neonatal mortality and morbidity. Experiencing stress during pregnancy may increase the risk of adverse birth outcomes, including preterm birth. This association has been observed in previous studies, but differences in measures used limit comparability.

Parental socio-economic position and the risk of type 1 diabetes in children and young adults in Denmark: A nation-wide register-based study.

Aim: Diabetes mellitus type 1 is one of the most common serious chronic diseases in childhood and the incidence is increasing. Insight into risk factors may inform our etiologic understanding of the disease and subsequent prevention. Any socio-economic gradient in disease risk indicates a potential for prevention, since this points towards socially patterned environmental risk factors.

The effect of gluten in adolescents and young adults with gastrointestinal symptoms: a blinded randomised cross-over trial.

Background: The popularity of the gluten-free diet and sales of gluten-free products have increased immensely.

Aims: To investigate whether gluten induces gastrointestinal symptoms, measured by self-reported questionnaires, as well as mental health symptoms in adolescents from a population-based cohort.

Methods: The eligible participants (n = 273) were recruited from a population-based cohort of 1266 adolescents and had at least four different gastrointestinal symptoms.

Mediation of the parental education gradient in early adult mortality by childhood adversity: a population-based cohort study of more than 1 million children.

Background: Children born into disadvantaged socioeconomic circumstances are more likely to experience both adversity during childhood and premature mortality. The aim of this study was to investigate how much of the parental education gradient in early adult mortality is explained by exposure to childhood adversity.

Methods: We used data from the nationwide register-based Danish Life Course cohort study.

Gestational Age, Parent Education, and Education in Adulthood.

Background: Adults born preterm (<37 weeks) have lower educational attainment than those born term. Whether this relationship is modified by family factors such as socioeconomic background is, however, less well known. We investigated whether the relationship between gestational age and educational attainment in adulthood differed according to parents' educational level in 4 Nordic countries.

Social, demographic and health characteristics of men fathering children at different ages.

The aim of this study was to examine associations between selected sociodemographic, socioeconomic, and health characteristics and the rates of fatherhood in different age groups. We investigated rates between 2011 and 2015 in a population-based register study including all men born from 1945 to 1995 residing in Denmark in 2011. The study population consisted of 1,867,108 men who fathered 268,612 children during the follow-up.

High Prevalence of Celiac Disease Among Danish Adolescents: A Population-based Study.

Objectives: The objective of this study was to establish an unselected cohort of Danish adolescents and estimate the prevalence of undiagnosed celiac disease (CeD).

Methods: The Glutenfunen cohort participants were recruited from an unselected subsample of the Danish National Birth Cohort, defined as participants living in the Island of Funen, Denmark. We invited all 7431 eligible participants in the age range of 15 to 21 years to a clinical visit.

Cause-Specific Stillbirth and Neonatal Death According to Prepregnancy Obesity and Early Gestational Weight Gain: A Study in the Danish National Birth Cohort.

Maternal obesity is associated with impaired fetal and neonatal survival, but underlying mechanisms are poorly understood. We examined how prepregnancy BMI and early gestational weight gain (GWG) were associated with cause-specific stillbirth and neonatal death. In 85,822 pregnancies in the Danish National Birth Cohort (1996-2002), we identified causes of death from medical records for 272 late stillbirths and 228 neonatal deaths.

The influence of parental age on timing of puberty: A study in the Danish National Birth Cohort.

Concerns have been raised about the potential negative biological effect of postponed parenthood upon the health of subsequent generations, including reproductive health. This study aimed to estimate if high parental age at birth was associated with accelerated pubertal timing in offspring. In this large-scale cohort study, 15,819 children born by mothers in the Danish National Birth Cohort from 2000 to 2003 participated in a nationwide puberty cohort (participation rate 71%).

Effect of Maternal Prepregnancy/Early-Pregnancy Body Mass Index and Pregnancy Smoking and Alcohol on Congenital Heart Diseases: A Parental Negative Control Study.

Background Congenital heart diseases (CHDs) are the most common congenital anomaly. The causes of CHDs are largely unknown. Higher prenatal body mass index (BMI), smoking, and alcohol consumption are associated with increased risk of CHDs.

Spinal pain in pre-adolescence and the relation with screen time and physical activity behavior.

Background: To investigate how screen time and physical activity behavior were associated with spinal pain in pre-adolescence.

Methods: This study included 45,555 pre-adolescents who participated in the 11-year follow-up of the Danish National Birth Cohort. The 11-year follow-up included self-reported information on computer and TV behavior, aspects of physical activity, as well as frequency and intensity of spinal pain (neck-, mid back- and low back pain).

Mortality Among Young Adults Born Preterm and Early Term in 4 Nordic Nations.

Importance: Adverse long-term outcomes in individuals born before full gestation are not confined to individuals born at extreme gestational ages. Little is known regarding mortality patterns among individuals born in the weeks close to ideal gestation, and the exact causes are not well understood; both of these are crucial for public health, with the potential for modification of risk.

Objective: To examine the risk of all-cause and noncommunicable diseases (NCD) deaths among young adults born preterm and early term.

Understanding pathways to inequalities in child mental health: a counterfactual mediation analysis in two national birth cohorts in the UK and Denmark.

Objectives: We assessed social inequalities in child mental health problems (MHPs) and how they are mediated by perinatal factors, childhood illness and maternal mental health in two national birth cohorts.

Design: Longitudinal cohort study SETTING: We used data from the UK Millennium Cohort Study and the Danish National Birth Cohort.

Primary And Secondary Outcome Measures: We applied causal mediation analysis to longitudinal cohort data.