Strengthening health visitors' breastfeeding support: Results from a cluster randomised study.

AIMS: To assess the effect of the education programme on three constructs of health visitors' breastfeeding support: knowledge, self-efficacy and action competence. Furthermore, the study aimed to confirm the factor structure of these three constructs. BACKGROUND: Health professionals are key in supporting breastfeeding women but studies report gaps in health professionals' breastfeeding support knowledge and competences. The present intervention study aimed to strengthen the breastfeeding support of families to improve breastfeeding rates. Health visitors received an interactive education programme to enhance their breastfeeding support knowledge, self-efficacy and action competence, including e-learning and a two-day course of lectures, role plays and discussions. DESIGN: A pre- and post-test study was applied in a cluster randomised trial METHODS: Cluster units were Danish municipal health visiting programmes, randomised by stratifying for region and annual births per cluster. Health visitors from 21 clusters (11 intervention, 10 control) participated. The knowledge, self-efficacy and action competence were assessed in self-reported questionnaires before and after education (n=368; intervention n=176, control n=196). To analyse the effects, the intention-to-treat principle and linear mixed models were applied. Confirmatory Factor Analysis was used to confirm the factor structures of the hypothesised knowledge, self-efficacy and action competence constructs. RESULTS: 158 health visitors in the control arm and 157 in the intervention arm completed the baseline questionnaire and were analysed in intention-to-treat analyses. 125 and 116, respectively, completed the follow-up questionnaire and were analysed in sensitivity analyses. Health visitors in both trial arms had high levels of self-efficacy and action competence at baseline. Mean treatment effect of the education programme was 0.5 points (CI95 % 0.1-0.8) for knowledge, 2.4 points (CI95 % 1.6-3.3) for self-efficacy and 1.4 points (CI95 % 0.7-2.0) for action competence. The factor structure of the items used to measure knowledge, self-efficacy and action competence were confirmed. CONCLUSIONS: The education programme improved the self-reported breastfeeding support knowledge, self-efficacy and action competence of health visitors. The factor structures of the instruments used to measure effects were confirmed by confirmatory factor analysis. TRIAL REGISTRATION: Clinical Trials: NCT05311631. First posted April 5, 2022.

The iceberg model of suicidal ideation and behaviour in Danish adolescents: integration of national registry and self-reported data within a national birth cohort.

Hospital records are used to identify suicide attempts in many countries but not all individuals present to hospital after a suicide attempt i.e., suggesting a 'hidden number'. Our aim was to present the prevalence of suicide ideation, plans, attempts, and suicides among Danish adolescents, including attempts not resulting in hospital contact. The study population consisted of participants in the Danish National Birth Cohort participating in an 18-year follow-up, with individual-level linkage to national register data. Prevalence was estimated with a variable with mutually exclusive categories ranging from no suicidality to self-reported suicide ideation, -plans, -attempt and hospital-recorded suicide attempt and stratified on sex and parental income. The 'hidden number' was estimated as the ratio between suicide attempts with and without hospital contact. Among 47 858 participants, all aged 18-years, 36% girls and 28% boys reported suicide ideation at least once in their life. In addition, 6% girls and 3% boys had either reported or been recorded with a suicide attempt. For every attempt recorded in the hospital setting, two girls (ratio, 1:2) and six boys (ratio, 1:6) reported having attempted suicide without hospital contact. The prevalence of any suicide attempt was 8% and 3% in the lowest and highest income group, respectively. Before age 18, 0·011% girls and 0·016% boys had died by suicide. In conclusion, suicidal ideation and behaviour are common in adolescents and there is a substantial 'hidden number' of adolescents with suicide attempt. These results emphasize the need for early age suicide preventive interventions in community-settings e.g., school environments.

Psoriasis and mental health in adolescents: A cross-sectional study within the Danish National Birth Cohort.

BACKGROUND: Psoriasis is a chronic skin disease associated with lower quality of life and higher risk of anxiety and depression in adults. We investigate whether adolescents with psoriasis also experience poorer mental health than their peers. METHODS: In this cross-sectional study, we included questionnaire data on psoriasis and mental health from the 18-year follow-up of the Danish National Birth Cohort. We estimated odds ratios (OR) and 95 % confidence intervals (CI) using a logistic regression with inverse probability weighting to account for potential selection bias, adjusted for potential confounders identified a priori. We estimated associations between self-reported psoriasis and multiple aspects of mental health (self-rated health, life satisfaction, mental well-being, loneliness, overall and internalizing behavioral difficulties, depressive symptoms, and anxiety symptoms). In sensitivity analyses, we examined doctor-diagnosed psoriasis and psoriasis with and without joint pain. RESULTS: Of the 44,838 included in this study, 1147 (2.6 %) reported psoriasis. Adolescents with psoriasis had a higher risk of nearly all outcomes, including depressive symptoms (OR 1.38; 1.19-1.58) and panic/agoraphobia among both males (OR 1.72; 1.33-2.19) and females (OR 1.60; 1.33-1.92). Associations attenuated when restricted to doctor-diagnosed psoriasis. Associations with poor mental health were mainly observed for adolescents with psoriasis also reporting joint pain. LIMITATIONS: We could not establish temporality and lacked data on joint pain in referents. CONCLUSION: Psoriasis is associated with poor mental health in adolescents. This appears to be driven by adolescents with psoriasis also reporting joint pain and is less evident in those with a doctor-confirmed diagnosis.

Maternal thyroid function in early pregnancy and offspring school performance and neurodevelopmental disorders.

CONTEXT: Thyroid hormones are critical for neural development, and during the first trimester of pregnancy the fetus relies fully on maternal thyroid hormone production. OBJECTIVE: To investigate the associations between maternal thyroid hormone levels in the first trimester with the child's school performance, risk of attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD). METHODS: From the Copenhagen Primary Care Laboratory Pregnancy Database information on first trimester TSH and fT4 measurements in mothers of children born in 2000-2014 were linked with information on the child's standardized test scores in school, ADHD (patient record diagnoses and medication) and ASD (patient record diagnoses) until end of 2018. Associations of TSH and fT4 with the outcomes were individually assessed by linear mixed models and Cox regression models. The analyses were stratified by preexisting maternal thyroid disorders. RESULTS: TSH measurements were available for 17,909 mother-child dyads. Among those with children born in 2000-2009, 6,126 had a standardized school test score and were analyzed for the association between maternal thyroid hormone levels and child's school performance, and no support for an association was found. The association between thyroid hormone levels and child's risk of ADHD and ASD were analyzed for the 17,909 dyads and with no support for an association between thyroid hormone levels and these neurodevelopmental disorders. Stratification by preexisting maternal thyroid disorders did not affect the results. CONCLUSIONS: We found no evidence for associations between first trimester maternal thyroid hormone levels and child's school performance, or risk of ADHD or ASD.

A Western Dietary Pattern during Pregnancy is Associated with Neurodevelopmental Disorders in Childhood and Adolescence.

Despite the high prevalence of neurodevelopmental disorders, there is a notable gap in clinical studies exploring the impact of maternal diet during pregnancy on child neurodevelopment. This observational clinical study examined the association between pregnancy dietary patterns and neurodevelopmental disorders, as well as their symptoms, in a prospective cohort of 10-year-old children (n=508). Data-driven dietary patterns were derived from self-reported food frequency questionnaires. A Western dietary pattern in pregnancy (per SD change) was significantly associated with attention-deficit / hyperactivity disorder (ADHD) (OR 1.66 [1.21 - 2.27], p=0.002) and autism diagnosis (OR 2.22 [1.33 - 3.74], p=0.002) and associated symptoms (p<0.001). Findings for ADHD were validated in three large (n=59725, n=656, n=348), independent mother-child cohorts. Objective blood metabolome modelling at 24 weeks gestation identified 15 causally mediating metabolites which significantly improved ADHD prediction in external validation. Temporal analyses across five blood metabolome timepoints in two independent mother-child cohorts revealed that the association of Western dietary pattern metabolite scores with neurodevelopmental outcomes was consistently significant in early to mid-pregnancy, independent of later child timepoints. These findings underscore the importance of early intervention and provide robust evidence for targeted prenatal dietary interventions to prevent neurodevelopmental disorders in children.

Transporting results in an observational epidemiology setting: purposes, methods, and applied example.

In the medical domain, substantial effort has been invested in generating internally valid estimates in experimental as well as observational studies, but limited effort has been made in testing generalizability, or external validity. Testing the external validity of scientific findings is nevertheless crucial for the application of knowledge across populations. In particular, transporting estimates obtained from observational studies requires the combination of methods for causal inference and methods to transport the effect estimates in order to minimize biases inherent to observational studies and to account for differences between the study and target populations. In this paper, the conceptual framework and assumptions behind transporting results from a population-based study population to a target population is described in an observational setting. An applied example to life-course epidemiology, where internal validity was constructed for illustrative purposes, is shown by using the targeted maximum likelihood estimator.

Urban environment in pregnancy and postpartum depression: An individual participant data meta-analysis of 12 European birth cohorts.

BACKGROUND: Urban environmental exposures associate with adult depression, but it is unclear whether they are associated to postpartum depression (PPD). OBJECTIVES: We investigated associations between urban environment exposures during pregnancy and PPD. METHODS: We included women with singleton deliveries to liveborn children from 12 European birth cohorts (N with minimum one exposure = 30,772, analysis N range 17,686-30,716 depending on exposure; representing 26-46 % of the 66,825 eligible women). We estimated maternal exposure during pregnancy to ambient air pollution with nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10), road traffic noise (Lden), natural spaces (Normalised Difference Vegetation Index; NDVI, proximity to major green or blue spaces) and built environment (population density, facility richness and walkability). Maternal PPD was assessed 3-18 months after birth using self-completed questionnaires. We used adjusted logistic regression models to estimate cohort-specific associations between each exposure and PPD and combined results via meta-analysis using DataSHIELD. RESULTS: Of the 30,772 women included, 3,078 (10 %) reported having PPD. Exposure to PM10 was associated with slightly increased odds of PPD (adjusted odd ratios (OR) of 1.08 [95 % Confidence Intervals (CI): 0.99, 1.17] per inter quartile range increment of PM10) whilst associations for exposure to NO2 and PM2.5 were close to null. Exposure to high levels of road traffic noise (≥65 dB vs. < 65 dB) was associated with an OR of 1.12 [CI: 0.95, 1.32]. Associations between green spaces and PPD were close to null; whilst proximity to major blue spaces was associated with increased risk of PPD (OR 1.12, 95 %CI: 1.00, 1.26). All associations between built environment and PPD were close to null. Multiple exposure models showed similar results. DISCUSSION: The study findings suggest that exposure to PM10, road traffic noise and blue spaces in pregnancy may increase PPD risk, however future studies should explore this causally.

Intergenerational transmission of tobacco smoking: The role of the child's behavioral difficulties. Data from the Danish National Birth cohort (DNBC).

AIMS: This study explores the role of offspring behavioral difficulties in the intergeneration transmission of tobacco smoking. METHODS: This longitudinal cohort study is based on children born in Denmark in 1996-2003 participating in the Danish National Birth Cohort (DNBC), followed-up until 18years of age. We included mother-child pairs with complete data regarding the exposure (4 trajectories of maternal daily smoking quantity during pregnancy: low, intermediate/stable, intermediate/decreasing and high), outcome (offspring daily smoking status at 18 years) and mediator (offspring symptoms of hyperactivity-inattention at 11 years), that is 24,588 mother-child pairs. RESULTS: In our study population, during pregnancy respectively 86.2%, 6.80%, 4.08% and 2.97% mothers belonged to the low, intermediate/stable, intermediate/decreasing and high smoking trajectory groups. After controlling for covariates using propensity scores, the direct effect of maternal smoking in pregnancy on offspring smoking in adolescence was statistically significant, especially when the mother belonged to the intermediate/stable smoking trajectory group (ORIPW = 2.09, 95% CI: 1.70 - 2.61) or to the high smoking trajectory group (ORIPW = 2.08, 95% CI: 1.52 - 3.11) compared to the low smoking trajectory group. None of the indirect effects of maternal smoking in pregnancy were statistically significant, and neither were the proportions mediated. CONCLUSION: Maternal pregnancy smoking seems to have an influence on offspring smoking in early adulthood, which does not appear to be mediated by offspring behavioral difficulties. Women should be strongly encouraged to quit smoking in pregnancy to reduce both short and long-term health risks among their offspring.

Body height and spinal pain in adolescence: a cohort study from the Danish National Birth Cohort.

OBJECTIVES: To investigate how body height and trajectories of height from infancy through childhood and adolescence were associated with spinal pain in pre- and late adolescence. METHODS: This prospective study included 43,765 individuals born into The Danish National Birth Cohort (DNBC) from 1996 to 2003. DNBC-data were linked with health and social data identified from Statistics Denmark registers. Spinal pain was self-reported in both the 11-year- and 18-year follow-up of DNBC and classified according to severity. Body height was measured from birth and onwards and further modelled as distinct developmental height trajectories by using latent growth curve modelling. Associations were estimated by using multinomial logistic regression models. RESULTS: Taller body height in childhood and adolescence was associated with approximately 20% increased likelihood of spinal pain in pre- and late adolescence among girls compared to their peers in the normal height group. For boys, taller body height was associated with spinal pain by late adolescence only. Spinal pain in pre-adolescence almost doubled the likelihood of spinal pain in late adolescence regardless of body height at age 18. Height trajectories confirmed the relationship for girls with the tall individuals being most likely to have spinal pain in both pre- and late adolescence. CONCLUSION: Tall body height during childhood and adolescence predisposes to spinal pain among girls in both pre-and late adolescence, and among boys in late adolescence. Body height is a contributing factor to the pathogenesis of spinal pain in adolescence; however, the mechanisms may be related to growth velocity, but for now uncertain.

A critical examination of Danish norms for the Strengths and Difficulties Questionnaire (SDQ).

OBJECTIVE: The objective was to describe observed differences between the official Danish Strengths and Difficulties Questionnaire (SDQ)-norms and data from a sample based on the Danish National Birth Cohort (DNBC) including children born between 1996 and 2003. We compared the risk classification, cut-off bandings and the group sizes between the Danish norms and the values found in our sample at ages 7, 11 and 18 years. RESULTS: Two sets of norms are used in Denmark: Arnfred's norms, based on a sample from one single Danish municipality and Niclasen's norms, based on multiple Danish cohorts, including the DNBC. Inconsistencies were found between banding scores in the two existing norms and the banding scores identified in our sample from DNBC: discrepancies included banding scores for several of the problem scales for children and preadolescents. For adolescents, we found less apparent inconsistencies between Arnfred's sample and the DNBC. Results demonstrate that the existing SDQ norms do not apply well to a large-scale cohort sample in Denmark. The usefulness of the SDQ as a screening instrument for mental health problems depends on appropriate norms. We therefore urge that the current Danish SDQ norms are used with caution, and preferably they should be revised.

Epigenome-Wide Associations of Placental DNA Methylation and Behavioral and Emotional Difficulties in Children at 3 Years of Age.

The placenta is a key organ for fetal and brain development. Its epigenome can be regarded as a biochemical record of the prenatal environment and a potential mechanism of its association with the future health of the fetus. We investigated associations between placental DNA methylation levels and child behavioral and emotional difficulties, assessed at 3 years of age using the Strengths and Difficulties Questionnaire (SDQ) in 441 mother-child dyads from the EDEN cohort. Hypothesis-driven and exploratory analyses (on differentially methylated probes (EWAS) and regions (DMR)) were adjusted for confounders, technical factors, and cell composition estimates, corrected for multiple comparisons, and stratified by child sex. Hypothesis-driven analyses showed an association of cg26703534 (AHRR) with emotional symptoms, and exploratory analyses identified two probes, cg09126090 (intergenic region) and cg10305789 (PPP1R16B), as negatively associated with peer relationship problems, as well as 33 DMRs, mostly positively associated with at least one of the SDQ subscales. Among girls, most associations were seen with emotional difficulties, whereas in boys, DMRs were as much associated with emotional than behavioral difficulties. This study provides the first evidence of associations between placental DNA methylation and child behavioral and emotional difficulties. Our results suggest sex-specific associations and might provide new insights into the mechanisms of neurodevelopment.

Comparison of prevalence and mental health problems across symptom frequency of self-reported symptoms of binge-eating disorder in a community sample of adolescents.

OBJECTIVE: Binge-eating disorder (BED) and subthreshold BED (SBED) are prevalent in adults and associated with mental health problems including depression, non-suicidal self-injury, lower quality of life, and suicidality. There is solid evidence that binge-eating behaviors are also prevalent in adolescence, but knowledge about mental health in community adolescents with BED of different frequency thresholds is more limited. We aimed to investigate the prevalence and mental health problems associated with SBED of low frequency and/or limited duration compared with BED in a Danish community sample of adolescents. METHODS: We included 2509 adolescents who completed the online survey of the 16-17-year follow-up of the Copenhagen Child Cohort (CCC2000), including items on BED symptoms approximating the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) criteria, and items on mental health and quality of life. RESULTS: The 1-year prevalence of SBED was 2.7% (95% confidence interval [CI]: 2.0%-3.3%) with a male:female ratio of 1:3.7; comparable to previous findings on BED in the same sample. SBED was also comparable to BED concerning cross-sectional associations with overall mental health problems, lower health-related quality of life, depressive symptoms, and suicidal ideation, whereas no associations were seen with non-suicidal self-injury after Holm-Bonferroni correction. In both groups, thoughts and behaviors concerning food and weight interfered significantly with daily life. DISCUSSION: SBED and BED were equally prevalent in this adolescent community sample, and similarly associated with indicators of poor mental health. The findings indicate that community adolescents reporting symptoms approximating clinical criteria of BED need intervention irrespectively of symptom frequency or duration. PUBLIC SIGNIFICANCE: This study adds knowledge to the field by comparing BED of low frequency and/or limited duration ("subthreshold BED," SBED) with full-syndrome BED in adolescents and showing that SBED in adolescence is both prevalent and associated with poor mental health to a similar extent as that of BED. Findings indicate that self-reported symptoms according to clinical criteria of SBED and BED alike constitute a public health problem and point to youngsters in need of intervention.

Prenatal antidepressant exposure and emotional disorders until age 22: a danish register study.

BACKGROUND: Selective serotonin reuptake inhibitors (SSRIs) are the most frequently prescribed antidepressants in pregnancy. Animal and some clinical studies have suggested potential increases in depression and anxiety following prenatal SSRI exposure, but the extent to which these are driven by the medication remains unclear. We used Danish population data to test associations between maternal SSRI use during pregnancy and children outcomes up to age 22. METHODS: We prospectively followed 1,094,202 single-birth Danish children born 1997-2015. The primary exposure was ≥ 1 SSRI prescription filled during pregnancy; the primary outcome, first diagnosis of a depressive, anxiety, or adjustment disorder, or redeemed prescription for an antidepressant medication. We used propensity score weights to adjust potential confounders, and incorporated data from the Danish National Birth Cohort (1997-2003) to further quantify potential residual confounding by subclinical factors. RESULTS: The final dataset included 15,651 exposed and 896,818 unexposed, children. After adjustments, SSRI-exposed had higher rates of the primary outcome than those of mothers who either did not use an SSRI (HR = 1.55 [95%CI:1.44,1.67] or discontinued the SSRI use ≥ 3 months prior to conception (HR = 1.23 [1.13,1.34]). Age of onset was earlier among exposed (9 [IQR:7-13] years) versus unexposed (12 [IQR:12-17] years) children (p < 0.01). Paternal SSRI use in the absence of maternal use during the index pregnancy (HR = 1.46 [1.35,1.58]) and maternal SSRI use only after pregnancy (HR = 1.42 [1.35,1.49]) were each also associated with these outcomes. CONCLUSIONS: While SSRI exposure was associated with increased risk in the children, this risk may be driven at least partly by underlying severity of maternal illness or other confounding factors.

Childhood body mass index and the subsequent risk of anorexia nervosa and bulimia nervosa among women: A large Danish population-based study.

OBJECTIVE: Evidence linking childhood body mass index (BMI) with subsequent eating disorders is equivocal. Potential explanations include different study populations and size, and that anorexia nervosa (AN) and bulimia nervosa (BN) should be studied separately. We examined whether birthweight and childhood BMI were associated with subsequent risk of AN and BN in girls. METHOD: We included 68,793 girls from the Copenhagen School Health Records Register born between 1960 and 1996 with information on birthweight and measured weights and heights obtained from school health examinations at ages 6-15 years. Diagnoses of AN and BN were retrieved from Danish nationwide patient registers. We used Cox proportional hazards regression to estimate hazard ratios (HRs) and 95% confidence intervals (CIs). RESULTS: We identified 355 cases of AN (median age: 19.0) and 273 cases of BN (median age: 21.8). Higher childhood BMI was linearly associated with decreasing risk of AN and increasing risk of BN at all childhood ages. At age 6, the HR for AN was 0.85 (95% CI: 0.74-0.97) per BMI z-score and the HR for BN was 1.78 (95% CI: 1.50-2.11) per BMI z-score. Birthweight >3.75 kg was associated with increased risk of BN compared to a birthweight of 3.26-3.75 kg. CONCLUSION: Higher BMI in girls at ages 6-15 years was associated with decreasing risk of AN and increasing risk of BN. Premorbid BMI could be relevant for the etiology of AN and BN, and in identifying high risk individuals. PUBLIC SIGNIFICANCE: Eating disorders are associated with elevated mortality, especially AN. Using a cohort of Copenhagen school children, we linked information on BMI at ages 6-15 years for 68,793 girls with nationwide patient registers. Low childhood BMI was associated with increased risk of AN, whereas high childhood BMI was associated with increased risk of BN. These findings may assist clinicians in identifying individuals at high-risk of these diseases.

Maternal alcohol consumption and the risk of miscarriage in the first and second trimesters: A systematic review and dose-response meta-analysis.

INTRODUCTION: According to a precautionary principle, it is recommended that pregnant women and women trying to conceive abstain from alcohol consumption. In this dose-response meta-analysis, we aimed to examine the association between alcohol consumption and binge drinking and the risk of miscarriage in the first and second trimesters. MATERIAL AND METHODS: The literature search was conducted in MEDLINE, Embase and the Cochrane Library in May 2022, without any language, geographic or time limitations. Cohort or case-control studies reporting dose-specific effects adjusting for maternal age and using separate risk assessments for first- and second-trimester miscarriages were included. Study quality was assessed using the Newcastle-Ottawa Scale. This study is registered with PROSPERO, registration number CRD42020221070. RESULTS: A total of 2124 articles were identified. Five articles met the inclusion criteria. Adjusted data from 153 619 women were included in the first-trimester analysis and data from 458 154 women in the second-trimester analysis. In the first and second trimesters, the risk of miscarriage increased by 7% (odds ratio [OR] 1.07, 95% confidence interval [CI] 0.96-1.20) and 3% (OR 1.03, 95% CI 0.99-1.08) for each additional drink per week, respectively, but not to a statistically significant degree. One article regarding binge drinking and the risk of miscarriage was found, which revealed no association between the variables in either the first or second trimester (OR 0.84 [95% CI 0.62-1.14] and OR 1.04 [95% CI 0.78-1.38]). CONCLUSIONS: This meta-analysis revealed no dose-dependent association between miscarriage risk and alcohol consumption, but further focused research is recommended. The research gap regarding miscarriage and binge drinking needs further investigation.

Correction: Gestational age at birth and body size from infancy through adolescence: An individual participant data meta-analysis on 253,810 singletons in 16 birth cohort studies.

[This corrects the article DOI: 10.1371/journal.pmed.1004036.].

Effectiveness of a community-based support programme to reduce social inequality in exclusive breastfeeding: study protocol for a cluster-randomised trial.

BACKGROUND: Breastmilk is the ideal nutrition for infants, and breastfeeding protects infants and mothers from a range of adverse health outcomes. In Denmark, most mothers initiate breastfeeding but many cease within the first months resulting in just 14% reaching the World Health Organization recommendation of six months of exclusive breastfeeding. Furthermore, the low breastfeeding proportion at six months is characterised by a marked social inequality. A previous intervention tested in a hospital setting succeeded in increasing the proportion of mothers breastfeeding exclusively at six months. However, most breastfeeding support is provided within the Danish municipality-based health visiting programme. Therefore, the intervention was adapted to fit the health visiting programme and implemented in 21 Danish municipalities. This article reports the study protocol, which will be used to evaluate the adapted intervention. METHODS: The intervention is tested in a cluster-randomised trial at the municipal level. A comprehensive evaluation approach is taken. The effectiveness of the intervention will be evaluated using survey and register data. Primary outcomes are the proportion of women who breastfeed exclusively at four months postpartum and duration of exclusive breastfeeding measured as a continuous outcome. A process evaluation will be completed to evaluate the implementation of the intervention; a realist evaluation will provide an understanding of the mechanisms of change characterising the intervention. Finally, a health economic evaluation will assess the cost-effectiveness and cost-utility of this complex intervention. DISCUSSION: This study protocol reports on the design and evaluation of the Breastfeeding Trial - a cluster-randomised trial implemented within the Danish Municipal Health Visiting Programme from April 2022 to October 2023. The purpose of the programme is to streamline breastfeeding support provided across healthcare sectors. The evaluation approach is comprehensive using a multitude of data to analyse the effect of the intervention and inform future efforts to improve breastfeeding for all. TRIAL REGISTRATION: Prospectively registered with Clinical Trials NCT05311631 https://clinicaltrials.gov/ct2/show/NCT05311631.

Maternal Tobacco Smoking During Pregnancy and Children's Emotional and Behavioral Trajectories: The EDEN Mother-Child Birth Cohort Study.

INTRODUCTION: The nature of the relationship between maternal tobacco smoking during pregnancy and the occurrence of children's behavioral problems is still a matter of controversy. We tested this association using data collected among a sample of pregnant women and their offspring followed up from birth to early adolescence (age 12 years), accounting for multiple parent, child, and family characteristics. AIMS AND METHODS: Data come from 1424 mother-child pairs participating in the Étude des Déterminants pré et post-natals précoces du développement psychomoteur et de la santé de l'ENfant mother-child cohort in France. Using repeated measures (3, 5.5, 8, and 11.5 years) of the mother-reported Strengths and Difficulties Questionnaire, we estimated trajectories of children's emotional and behavioral difficulties. Two aspects of maternal smoking were studied: The timing (nonsmoker, smoking during the periconceptional period, or throughout pregnancy) and the level of use (cigarettes/day) during the first trimester of pregnancy. Robust Poisson regression models controlled for confounding factors including maternal mental health and socioeconomic characteristics using propensity scores with the overlap weighting technique. RESULTS: Contrary to bivariate analyses, in propensity score-controlled regression models, maternal smoking throughout pregnancy was no longer significantly associated with offspring emotional or behavioral difficulties. Maternal heavy smoking (≥10 cigarettes/day) remained significantly associated with intermediate levels of conduct problems (RR 1.25, 95% CI 1.19 to 1.31). CONCLUSIONS: The association between maternal smoking in pregnancy and offspring's emotional and behavioral difficulties appears to be largely explained by women's other characteristics. However, maternal heavy smoking appears to be related to offspring behavioral difficulties beyond the role of confounding characteristics. IMPLICATIONS: The relationship between maternal smoking during pregnancy (in two modalities: Timing and level of smoking) and behavioral difficulties in children is still a matter of debate. While the relationship between any maternal tobacco use and offspring behavioral difficulties appears to be largely explained by confounding factors, heavy maternal smoking in the first trimester of pregnancy seems to be associated with offspring behavioral difficulties beyond the socioeconomic and mental health characteristics transmitted across generations.

Association of self-reported mother-infant relationship with child and adolescent mental health.

BACKGROUND: The quality of the relationship between mother and infant may have profound implications for the development of a child. Early indicators of psychological vulnerability may allow targeting of support for the child's cognitive, emotional and social development. A challenging mother-infant relationship could be one indicator of risk. AIMS: This study examined variations in psychological well-being and psychopathology among boys and girls according to early maternal perception of the mother-infant relationship. METHOD: This study is based on 64 663 mother-infant pairs from the Danish National Birth Cohort, for which data on the mother-infant relationship were collected at 6 months postpartum. Behavioural problems were assessed with the Danish version of the Strengths and Difficulties Questionnaire (SDQ) at child ages 7, 11 and 18 years, and we retrieved information on diagnosed childhood and adolescent psychiatric disorders and prescriptions of psychotropic drugs from Danish registries. RESULTS: Children in the challenging mother-infant relationship group had higher odds of behavioural problems at age 7 among both boys and girls. The same pattern of elevated estimates was identified for boys across all SDQ domains and for girls in three of five SDQ domains. All associations were attenuated at age 18, but increased odds of behavioural problems still existed. A challenging early mother-infant relationship increased the offspring's risk of being diagnosed with a psychiatric disorder or being prescribed a psychotropic drug before the age of 18. CONCLUSION: A challenging self-reported mother-infant relationship was associated with later psychopathological difficulties. Routine clinical enquiry may be useful in identification of future vulnerability.

Self-injury, suicidality and eating disorder symptoms in young adults following COVID-19 lockdowns in Denmark.

An aggravation in mental health during the COVID-19 lockdown has been suggested but the impact on self-injury, suicidality and eating disorders (EDs) are less elucidated. Using linear regression in different data set-ups that is longitudinal (n = 7,579) and repeated cross-sectional data (n = 24,625) from the Danish National Birth Cohort, we compared self-reported self-injury, suicidality and symptoms of EDs from before through different pandemic periods until spring 2021. The longitudinal data indicate a reduction in the proportion of self-injury in men (-3.2% points, 95% confidence interval (CI) = -4.3%; -2.2%, P < 0.001, d.f. = 2) and women (5.7% points, 95% CI = -6.6%; -4.8%, P < 0.001, d.f. = 2) and of suicide ideation in men (-3.0% points, 95% CI = -4.6%; -1.4%, P = 0.002, d.f. = 2) and women (-7.4% points, 95% CI = -8.7%; -6.0%, P < 0.001, d.f. = 2), as well as symptoms of EDs in women (-2.3% points, 95% CI = -3.2%; -1.4%, P < 0.001, d.f. = 2). For suicide attempt, indication of an increase was observed in men only (0.4% points, 95% CI = 0.1%; 0.7%, P = 0.019, d.f. = 2). In the repeated cross-sectional data, we observed no changes in any of the outcomes. Our findings provide no support for the increase in self-injury, suicidality and symptoms of EDs after the lockdowns. Key limitations are differential attrition and varying age in pre- and post-lockdown measures in the longitudinal data.