Constructing Causal Life-Course Models: Comparative Study of Data-Driven and Theory-Driven Approaches.

Life-course epidemiology relies on specifying complex (causal) models that describe how variables interplay over time. Traditionally, such models have been constructed by perusing existing theory and previous studies. By comparing data-driven and theory-driven models, we investigated whether data-driven causal discovery algorithms can help in this process. We focused on a longitudinal data set on a cohort of Danish men (the Metropolit Study, 1953-2017). The theory-driven models were constructed by 2 subject-field experts. The data-driven models were constructed by use of the temporal Peter-Clark (TPC) algorithm. The TPC algorithm utilizes the temporal information embedded in life-course data. We found that the data-driven models recovered some, but not all, causal relationships included in the theory-driven expert models. The data-driven method was especially good at identifying direct causal relationships that the experts had high confidence in. Moreover, in a post hoc assessment, we found that most of the direct causal relationships proposed by the data-driven model but not included in the theory-driven model were plausible. Thus, the data-driven model may propose additional meaningful causal hypotheses that are new or have been overlooked by the experts. In conclusion, data-driven methods can aid causal model construction in life-course epidemiology, and combining both data-driven and theory-driven methods can lead to even stronger models.

Effectiveness evaluation of an antenatal care intervention addressing disparities to improve perinatal outcomes in Denmark: A nationwide register-based analysis of a cluster randomised controlled trial (MAMAACT).

OBJECTIVE: To evaluate whether MAMAACT, an antenatal care (ANC) intervention, aimed at reducing ethnic and social disparities in perinatal mortality, affected perinatal health outcomes. DESIGN: Cluster randomised controlled trial. SETTING: Nineteen of 20 maternity wards in Denmark. POPULATION: All newborn children within a pre-implementation period (2014-2017) or an implementation period (2018-2019) (n = 188 658). INTERVENTION: A 6-h training session for midwives in intercultural communication and cultural competence, two follow-up dialogue meetings, and health education materials for pregnant women on warning signs of pregnancy complications in six languages. METHODS: Nationwide register-based analysis of the MAMAACT cluster randomised controlled trial. Mixed-effects logistic regression models were used to estimate the change in outcomes from pre- to post-implementation in the intervention group relative to the control group. Results were obtained for the overall study population and for children born to immigrants from low- to middle-income countries, separately. Models were adjusted for confounders selected a priori. MAIN OUTCOME MEASURES: A composite perinatal mortality and morbidity outcome, including stillbirths, neonatal deaths, Apgar score <7, umbilical arterial pH < 7.0, admissions to a neonatal intensive care unit (NICU) >48 h, and NICU admissions for mechanical ventilation. Additional outcomes were the individual measures. RESULTS: The intervention increased the risk of the composite outcome (adjusted odds ratio [aOR] 1.16, 95% confidence interval [CI] 0.99-1.34), mainly driven by differences in NICU admission risk (composite outcome excluding NICU, aOR 0.98, 95% CI 0.84-1.14). The intervention slightly increased the risk of low Apgar score and decreased the risk of low arterial pH, reflecting, however, small differences in absolute numbers. Other outcomes were unchanged. CONCLUSIONS: Overall, the MAMAACT intervention did not improve the composite perinatal mortality and morbidity outcome (when excluding NICU admissions). The lack of effects may be due to contextual factors including organisational barriers in ANC hindering the midwives from changing practices.

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.

Inflammatory human leucocyte antigen genotypes are not a risk factor in chronic subdural hematoma development.

BACKGROUND: Chronic subdural hematoma (CSDH) pathophysiology has undergone a paradigm shift from being regarded as solely traumatic to be driven mainly by inflammation. Human leucocyte antigen (HLA) is a gene complex involved in antigen processing and presentation to T lymphocytes, thereby mediating the adaptive immune responses. As specific HLA profiles are associated with inflammatory diseases, patients with a specific HLA profile may have a lower threshold for subdural inflammation, and therefore are predisposed for CSDH development. We hypothesized that (1) CSDH patients have a specific HLA profile compared to a Danish background population, and (2) patients with recurrent CSDH have a specific HLA profile compared to CSDH patients without recurrent CSDH. METHODS: Three specific HLA class II haplotypes known to drive inflammatory-mediated diseases were determined in 68 patients with CSDH. The distribution of these three haplotypes in our CSDH population was compared to a Danish population of blood donors using Monte Carlo Pearson's chi-square test. Furthermore, the distribution of the haplotypes was compared between CSDH patients with and without recurrent CSDH. RESULTS: We found no significant association between either of the haplotypes and the risk of CSDH, and neither of the haplotypes were associated with increased risk of CSDH recurrence. CONCLUSION: This study did not show an association between selected HLA class II haplotypes and the risk of CSDH or recurrence of CSDH compared with a healthy background population.

Causal inference for planning randomised critical care trials: Protocol for a scoping review.

BACKGROUND: Randomised clinical trials in critical care are prone to inconclusiveness owing, in part, to undue optimism about effect sizes and suboptimal accounting for heterogeneous treatment effects. Planned predictive enrichment based on secondary critical care data (often very rich with respect to both data types and temporal granularity) and causal inference methods may help overcome these challenges, but no overview exists about their use to this end. METHODS: We will conduct a scoping review to assess the extent and nature of the use of causal inference from secondary data for planned predictive enrichment of randomised clinical trials in critical care. We will systematically search 10 general and specialty journals for reports published on or after 1 January 2018, of randomised clinical trials enrolling adult critically ill patients. We will collect trial metadata (e.g., recruitment period and phase) and, when available, information pertaining to the focus of the review (predictive enrichment based on causal inference estimates from secondary data): causal inference methods, estimation techniques and software used; types of patient populations; data provenance, types and models; and the availability of the data (public or not). The results will be reported in a descriptive manner. DISCUSSION: The outlined scoping review aims to assess the use of causal inference methods and secondary data for planned predictive enrichment in randomised critical care trials. This will help guide methodological improvements to increase the utility, and facilitate the use, of causal inference estimates when planning such trials in the future.

Knowledge About How to Manage Warning Signs of Pregnancy Complications Among Immigrants and Their Descendants Compared to Women of Danish Origin.

OBJECTIVES: Ethnic differences in perinatal morbidity and mortality are starting points for social inequality in health. Increased incidence and severity of some pregnancy complications are found among immigrant women compared to ethnic majority women in high-income settings. However, little is known about immigrant women's assessment and management of warning signs. We aimed to assess women's knowledge about how to manage warning signs of pregnancy complications among immigrants and their descendants compared to women of Danish origin. METHODS: A cross-sectional study including phone-based interviews with 1899 women. Women were interviewed during gestational week 30-37 in one of six languages. Maternal ethnicity was categorized as; immigrants, their descendants and ethnic Danes. The outcomes were yes or no to; do you know what to do if you experience 1) sudden swelling, redness, and heat in one leg 2) severe headache and 3) vaginal bleeding. RESULTS: Immigrant women had lower levels of knowledge about how to manage all three types of warning signs of pregnancy complications compared to women of Danish origin. Adjusted OR for vaginal bleeding for women of European (4.33, 95% CI: 2.24-8.37), Asian (9.26, 95% CI: 5.10-16.83) and African (8.66, 95% CI: 3.26-23.05) origin. CONCLUSIONS FOR PRACTICE: Immigrant women had lower levels of knowledge about how to manage warning signs of pregnancy complications compared to women of Danish origin. Improved needs-based health education in pregnancy complications and body symptoms during antenatal care is needed to address delays in the management of complications and could potentially improve the health of women and children.

Pregnancy and post-partum tuberculosis; a nationwide register-based case-control study, Denmark, 1990 to 2018.

BackgroundPregnancy increases the risk of tuberculosis (TB), however, data on TB epidemiology in pregnant women are limited.AimTo guide possible interventions, we analysed risk factors for TB in pregnant and post-partum women.MethodsWe conducted a nationwide retrospective register-based case-control study from January 1990 to December 2018 in Denmark. Cases were women diagnosed with TB during their pregnancy or in the post-partum period. We selected two control groups: pregnant or post-partum women without TB, and non-pregnant women with TB. Differences were assessed by chi-squared or Fisher's exact test. Risk factors for TB were identified through logistic regression and estimated by odds ratio (OR).ResultsWe identified 392 cases, including 286 pregnant and 106 post-partum women. Most were migrants (n = 366; 93%) with a shorter median time spent in Denmark (2.74 years; interquartile range (IQR): 1.52-4.64) than non-pregnant TB controls (3.98 years; IQR: 1.43-8.51). Cases less likely had a Charlson comorbidity index ≥ 2compared with non-pregnant TB controls (p < 0.0001), and had no increased risk of severe disease (p = 0.847). Migrants from other World Health Organization regions than Europe, especially Africa (OR: 187; 95%CI: 125-281) had persistently higher odds of TB.ConclusionsIn Denmark, the risk of TB in pregnant and post-partum women is increased in migrant women who have stayed in the country a median time of approximately 3 years. We recommend increased focus on TB risk during pregnancy and suggest evaluating targeted TB screening of selected at-risk pregnant women to promote early case finding and prevent TB among mothers and their newborn children.

The role of parental education on the relationship between gestational age and school outcomes.

BACKGROUND: Individuals born preterm may experience difficulties beyond the neonatal period, such as poorer school outcomes. However, whether these outcomes are modified by family factors is less well-known. OBJECTIVES: To investigate whether parental educational level modify the relationship of gestational age with completion of final examinations and grade point average in compulsory education. METHODS: This nationwide register-based cohort study included singletons born in Denmark during 1995-2001. We investigated the differences in the associations between gestational age (24-44 weeks) and two school outcomes at 16 years according to parental educational level (lower (≤10 years), intermediate (11-13 years), and higher (>13 years)). Mixed-effect logistic regression and mixed-effect linear regression were used to model completion of final examination and grade point average, respectively. RESULTS: Of the 425 101 singletons, 4.7% were born before 37 weeks. The risk of not completing final examination increased with shorter gestational age and lower parental educational level. For instance, among adolescents whose parents had a lower educational level, the risk increased from 23.9% (95% CI, 23.1, 24.6) for those born in week 40 to 36.6% (95% CI, 31.5, 42.1) for those born in week 28. For adolescents whose parents had a higher educational level, the corresponding risk increase was 5.9% (95% CI, 5.7, 6.1) to 10.5% (95% CI, 8.6, 12.8), respectively. Grade point average decreased with shorter gestational age in adolescents born before 30 weeks and with lower parental educational level. The associations between gestational age and grade point average were similar across parental educational levels. For completions of final examination, the associations with gestational age were weaker with higher parental educational level. CONCLUSIONS: Shorter gestational age and lower parental educational level were associated with poorer school outcomes. Our findings suggest that parental educational level mitigates the adverse effects of shorter gestational age on some school outcomes.

Sequential rank agreement methods for comparison of ranked lists.

The comparison of alternative rankings of a set of items is a general and common task in applied statistics. Predictor variables are ranked according to magnitude of association with an outcome, prediction models rank subjects according to the personalized risk of an event, and genetic studies rank genes according to their difference in gene expression levels. We propose a sequential rank agreement measure to quantify the rank agreement among two or more ordered lists. This measure has an intuitive interpretation, it can be applied to any number of lists even if some are partially incomplete, and it provides information about the agreement along the lists. The sequential rank agreement can be evaluated analytically or be compared graphically to a permutation based reference set in order to identify changes in the list agreements. The usefulness of this measure is illustrated using gene rankings, and using data from two Danish ovarian cancer studies where we assess the within and between agreement of different statistical classification methods.

Structured exercise alters the gut microbiota in humans with overweight and obesity-A randomized controlled trial.

OBJECTIVES: Studies suggest that exercise affects the composition and function of the human gut microbiota, yet this has not been investigated in a randomized controlled trial. The primary aim of this study was to assess if exercise alters the diversity, composition and functional potential of the gut microbiota in free-living humans. A secondary aim was to test whether alpha diversity was associated with phenotypical outcomes. METHODS: Eighty eight participants with overweight or obesity completed a 6-month randomized controlled trial with 4 arms; habitual living (CON), active commuting by bike (BIKE) and leisure-time exercise of moderate (MOD) or vigorous intensity (VIG). Faecal samples for 16 s rRNA gene amplicon sequencing were collected prior to randomization and again after 3 and 6 months, with simultaneous registration of phenotypical outcomes and diet. RESULTS: Shannon's diversity index increased by 5% in VIG (CI95 1-9%, P = 0.012) at 3 months compared with CON. No associations were observed between alpha diversity and phenotypical outcomes. Beta diversity changed in all exercise groups compared with CON, particularly the participants in VIG showed decreased heterogeneity. No genera changed significantly. The inferred functional potential of the microbiota in the exercise groups was increased, primarily at 3 months and in MOD. CONCLUSION: Structured exercise induced subtle changes to the human gut microbiota. Cardiorespiratory fitness and fat mass were not associated with alpha diversity.

Physical exercise in the treatment of alcohol use disorder (AUD) patients affects their drinking habits: A randomized controlled trial.

AIM: The aim of this study is to compare the effect of exercise training on physical capacity and alcohol consumption in alcohol use disorder (AUD) patients. METHODS: One hundred and five AUD patients were randomly assigned to treatment as usual combined with running and brisk walking for 30-45 min twice a week, either in small supervised groups (GR) or individually (IND), or to a control group with no running (C). Assessments were made after 6 and 12 months of training. RESULTS: Training volume was estimated as 36 min per training bout at an intensity of 78% of HRmax with no differences between GR and IND ( p>.05). A highly significant reduction in training frequency was seen in both training groups after the first month ( p<.0001). Only IND increased VO2max, by 5.7% ( p<.05), while no differences were seen between GR, IND and C. Alcohol intake decreased from 219 to 41 units per 30 days as the average for the entire sample with no significant difference of drinking outcomes between groups ( p<.0001). CONCLUSIONS: We saw an effect on drinking habits after running in both groups. However, no additional effect was seen when compared with the control group. A drop in the training frequency during the intervention might have resulted in an insignificant training stimulus.

Community reinforcement and family training (CRAFT) - design of a cluster randomized controlled trial comparing individual, group and self-help interventions.

BACKGROUND: Around 585,000 people in Denmark engage in harmful use of alcohol with 140,000 suffering from outright alcohol dependence. The concerned significant others (CSOs) are affected by the drinking, often suffering almost as much as the person with alcohol use disorder. Community Reinforcement and Family Training (CRAFT) is aimed at CSOs who struggle unsuccessfully, in an effort to motivate their loved ones to stop drinking and seek treatment. The aims of this study are 1) To implement CRAFT interventions into the daily routine of operating Danish alcohol treatment centers 2) To investigate whether 6-week-individual CRAFT, 6-week-open group-based CRAFT or CRAFT based on self-help material, is efficient in getting problem drinkers to seek treatment for their alcohol problems 3) To investigate which of the three interventions (individual, group or self-directed CRAFT) is the most effective and in which group of population. METHODS: The study is a three-arm, cluster randomized controlled trial: A: individual CRAFT, group CRAFT, and CRAFT as a self-help intervention. A total of 405 concerned significant others to persons with alcohol abuse will be recruited from 24 alcohol outpatient clinics. The participants will fill out a questionnaire regarding i.e. life quality, if the drinking person entered treatment (main outcome) and satisfaction with the intervention, at baseline and after 3 and 6 months. DISCUSSION: We expect to establish evidence as to whether CRAFT is efficient in a Danish treatment setting and whether CRAFT is most effective at individual, group or self-help material only. TRIAL REGISTRATION: Clinical trials.gov ID: NCT03281057 . Registration date: September 13th, 2017.

The RESCueH Programme: Testing New Non-Pharmacologic Interventions for Alcohol Use Disorders: Rationale and Methods.

Excessive alcohol consumption is one of the most important lifestyle factors affecting the disease burden in the Western world. The results of treatment in daily practice are modest at best. The aim of the RESCueH programme is to develop and evaluate methods, which are as practice-near as possible, and therefore can be implemented quickly and easily in everyday clinical practice. It is the first clinical alcohol programme to be transatlantic in scope, with implementation in treatment centers located in Denmark, Germany and the US. The RESCueH programme comprises 5 randomized controlled trials, and the studies can be expected to result in (1) more patients starting treatment in specialized outpatient clinics, (2) a greater number of elderly patients being treated, (3) increased patient motivation for treatment and thus improved adherence, (4) more patients with stable positive outcomes after treatment and (5) fewer patients relapsing into harmful drinking. The aim of this paper is to discuss the rationale for the RESCueH programme, to present the studies and expected results.

Outpatient treatment of alcohol use disorders among subjects 60+ years: design of a randomized clinical trial conducted in three countries (Elderly Study).

BACKGROUND: The proportion of 60+ years with excessive alcohol intake varies in western countries between 6-16 % among men and 2-7 % among women. Specific events related to aging (e.g. loss of job, physical and mental capacity, or spouse) may contribute to onset or continuation of alcohol use disorders (AUD). We present the rationale and design of a multisite, multinational AUD treatment study for subjects aged 60+ years. METHODS/DESIGN: 1,000 subjects seeking treatment for AUD according to DSM-5 in outpatient clinics in Denmark, Germany, and New Mexico (USA) are invited to participate in a RCT. Participants are randomly assigned to four sessions of Motivational Enhancement Treatment (MET) or to MET plus an add-on with eight sessions based on the Community Reinforcement Approach (CRA), which include a new module targeting specific problems of older adults. A series of assessment instruments is applied, including the Form-90, Alcohol Dependence Scale, Penn Alcohol Craving Scale, Brief Symptom Inventory and WHO Quality of Life. Enrolment will be completed by April 2016 and data collection by April 2017. The primary outcome is the proportion in each group who are abstinent or have a controlled use of alcohol six months after treatment initiation. Controlled use is defined as maximum blood alcohol content not exceeding 0.05 % during the last month. Total abstinence is a secondary outcome, together with quality of life andcompliance with treatment. DISCUSSION: The study will provide new knowledge about brief treatment of AUD for older subjects. As the treatment is manualized and applied in routine treatment facilities, barriers for implementation in the health care system are relatively low. Finally, as the study is being conducted in three different countries it will also provide significant insight into the possible interaction of service system differences and related patient characteristics in predictionof treatment outcome. TRIAL REGISTRATION: Clinical Trials.gov NCT02084173 , March 7, 2014.

Statistical models for assessing agreement for quantitative data with heterogeneous random raters and replicate measurements.

Agreement between methods for quantitative measurements are typically assessed by computing limits of agreement between pairs of methods and/or by illustration through Bland-Altman plots. We consider the situation where the observed measurement methods are considered a random sample from a population of possible methods, and discuss how the underlying linear mixed effects model can be extended to this situation. This is relevant when, for example, the methods represent raters/judges that are used to score specific individuals or items. In the case of random methods, we are not interested in estimates pertaining to the specific methods, but are instead interested in quantifying the variation between the methods actually involved making measurements, and accommodating this as an extra source of variation when generalizing to the clinical performance of a method. In the model we allow raters to have individual precision/skill and permit linked replicates (i.e., when the numbering, labeling or ordering of the replicates within items is important). Applications involving estimation of the limits of agreement for two datasets are shown: A dataset of spatial perception among a group of students as well as a dataset on consumer preference of French chocolate. The models are implemented in the MethComp package for R [Carstensen B, Gurrin L, Ekstrøm CT, Figurski M. MethComp: functions for analysis of agreement in method comparison studies; 2013. R package version 1.22, R Core Team. R: a language and environment for statistical computing. Vienna, Austria: R Foundation for Statistical Computing; 2012].

Joint regression analysis of multiple traits based on genetic relationships.

Motivation: Polygenic scores (PGSs) are widely available and employed in genomic data analyses for predicting and understanding genetic architectures. Existing approaches either require information on SNP level, do not infer clusters of traits sharing genetic characteristic, or do not have any immediate predictive properties. Results: Here, we present geneJAM, which is a novel clustering and estimation method using PGSs for inferring a genetic relationship among multiple, simultaneously measured and potentially correlated traits in a multivariate GWAS.Using graphical lasso, we estimate a sparse covariance matrix of the PGSs and obtain clusters of traits sharing genetic characteristics. We use the clusters to specify the structure of the error covariance matrix of a generalized least squares (GLS) model and use the feasible GLS estimator for estimating a linear regression model with a certain unknown degree of correlation between the residuals.The method suits many biology studies well with traits embedded in some genetic functioning groups and facilitates development of the PGS research. We compare the method with fully parametric techniques on simulated data and illustrate the utility of the methods by examining a heterogeneous stock mouse data set from the Wellcome Trust Centre for Human Genetics. We demonstrate that the method successfully identifies clusters of traits and increases precision, power, and computational efficiency. Availability and implementation: GeneJAM is implemented in R and available at: https://github.com/abuchardt/geneJAM.

The causal effect of early retirement on medication use across sex and occupation: evidence from Danish administrative data.

We examine the causal effect of early retirement on medication use using Danish registry data. A reform in early retirement schemes in 2006 gradually increased eligibility ages from 60 to 64 differentially across birth cohorts. This enables an instrumental variable design that was applied using novel g-estimation methods that alleviate bias in binary outcome IV models. Our data allow studying patterns in the short run (ages 59½-60½) and in the long run (ages 57-63). For those who were eligible already at age 60, retirement did not change overall medication use. However, when investigating medication and population subgroups, we see that painkiller use decreases and hypertension medication as well as mental health medication use increase after retirement in almost all population subgroups. Moreover, males as well as the blue-collar occupation subgroups do show decreases in overall medication use after early retirement. In conclusion, our analyses reveal that retirement can have important heterogeneous health effects across population groups and are potentially informative about the welfare benefits of social insurance more broadly.

Unlocking the mechanisms of change in the MAMAACT intervention to reduce ethnic disparity in stillbirth and newborns' health: integration of evaluation findings.

Ethnic disparities in stillbirth exist in Europe and suboptimal care due to miscommunication is one contributing cause. The MAMAACT intervention aimed to reduce ethnic disparity in stillbirth and newborns' health through improved management of pregnancy complications. The intervention encompassed training of antenatal care midwives in cultural competencies and intercultural communication combined with health education materials for the expecting parents about symptoms of pregnancy complications. The evaluation consisted of a qualitative in-depth implementation analysis and a process evaluation embedded in a cluster randomized trial including 19 of 20 maternity wards in Denmark. In this article, the findings from the different evaluation perspectives are integrated. The integration follows the principles of realist evaluation by analyzing to what extent the MAMAACT activities were generating mechanisms of change in interaction with the context. The integration analysis shows that the health education materials in the MAMAACT intervention contributed to heightened health literacy concerning pregnancy complications among pregnant women. Additionally, the training of midwives in cultural competency and intercultural communication raised awareness among midwives. Nonetheless, the exclusive emphasis on midwives and the inflexibility in care provision hindered them from changing their communication practices. To enhance the cultural competence in maternity care, it is essential to implement more comprehensive initiatives involving healthcare professionals in maternity care at all levels, from pregraduate to postgraduate. Adequate interpreter services and management support should also be ensured. Currently, the Danish antenatal care system faces challenges including inadequate information transfer between healthcare sectors, insufficient differentiation of care, and inflexibility in midwife scheduling. This results in a lack of responsiveness to the individual needs of women with immigrant backgrounds, potentially reproducing health inequities.

Discovering Subgroups of Children With High Mortality in Urban Guinea-Bissau: Exploratory and Validation Cohort Study.

BACKGROUND: The decline in global child mortality is an important public health achievement, yet child mortality remains disproportionally high in many low-income countries like Guinea-Bissau. The persisting high mortality rates necessitate targeted research to identify vulnerable subgroups of children and formulate effective interventions. OBJECTIVE: This study aimed to discover subgroups of children at an elevated risk of mortality in the urban setting of Bissau, Guinea-Bissau, West Africa. By identifying these groups, we intend to provide a foundation for developing targeted health interventions and inform public health policy. METHODS: We used data from the health and demographic surveillance site, Bandim Health Project, covering 2003 to 2019. We identified baseline variables recorded before children reached the age of 6 weeks. The focus was on determining factors consistently linked with increased mortality up to the age of 3 years. Our multifaceted methodological approach incorporated spatial analysis for visualizing geographical variations in mortality risk, causally adjusted regression analysis to single out specific risk factors, and machine learning techniques for identifying clusters of multifactorial risk factors. To ensure robustness and validity, we divided the data set temporally, assessing the persistence of identified subgroups over different periods. The reassessment of mortality risk used the targeted maximum likelihood estimation (TMLE) method to achieve more robust causal modeling. RESULTS: We analyzed data from 21,005 children. The mortality risk (6 weeks to 3 years of age) was 5.2% (95% CI 4.8%-5.6%) for children born between 2003 and 2011, and 2.9% (95% CI 2.5%-3.3%) for children born between 2012 and 2016. Our findings revealed 3 distinct high-risk subgroups with notably higher mortality rates, children residing in a specific urban area (adjusted mortality risk difference of 3.4%, 95% CI 0.3%-6.5%), children born to mothers with no prenatal consultations (adjusted mortality risk difference of 5.8%, 95% CI 2.6%-8.9%), and children from polygamous families born during the dry season (adjusted mortality risk difference of 1.7%, 95% CI 0.4%-2.9%). These subgroups, though small, showed a consistent pattern of higher mortality risk over time. Common social and economic factors were linked to a larger share of the total child deaths. CONCLUSIONS: The study's results underscore the need for targeted interventions to address the specific risks faced by these identified high-risk subgroups. These interventions should be designed to work to complement broader public health strategies, creating a comprehensive approach to reducing child mortality. We suggest future research that focuses on developing, testing, and comparing targeted intervention strategies unraveling the proposed hypotheses found in this study. The ultimate aim is to optimize health outcomes for all children in high-mortality settings, leveraging a strategic mix of targeted and general health interventions to address the varied needs of different child subgroups.