Twin Research and Human Genetics

Background: Forming an equal attachment relationship with more than one child at a time can be challenging for parents. The risks associated with multiple pregnancies for the expecting parent and fetuses can adversely affect the entire pregnancy and influence the early interaction between the woman and the baby. The purpose of this empirical study was to describe from the perspective of women which factors promote and weaken early interaction in multiple pregnancies. Methods: Data collection was conducted remotely through semistructured individual interviews, in collaboration with a regional welfare agency and multiple birth family associations. A total of 11 women expecting twins voluntarily participated in the interviews. The qualitative data were analysed via inductive content analysis. Results Factors that strengthened early maternal-fetal interaction included considering the fetus and fetuses as part of the family during pregnancy, naming the fetuses individually, and using terms other than "fetus." Strong social support and parents' understanding of fetal awareness and reciprocity also significantly promoted early interaction. Conversely, early knowledge of expecting twins, insufficient guidance from healthcare professionals for the formation of early interactions, unequal attachment to fetuses, a lack of knowledge, and fears weakened early interactions. Conclusions: Our findings suggest that early interaction and guidance should be initiated as soon as parents learn that they expect more than one child. Throughout prenatal visits, there should be a focus on supporting the resources of pregnant women and their families to enhance maternal capabilities. Keywords: early interaction, maternal-fetal attachment, multiple pregnancy, twins, qualitative study

Background: Maternal obesity is associated with lower breastfeeding initiation, shorter breastfeeding duration and lower rates of exclusive breastfeeding. Although breastfeeding intention predicts initiation, little is known about how first-time mothers living with obesity experience the transition from antenatal intention to postpartum reality. Aim: This qualitative study explored breastfeeding expectations, intentions, attitudes and early breastfeeding challenges among first-time mothers living with obesity in Switzerland. Methods: Seven semi-structured interviews were conducted with first-time mothers living with obesity in German-speaking Switzerland. Interviews were audio-recorded, transcribed verbatim and analysed using reflexive thematic analysis according to Braun and Clarke. Results: All participants intended to breastfeed and described breastfeeding as part of motherhood. However, most experienced a postpartum reality that differed from their expectations. Three themes were developed: antenatal engagement with and expectations of breastfeeding, postpartum breastfeeding reality, and everyday breastfeeding life. Women received little antenatal breastfeeding counselling and faced challenges related to medicalised birth, delayed lactogenesis II, breast anatomy, pain, insufficient milk supply, pumping and inconsistent professional support. Several women described feelings of failure when breastfeeding did not work as hoped. Conclusion: First-time mothers living with obesity may have strong breastfeeding intentions but still experience major challenges after birth. Breastfeeding support should start during pregnancy and be realistic, respectful and weight-inclusive.

Background: Poor prenatal sleep health is associated with greater gestational weight gain, but the contributions to longer-term maternal weight retention remain unclear. Purpose: To examine associations between prenatal sleep health across multiple domains and maternal weight retention 2 to 7 years after a first birth. Methods: Participants were from the nuMoM2b-Heart Health Study. Self-reported sleep was assessed during early (6 to 13 6/7 weeks) and mid-pregnancy (22 to 28 6/7 weeks) across six domains: regularity, quality, sleepiness, timing, efficiency, and duration. A multidimensional sleep health (MSH) score reflected the number of domains meeting healthy thresholds. Outcomes included maternal weight retention, total and substantial (>11 lbs.), from pre-pregnancy to 2 to 7 years after a first birth. Associations were estimated using adjusted linear regression for total weight retention and Poisson regression with robust variance for substantial weight retention. Results: The sample included 3,661 individuals with data in early (n = 2,962) and mid-pregnancy (n = 3,210). In early pregnancy, healthy sleep duration was associated with lower total weight retention, whereas healthy sleep regularity was unexpectedly associated with greater retention. In contrast, during mid-pregnancy, a higher MSH score was associated with a lower risk of substantial weight retention (RR = 0.96, 95% CI: 0.93 to 0.99). Healthy sleep duration and quality were the two individual domains associated with lower weight retention (2 to 3 lbs.). Conclusions: In a prospective cohort of pregnant nulliparous individuals, healthy prenatal sleep, particularly during mid-pregnancy, was associated with less maternal weight retention 2 to 7 years after delivery. Future studies should estimate the causal effects of sleep health on long-term maternal weight retention.

Breastfeeding grief is a form of complicated and disenfranchised grief which occurs when mothers are unable to achieve their breastfeeding goals; it is characterized by profound sadness and a sense of failure that negatively impact perinatal mental health. The scientific literature consists of very few studies on breastfeeding grief; and a critical gap remains about the primary concern of mothers experiencing breastfeeding grief and how these mothers cope with this concern. This study includes the first substantive grounded theory of breastfeeding grief using a classic grounded theory design. A purposive sample of 46 mothers who are experiencing/have experienced breastfeeding grief completed unstructured virtual individual interviews, and an additional theoretical sample of 19 mothers completed semi-structured individual interviews. Interviews were transcribed verbatim and coded in Quirkos. Data were analyzed using constant comparative analysis, which resulted in the development of a substantive grounded theory. The theory has 3 postulations: 1) the main concern of mothers experiencing breastfeeding is unattained perception of motherhood, 2) the basic psychosocial process used to cope with unattained perception of motherhood is reconciling motherhood ideology, which occurs in 5 stages (responding to disruptions, disavowing reality, grieving, accepting reality, and reframing motherhood ideology), and 3) factors accounting for variation in reconciling motherhood include self-worth, personality, social sentiment/norm, context, and conditions. This theory underscores breastfeeding grief as indeed a perinatal mental health concern, that transcends affective, cognitive, and psychomotor domains. Movement across the stages of reconciling breastfeeding grief is cyclical, not progressive. Therefore, focused psychological interventions to address this concern are urgently warranted.

Abstract Aim: To translate, culturally adapt, and psychometrically validate the Arabic version of the REAP-S among Arabic speaking young adults using Confirmatory Factor Analysis (CFA) and Rasch Measurement Theory (RMT). Design: A cross-sectional methodological psychometric validation study. Methods: The study included 500 undergraduate and postgraduate nursing students recruited from Saudi universities during the 2025-2026 academic year. The REAP-S was translated into Arabic using standardized forward backward translation procedures and cross-cultural adaptation guidelines. Participants completed the Arabic REAP-S through an online self-administered questionnaire. Construct validity was evaluated using CFA with robust estimators, assessing the Comparative Fit Index (CFI), Tucker-Lewis Index (TLI), Root Mean Square Error of Approximation (RMSEA), and Standardized Root Mean Square Residual (SRMR). Rasch Measurement Theory was applied to examine item fit, response category functioning, person item targeting, and person reliability. We assessed internal consistency using Cronbach's alpha and the Rasch Person Separation Index (PSI). Results: Psychometric analyses included 490 participants with a median age of 20 years (IQR = 19-22), of whom 54.1% were female. CFA supported the hypothesized one-factor structure and showed good model fit (CFI = 0.984, TLI = 0.978, RMSEA = 0.076, SRMR = 0.061). Standardized factor loadings ranged from 0.429 to 0.768, and internal consistency was good (Cronbach's = 0.863). Rasch analysis confirmed the scale's unidimensionality, with satisfactory person reliability (Expected A Posteriori [EAP] = 0.872; Weighted Likelihood Estimate [WLE] = 0.848). All items demonstrated acceptable infit and outfit mean square statistics (0.826-1.311 and 0.866-1.283, respectively), with ordered response thresholds and adequate person-item targeting. Overall, the Arabic REAP-S effectively discriminated between different levels of dietary behavior among Arabic-speaking young adults. Conclusion: The Arabic REAP-S demonstrated strong validity and reliability, supporting its unidimensional structure and appropriate psychometric performance. Evidence from both CFA and Rasch analysis confirmed acceptable model fit, good internal consistency, and adequate item functioning. The instrument provides a brief and practical tool for assessing dietary behaviors among Arabic-speaking young adults in clinical and research settings. Implications for the Profession and/or Patient Care: The Arabic REAP-S provides nurses and other healthcare professionals with a brief, standardized tool for rapidly assessing dietary behaviors and identifying individuals at nutritional risk. Its integration into routine clinical and community practice may support early dietary screening, guide nutrition education, and strengthen evidence based preventive care for diet related chronic diseases. Keywords: Arabic REAP-S; Dietary Screening; Confirmatory Factor Analysis; Rasch Measurement Theory; Construct Validity; Young Adults.

Background: Stress research in nursing education has largely focused on distress, stressors, and negative outcomes, although challenging experiences may also support motivation, confidence, learning, and growth when appraised positively. Objective: To develop and evaluate the psychometric properties of the Nursing Student Positive Stress Scale (NSPSS). Design: A methodological instrument development and psychometric evaluation study. Methods: The NSPSS was developed using a deductive, theory-driven approach informed by the transactional theory of stress and coping and positive psychology perspectives. Content validity was assessed by an international nursing expert panel. Psychometric evaluation used national survey data from nursing students in New Zealand. Of 539 responses, 507 were analysed. Exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) were conducted using separate subsamples. Internal consistency was assessed using Cronbach's alpha and McDonald's omega, and convergent validity through correlation with Perceived Stress Scale-10 scores. Results: Content validity was strong (I-CVI = .88-1.00; S-CVI/Ave = .975; S-CVI/UA = .800). EFA identified a dominant factor explaining 41.38% of variance (loadings = .528-.735). CFA supported a two-context Academic and Clinical Positive Stress model with correlated residuals between five parallel item pairs, chi-square(29) = 60.49, CFI = .970, TLI = .954, RMSEA = .063, SRMR = .065. Internal consistency was good (alpha = .839; omega = .843). NSPSS scores correlated negatively with PSS-10 scores (r = -.298, p < .001). Conclusion: The NSPSS demonstrated strong content validity, preliminary evidence of structural and convergent validity, and good internal consistency reliability for assessing positive stress appraisal among nursing students. Further validation in independent samples is warranted.

Background: Cardiometabolic health typically declines with age and is worse among individuals living with obesity. Weight loss medications have modified the potential for weight loss across the life course, but it remains unclear whether weight reduction in later midlife contributes to improved cardiometabolic health, or if continuing to gain weight may continue to worsen cardiometabolic health. Methods: Using the nationally representative 1958 National Child Development Study (NCDS), a British birth cohort, associations were examined using lagged linear regression between weight change between ages 50-55 and health outcomes at age 62 (n=6,309 high-density lipoprotein (HDLc) and low-density lipoprotein (LDLc) cholesterol, systolic and diastolic blood pressure (SBP and DBP), heart rate, triglycerides, C-reactive protein (CRP), and glycated haemoglobin (HbA1c). Models accounted for prior biomarker levels at age 44. We also explored impacts of weight change on subsequent body composition. Results: Those who gained weight into or within obesity had less favourable cardiometabolic profiles and experienced faster deterioration of cardiometabolic markers between the ages of 44 and 62 than those remaining in healthy weight (e.g. SBP: 5.726, 95% CI: 2.660 to 8.793, p < 0.001; CRP: 0.802, 95% CI: 0.409 to 1.196, p < 0.001). Those who lost weight from obesity had similar rates of cardiometabolic biomarker deterioration to the healthy weight group (SBP: 0.947, 95%CI: -6.605 to 8.499, p=0.806; CRP: 0.140, 95% CI: -0.774 to 1.055, p= 0.764). Conclusion: Weight change in midlife tends towards increasing obesity and associated adverse cardiometabolic risk. Those who lose weight experienced improved cardiometabolic profiles. By viewing midlife as a modifiable stage of the life course, this study highlights opportunities to promote cardiometabolic health, and limit the speed of health decline.

Background. DNA methylation patterns in cord blood are robustly associated with birthweight in the general population. However, it remains unknown whether these associations extend to clinically relevant populations, such as preterm neonates or those born small for gestational age, and whether they directly reflect birthweight or are driven indirectly by genetic, familial, maternal, and obstetric factors. Methods. We calculated a birthweight methylation profile score (MPSBW) using weights of 835 CpGs previously associated with birthweight in the general population and evaluated its association with birthweight in 67 monochorionic (MC) twin pairs including 134 neonates (97% born preterm) from the Twinlife study. MC twin pairs are identical twins sharing a single placenta, often unequally, which can result in unequal resource distribution and differential fetal growth. Results. We examined the association between within-pair differences in birthweight and MPSBW, thereby estimating the association independent of factors shared equally by co-twins. A 500-gram increase in birthweight was associated with a 0.256 SD increase in MPSBW (p<0.005) in this population of preterm neonates. Adjustment for polygenic score for birthweight (PGSBW) confirmed that the observed epigenetic associations were not driven by common genetic variation underlying birthweight. Interestingly, a similar effect size (0.226 SD per 500 g birthweight increase; p<0.05) was observed in the within-pair analysis, which controls for all shared influences within a twin pair. Conclusion DNA methylation is associated with individual differences in birthweight in a high-risk clinical population of MC twins, independent of shared genetic, familial or maternal influences.

Background Licensed registered nurses (RNs) who are not employed in nursing are often counted as reserve capacity. A license, however, does not indicate readiness to enter the workforce. We examined whether this population contains distinct workforce activation states and how reported reasons for not working in nursing correspond to those states. Methods We analyzed the 2022 National Sample Survey of Registered Nurses, a nationally representative cross-sectional survey of licensed US nurses. The study population comprised RNs and RN advanced practice registered nurses who were actively licensed but not working for pay in nursing on 31 December 2021. The outcome distinguished five states reported at survey response: no future intention, actively looking, plans future entry or return, undecided, and already entered or returned. Ten prespecified reasons with adequate cell sizes were examined in separate survey-weighted multinomial models. Variance estimation used the main survey weight and 80 successive difference replicate weights. Models adjusted for age, sex, race and ethnicity, nursing education and license type; the family caregiving model also adjusted for marital status and dependents. Results The model-eligible sample included 7,744 respondents, representing 869,236 licensed RNs. An estimated 44.4% had no future intention to work in nursing, 25.6% were undecided, 14.6% had entered or returned, 10.7% planned future entry or return, and 4.7% were actively looking. Retirement was associated with a 27.0 percentage point higher adjusted probability of no future intention (95% CI 21.1 to 32.9). Family caregiving was associated with a 14.6 point higher probability of planned entry or return (95% CI 10.9 to 18.3) and a 13.3-point lower probability of no future intention (95% CI -18.0 to -8.5). Burnout, stressful work, inadequate staffing, scheduling problems and poor management were each concentrated in the undecided state, with adjusted probability differences from 6.1 to 14.6 points. These patterns remained in analyses restricted by retirement, prior nursing work, license type and official imputation status. Conclusions The licensed nonworking RN population is a stratified labor reserve. Family caregiving identifies a planned reserve, workplace barriers identify a conditional reserve, and retirement identifies a largely nonmobilizable group. Workforce planning should measure activation state before treating licensed capacity as available supply.

Abstract Background: Hospital discharge from coronary care units (CCUs) is commonly framed as a discrete clinical or administrative endpoint. This event-based conceptualisation obscures the ongoing nursing and interprofessional work undertaken across the admission to stabilise discharge readiness. Aim: To theorise discharge readiness in CCUs as anticipatory nursing and interprofessional work and to examine how professional roles, organisational systems and service contexts shape discharge across two national context. Design: Qualitative study utilising reflexive thematic analysis. Methods: Semi-structured interviews and focus groups were conducted with 37 clinicians (nurses, allied health professionals and medical staff) working in CCUs in Australia and the United Kingdom. Reflexive Thematic Analysis was undertaken inductively within each dataset, followed by higher-level interpretive integration. Results: Four interrelated themes conceptualised discharge readiness as: (1) anticipatory nursing work initiated at admission and sustained through ongoing assessment, coordination and documentation; (2) negotiated readiness achieved through interprofessional alignment and distributed expertise; (3) discharge documentation as a site of organisational tension shaping workflow and communication; and (4) discharge flow constrained by system-level pressures, downstream service availability and policy logics. Across both national contexts, nurses were positioned as custodians of discharge readiness through continuous monitoring, relational coordination and informal risk management, although enactment varied by organisational setting. Conclusion: This study contributes to nursing scholarship by positioning discharge readiness not as a single decision point, but as an emergent outcome of anticipatory nursing labour, interprofessional negotiation and organisational systems. By making visible the distributed and often hidden work underpinning discharge, the findings extend existing models of transitional care and provide a theoretically grounded foundation for strengthening discharge practice in coronary care nursing.

Objective: Overweight and obesity in childhood and adolescence are major risk factors for health problems across the lifespan. This manuscript reports the current prevalence of overweight and obesity among children and adolescents aged 4-17years living in Germany and compares them with previous population-based results. Methods: A representative, cross-sectional sample of 4-17-year-olds was drawn following a multistage sampling process. Analyses are based on weight and height of 3,978 individuals measured in the field by trained test instructors between 2023-2025. Overweight and obesity classification was defined using age- and sex-specific body-mass-index percentiles. To allow for comparability of prevalence estimates derived from previous assessment waves and other panel studies dating back to 2005, an alignment factor was derived using an inverse probability of participation weighting approach. Together with sampling weights, the alignment factor was applied to obtain current, representative prevalence estimates of overweight and obesity. Results: The aligned, weighted prevalence of overweight and obesity was 16.1% (95%CI[14.5-17.9%]), whereas prevalence of obesity was 6.7% (95%CI [5.5-8.1%]). Age- and sex-specific prevalence rates are reported and compared to previous waves. Conclusions: The current prevalence of overweight and obesity in children and adolescents aged 4-17 years living in Germany remains stable over the past two decades.

Purpose: Impaired balance and fall risk in individuals with respiratory conditions highlight the importance of respiratory-postural integration during upright activity. However, breathing and postural control are often studied separately, limiting understanding of their interaction. Singing imposes concurrent ventilatory and trunk control demands, yet respiratory-postural responses during standing singing remain unclear. We examined the effects of vocalisation and tempo on respiratory-postural responses during standing, and whether age and singing experience moderated these responses. Methods: Eighty healthy younger (18-35yr; n=35) and older ([&ge;]60yr; n= 45) adults completed rhythmically paced speaking and singing tasks at slow, normal, and fast tempos while standing on a force platform. Respiratory rate (RR), mediolateral and anteroposterior sway, peripheral oxygen saturation, and perceived breathlessness were measured. Generalised estimating equations assessed vocalisation, tempo, and their interaction, with moderation by age and singing experience. Results: RR showed a vocalisation x tempo interaction (p<.001), with higher RR during slow speaking and greatest increases during fast singing. Singing increased postural sway relative to speaking, particularly mediolaterally (p<.001), with tempo-related increases in anteroposterior sway (p<.001). Older adults exhibited greater postural sway overall (p values[&le;].040) but similar task-dependent modulation to younger adults. Singing experience attenuated RR increases during fast singing (p=.033) and was associated with greater mediolateral sway (p=.004). Perceived breathlessness increased with tempo but was not associated with vocalisation; SpO2 was unchanged. Conclusions: Standing singing was associated with tempo-dependent respiratory and postural responses. Age and singing experience showed distinct associations with these responses. Task-dependent respiratory-postural coordination appeared preserved among participants.

Parental genotypes may influence offspring outcomes through the environments parents provide, a process known as genetic nurture, but estimating such effects from polygenic scores is complicated jointly by measurement error, unobserved genetic variation, and assortative mating. Here, we introduce RAVEL, a structural equation modeling framework that uses two independently constructed polygenic scores for the same trait to estimate latent genetic liability associations in parent-offspring trios and to distinguish direct and non-transmitted genetic associations. Through analytic derivations and simulations, we show that naive trio regressions can produce spurious non-zero parental coefficients, attenuate genuine genetic nurture effects, and obscure asymmetric parental effects, whereas RAVEL recovers unbiased estimates of the underlying coefficients when the assortative mating history and the extent of unobserved genetic variation are correctly specified. Applying RAVEL to national test scores in the Norwegian Mother, Father and Child Cohort Study using polygenic scores for educational attainment, we find that parental genetic liabilities explain less than 0.5% as much variance in childhood cognitive performance as the child's own genetic liability (substantially lower than the 10% observed with naive trio regressions) once assortative mating is modeled, with only a small paternal association significantly surviving the correction. In contrast, we find a maternal-specific non-transmitted association with offspring premature birth. RAVEL provides a general framework for interpreting trio polygenic score analyses of direct and non-transmitted genetic effects, clarifying the contribution of parental genetic liabilities to offspring traits.

Importance. Anorexia nervosa (AN) is a severe metabo-psychiatric disorder with heterogeneous outcomes and elevated mortality. Characterizing severity trajectories may improve early risk stratification and targeted intervention. Objective. To identify AN severity trajectories using a register-based severity index (AN-RSI) and examine their associations with polygenic scores (PGS), preceding (prior to AN diagnosis) as well as subsequent (5 years post AN diagnosis) psychiatric and somatic disorders. Design. Population-based cohort study. Setting. Nationwide study in Denmark. Participants. Individuals born between 1969 and 2013 with diagnosed AN (N = 9,534 individuals). Genetic data were available in a subsample comprising 5,126 individuals. Exposures. Forty-one PGS indexing traits relevant to AN, and psychiatric and somatic disorders prior to AN diagnosis. Main Outcomes and Measures. The main outcomes of interest were the AN-RSI trajectories and psychiatric and somatic disorders 5 years post AN diagnosis. Results. Three trajectories were identified: "low and stable" (32.6%), "medium and stable" (53.5%), and "high increasing" (14.0%). The "low and stable" group was used as the comparison group for all analyses. Each 1 standard deviation (SD) increase in AN PGS corresponded with 13% greater odds of following the "high increasing" trajectory. Increases in BMI and attention-deficit/hyperactivity disorder PGS corresponded with 15% and 14% lower odds of following the "high increasing" trajectory, respectively. No preceding psychiatric or somatic disorders were significantly associated with trajectory assignment. In contrast, psychiatric and somatic disorders were more likely to occur subsequent to an AN diagnosis in those in the "high increasing" trajectory with odds ratios (OR) ranging between 1.73 and 3.81 for psychiatric disorders and between 1.61 and 5.38 for somatic disorders with a notable exception of obesity which showed a lower OR of 0.27. Conclusions and Relevance. Our findings hold significant clinical relevance by demonstrating that individuals with AN follow distinct severity trajectories that have different genetic risk as measured by PGS and clear differences in post-diagnosis morbidity patterns but no discernable differences in pre-diagnosis psychiatric or somatic morbidity. As the eating disorders genetics field progresses, incorporating PGS into comprehensive assessments at first presentation may aid in early identification, personalized intervention, and resource allocation for individuals at higher risk of developing a severe illness trajectory.

Introduction: Nursing students experience stress arising from demanding academic requirements and emotionally challenging clinical placements, which may affect wellbeing, learning, and programme retention. This study explored perceptions of stress, its impacts, and coping experiences within undergraduate nursing education among nursing students and educators in New Zealand. Methods: A qualitative descriptive study was conducted with six undergraduate nursing students and six nurse educators at a New Zealand university. Data were collected through semi-structured interviews and analysed using inductive reflexive thematic analysis, with interpretation informed by the Transactional Model of Stress and Coping. Results: Three themes were identified: stress from multiple sources, stress shaping wellbeing and learning, and navigating stress through appraisal and coping. Stress arose from academic, clinical, personal, and social demands and affected academic engagement, health, and relationships. Participants described varied responses to stress, including different appraisals of challenging situations and coping strategies such as peer support, self-care, and use of institutional resources. Conclusion: Stress in nursing education reflects a dynamic interaction between individual appraisal, coping resources, and educational and interpersonal contexts. Although findings are limited to one institution, they highlight the importance of accessible, flexible, and culturally responsive support and of addressing modifiable educational stressors alongside strengthening students' coping resources.

Abstract Aim: Examine cross-sectional associations between mid-pregnancy food intake indicators and prenatal depressive symptomatology. Methods: This secondary analysis of the Comparison of Two Screening Strategies for Gestational Diabetes trial (N = 718) examined domains of mid-pregnancy food intake (direct timing, energy timing, meal/snack structure, meal energy distribution, diet quality) derived from 24-hour dietary recalls. Depressive symptoms were measured with the Edinburgh Postnatal Depression Scale (EPDS). Generalized linear models examined associations between food intake indicators, total, and high (EPDS [&ge;]13) depressive symptoms. Results: Mean (SD) EPDS score was [6.3 (4.9)]; 12.4% (n = 89) had high depressive symptoms. Eating frequency (B = 0.08 [0.02, 0.14], p = 0.009), snack frequency (B = 0.06 [0.00, 0.12], p = 0.040), nighttime snacking frequency (B = 0.06 [0.00, 0.11], p = 0.041), and total daily energy intake (B = 0.06 [0.01, 0.12], p = 0.031) were positively associated with total depressive symptoms. Energy intake from breakfast (PR = 1.2 [1.0, 1.3], p = 0.017) was associated with a higher prevalence of high depressive symptoms. Energy intake from dinner (PR = 0.81 [0.69, 0.94], p = 0.007), later timing of the first eating episode (PR = 0.83 [0.70, 0.99], p = 0.034) and first energy quartile (PR = 0.84 [0.70, 1.0], p = 0.048), were associated with a lower prevalence of high depressive symptoms. Conclusion: These findings extend prior chrononutrition-depression literature to the prenatal period, implicating eating frequency, energy intake, and meal energy timing and distribution in depressive symptomatology during pregnancy, warranting further longitudinal investigation.

Background: Unpaid caregiving is a recognised social determinant of health, yet most research treats it as a fixed exposure measured at a single time point, and little is known about how patterns of caregiving transitions relate to health behaviours. Methods: Secondary analysis of the UK Household Longitudinal Study (waves 2 to 13, approximately 2010 to 2023; n=25,049). Latent class analysis was applied to binary caregiving status across 12 waves to identify caregiving trajectories. Associations between trajectories and four health behaviours (physical inactivity, fruit and vegetable consumption, problematic drinking, current smoking) at waves 7 to 13 were estimated using logistic and linear regression, adjusting for sociodemographic, health and baseline behavioural confounders. Results: An eight-class solution identified a non-caregiving class comprising 62.9% (n=15,760) of the sample. Among caregivers (n=9,289), trajectories were Temporary (20.0%), Former-short (20.2%), Former-long (10.9%), Emerging-short (15.4%), Emerging-long (11.6%), Long-term (15.7%) and Recurrent (6.3%). In fully adjusted models, Recurrent caregivers had higher odds of smoking (OR=1.67, 95%CI: 1.17 to 2.40) compared with non-caregivers but lower odds of physical inactivity (OR=0.65, 95%CI: 0.53 to 0.81) and problematic drinking (OR=0.75, 95%CI: 0.59 to 0.94). Associations for other trajectory classes were largely attenuated after adjustment. Conclusion: The pattern and timing of caregiving transitions are an under-explored dimension of the caregiving experience. Recurrent caregivers had a distinctive profile, with elevated smoking but lower physical inactivity and problematic drinking. Recurrent caregiving should be recognised alongside intensity and duration, and support systems better equipped for people who move into and out of care repeatedly.

Aims/hypothesis Higher body mass index (BMI) is associated with higher levels of HbA1c and glucose in conventional observational studies from sub-Saharan Africa, but its causal relationship in this population has not been explored. Mendelian randomization (MR) which leverages genetic variants can strengthen causal inference. However, its application in African ancestry populations is limited. The aim of this study was to determine whether causal effects of BMI on glycated haemoglobin (HbA1c) and random glucose differ between African and European populations. Methods We used two-sample MR to estimate the effects of BMI on HbA1c and random glucose in adults of African and European ancestries. We conducted a cross-ancestry BMI genome-wide association study (GWAS) from the Africa-Wits International Network for the Demographic Evaluation of Populations and Their Health (INDEPTH) Partnership for Genomic Studies (AWI-Gen) dataset of African adults (N=10,476) and the largest BMI GWAS in Europeans (N~700,000). From the cross-ancestry GWAS we identified 428 independent genome-wide significant variants and of those, 363 single nucleotide polymorphisms (SNPs) had consistent direction of effect in both Africans and Europeans. These variants were then used as genetic instruments to proxy BMI for both Africans and Europeans. Primary outcome data for African and European populations were obtained from UK Biobank summary statistics for HbA1c (5,790 Africans and 400,825 Europeans) and random glucose (5,750 Africans and 314,916 Europeans), with additional results for HbA1c from the MAGIC multi-ancestry GWAS comprised of Ugandan individuals (N=4,441), African Americans (N= 6,647), and Europeans (N=146,806). Main analyses used the inverse variance weighted (IVW) method, with sensitivity analyses conducted using MR-Egger, weighed median and weighted mode approaches. Results The main IVW analyses in UK Biobank provided support for higher BMI causally increasing HbA1c levels in both Africans (0.26 SD higher HbA1c per 1 SD BMI, 95% CI 0.07, 0.45) and Europeans (0.27 SD higher HbA1c per 1 SD BMI, 95% CI 0.22, 0.32). UK Biobank main analyses also supported higher BMI increasing random glucose in Africans (0.21 SD higher mean glucose per 1 SD BMI, 95%CI 0.03, 0.37) and Europeans (0.15 SD higher mean glucose per 1 SD BMI, 95%CI 0.12, 0.18). Sensitivity analyses suggested these results were not biased by unbalanced horizontal pleiotropy. Results from MAGIC also showed that higher BMI causally increased HbA1c in Europeans (0.04% higher HbA1c per 1 SD BMI, 95% CI 0.02, 0.05), though results for African Americans (0.01% higher HbA1c per 1 SD BMI, 95% CI -0.05, 0.07) and Ugandans (0.02% lower HbA1c per 1 SD BMI, 95% CI -0.10, 0.05) spanned the null. Conclusion/interpretation We have found broadly similar effects of BMI on HbA1c and random blood glucose in African and European populations. However, much larger GWAS of glycaemic traits in African and other non European populations are needed to strengthen causal inference and support equitable translation of these findings. The method that we have used to obtain identical strong genetic instrumental variables (IVs) for both European and African populations may have value for other MR studies interested in exploring differences in effects between different population groups.

Abstract Unplanned Extubation is a frequent adverse event in Neonatal Intensive Care Units (NICUs), that is associated with increased morbidity, prolonged hospitalization and financial costs. Evidence suggests that unplanned extubation (UE) is preventable through the management of its risk factors. Many modifiable UE risk factors are directly related to nursing care, thus empowering nurses through education can improve neonatal safety outcomes. This study aimed to evaluate the effectiveness of a structured educational intervention in improving nurses knowledge and practices related to UE in NICUs. A quasi-experimental pretest-posttest study was conducted in two tertiary hospitals in northern Jordan. One hospital is university-affiliated and one is governmental hospital. Participating Nurses in the selected settings received a four-week multimodal educational intervention related to UE. The intervention comprised of face-face session, WhatsApp-based educational messages, educational videos and placement of a poster in the NICU. Knowledge and practices of 58 nurses were assessed at baseline, post intervention and one month later using a validated questionnaire and direct observation. A baseline rate of UE was also measured in both settings with rate of 5 events per 100 ventilator days in the university-affiliated compared to 32 events per 100 ventilator days in governmental hospital. Repeated-measures and mixed-design ANOVA revealed significant improvements in nurses knowledge in both settings with a large effect size (p{superscript 2} = .60). Also, the observed preventive practices scores also improved significantly and remained elevated at one-month follow-up (p{superscript 2} = .50). Older age was associated with lower baseline knowledge, though this was diminished post study intervention. Whereas no demographic variables were associated with practice scores. The high rates of UE highlight the need for quality improvement. Study findings suggest that UE-focused education is a feasible and cost-effective strategy for strengthening neonate nurses competencies regarding safer care for mechanically ventilated neonates in the NICUs.

Early life adversity is a recognised risk factor for poor health in later life, but its relationship with allostatic load (AL; a measure of cumulative physiological stress) remains underexplored across populations around the world. This study builds evidence to test a life course approach to AL using harmonised data from six longitudinal ageing cohorts: Health and Retirement Study (US, N=2,427), English Longitudinal Study of Ageing (England, N=2,038), The Irish Longitudinal Study on Ageing (Ireland, N=8,184), Survey of Health Ageing and Retirement in Europe (Europe, N=4,079), China Health and Retirement Longitudinal Study (China, N=5,220), and Indonesia Family Life Survey (Indonesia, N=1,243). Childhood information at aged ten to sixteen was collected retrospectively from adults aged 65 on average. An AL score is constructed using biomarker data and a latent construct of early life adversity constructed to address recall bias. Results show that early life poverty is significantly associated with raised AL in Ireland, China, and Indonesia, supporting the impact of early life experiences on older adulthood. However, studies from other countries do not confirm statistical significance. These findings document that experiencing poverty during development phase in some settings is associated with higher AL in later life, however further analyses are required to explore possible variations across different populations and their social and economic context. These results add further evidence that social determinants of health, including child poverty, in some settings, contribute to cumulative physiological stress across the life course, and that policies and actions to reduce child poverty can have beneficial effects not only as children, but also as older adults.