Tween Research Articles

Food emulsifiers increase toxicity of food contaminants in three human GI tract cell lines

Food products simultaneously containing both food contaminants and emulsifiers are common in baked products, coffee and chocolate. Little is known regarding how food contaminants and emulsifiers interact and alter toxicity. Recent studies have shown that while emulsifiers themselves have little toxicity, they could cause changes in the gut microenvironment and lead to issues such as increased uptake of allergens. This study examined toxic effect of two common process contaminants acrylamide (AA) and benzo [a]pyrene (BAP) combined with food emulsifiers polyoxyethylene sorbitan monooleate (TW) or glycerol monostearate (G). In liver cell line HepG2 and gastrointestinal cell lines HIEC6 and Caco-2, toxicities of AA and BAP were increased by TW but not by G as indicated by decrease in IC50 values. Addition of TW also exacerbated gene expression changes caused by AA or BAP. Cellular uptake and cell membrane permeability were enhanced by TW but not by G, but tight junction proteins of Caco-2 monolayer was impacted by both emulsifiers. These results suggested that TW could increase toxicity of AA and BAP through increasing cell permeability thus chemical uptake and potentially through other interactions. The study is to draw the attention of regulators on the potential synergistic interaction of co-occurring chemicals in food.

Disclosing peer sexual harassment in the transition from late childhood to early adolescence

ABSTRACT Although students are encouraged to disclose peer sexual harassment, no studies have investigated disclosure among adolescents. This study investigated the extent of peer sexual harassment disclosure, to whom students make disclosures, and different characteristics associated with disclosure. Three-wave annual data from middle-school students (T1: age 10, N = 448) were analyzed. The findings showed that half of sexually harassed students made disclosures, most often to friends. Disclosure to adults declined across time. Slight gender differences were found, with girls being more likely to make a disclosure. Logistic regressions showed that individual (e.g., self-assertive efficacy) and social characteristics (e.g., social support) increased disclosure, but the results were inconsistent. This study provides a unique contribution by showing that much of the sexual harassment occurring within school remains undisclosed. This points toward the importance of early intervention, since sexual harassment becomes increasingly hidden from adults as students progress through middle school.

Unverricht-Lundborg Disease: Tackling the Challenges of a Complex Clinical Picture


 Unverricht-Lundborg disease (ULD), also called progressive myoclonic epilepsy type 1, is characterized by stimulus-induced myoclonus and seizures without major progressive cognitive deficit, usually presenting during late childhood and early adolescence. It is an autosomal recessive disease, and, so far, only pathogenic variants in the gene encoding cystatin B (CSTB) have been described. We report the case of a 9-year-old boy who presented with generalized tonic-clonic seizures and developed paroxysmal myoclonic events over several years. The patient was started on antiseizure medication, but disease progression resulted in several changes to the therapeutic scheme, with highly variable clinical responses. The genetic study detected the pathogenic variant c.67-1G>C p.(?) in heterozygosity in the CSTB gene, after having identified the typical dodecameric expansion in the other allele, confirming the diagnosis of ULD.

Prenatal metal exposures and childhood gut microbial signatures are associated with depression score in late childhood

BackgroundChildhood depression is a major public health issue worldwide. Previous studies have linked both prenatal metal exposures and the gut microbiome to depression in children. However, few, if any, have studied their interacting effect in specific subgroups of children. ObjectivesUsing an interpretable machine-learning method, this study investigates whether children with specific combinations of prenatal metals and childhood microbial signatures (cliques or groups of metals and microbes) were more likely to have higher depression scores at 9–11 years of age. MethodsWe leveraged data from a well-characterized pediatric longitudinal birth cohort in Mexico City and its microbiome substudy (n = 112). Eleven metal exposures were measured in maternal whole blood samples in the second and third trimesters of pregnancy. The gut microbial abundances were measured at 9–11-year-olds using shotgun metagenomic sequencing. Depression symptoms were assessed using the Child Depression Index (CDI) t-scores at 9–11 years of age. We used Microbial and Chemical Exposure Analysis (MiCxA), which combines interpretable machine-learning into a regression framework to identify and estimate joint associations of metal-microbial cliques in specific subgroups. Analyses were adjusted for relevant covariates. ResultsWe identified a subgroup of children (11.6 % of the sample) characterized by a four-component metal-microbial clique that had a significantly high depression score (15.4 % higher than the rest) in late childhood. This metal-microbial clique consisted of high Zinc in the second trimester, low Cobalt in the third trimester, a high abundance of Bacteroides fragilis, a high abundance of Faecalibacterium prausnitzii. All combinations of cliques (two-, three-, and four-components) were significantly associated with increased log-transformed t-scored CDI (β = 0.14, 95%CI = [0.05,0.23], P < 0.01 for the four-component clique). SignificanceThis study offers a new approach to chemical-microbial analysis and a novel demonstration that children with specific gut microbiome cliques and metal exposures during pregnancy may have a higher likelihood of elevated depression scores.

Unveiling mortality risk factors in paediatric sickle cell disease patients during acute crises in the Democratic Republic of the Congo

Sickle cell disease (SCD) is a significant health burden in the Democratic Republic of the Congo (DRC). This study aims to identify predictive factors of mortality in SCD children admitted to emergency care in Lubumbashi, DRC. We performed a non-interventional cohort follow-up on SCD patients aged 0 to 16 admitted for a “true emergency”. Demographic, clinical, and biological data were collected. Univariate and multivariate logistic regression analyses were performed to identify significant risk factors associated with mortality. Among the 121 patients included, 24 died during the follow-up period. Univariate regression revealed age, Mikobi score, referral origin, stroke, and severe infection as significant risk factors. Multivariate analyses identified Hb, WBC, SR, and LDH as predictive factors of mortality. Notably, patients aged 12 to 16 years faced a higher risk, shifting the age of mortality from early to late childhood and adolescence. This study provides valuable insights into mortality risk factors for paediatric SCD patients during acute crises. Early diagnosis, regular follow-up, and therapeutic education are essential to improve patient outcomes and survival rates. These findings contribute to better disease management and targeted interventions, aiming to reduce mortality associated with SCD.

Dietary Emulsifier Exposure in People With Inflammatory Bowel Disease Compared With Healthy Controls: Is There a Cause for Concern?

Emulsifiers are implicated in the pathogenesis of inflammatory bowel disease (IBD). Few studies have examined emulsifier intake in people with existing IBD. We aimed to describe the frequency of exposure to 6 selected emulsifiers in a contemporary cohort of people with IBD and compare intake with healthy controls (HCs). Baseline food records from participants in an Australian prospective cohort study examining the microbiome of IBD patients and HCs were analyzed. Exposure to inflammatory emulsifiers polysorbate-80 (P80); carboxymethylcellulose (CMC); carrageenan; xanthan gum (XG); lecithin (soy and sunflower) and mono- and diglycerides of fatty acids (MDGs) were determined by examining ingredient lists. Frequency of emulsifier exposure between groups (IBD vs HC, Crohn's disease [CD] vs ulcerative colitis [UC], IBD children vs adults, active disease vs remission) was examined after controlling for confounders. Records from 367 participants were analyzed (n = 176 IBD, of which there were 101 CD, 75 UC, and 191 HC patients). In total, 5022 unique food items were examined, with 18% containing 1 or more emulsifier of interest. Inflammatory bowel disease participants had significantly higher total daily emulsifier exposure compared with HCs (2.7 ± 1.8 vs 2.3 ± 1.6, P = .02). In IBD participants, emulsifiers with the highest daily exposure were MDGs (1.2 ± 0.93), lecithin (0.85 ± 0.93), and XG (0.38 ± 0.42). There were no recorded exposures to P80. Inflammatory bowel disease participants were exposed to more emulsifiers than HCs. Intake of inflammatory emulsifiers were low or nonexistent, suggesting their presence in the food supply are not as common as frequently stated.

Development of the triadic neural systems involved in risky decision-making during childhood

Risk-taking often occurs in childhood as a compex outcome influenced by individual, family, and social factors. The ability to govern risky decision-making in a balanced manner is a hallmark of the integrity of cognitive and affective development from childhood to adulthood. The Triadic Neural Systems Model posits that the nuanced coordination of motivational approach, avoidance and prefrontal control systems is crucial to regulate adaptive risk-taking and related behaviors. Although widely studied in adolescence and adulthood, how these systems develop in childhood remains elusive. Here, we show heterogenous age-related differences in the triadic neural systems involved in risky decision-making in 218 school-age children relative to 80 young adults. Children were generally less reward-seeking and less risk-taking than adults, and exhibited gradual increases in risk-taking behaviors from 6 to 12 years-old, which are associated with age-related differences in brain activation patterns underlying reward and risk processing. In comparison to adults, children exhibited weaker activation in control-related prefrontal systems, but stronger activation in reward-related striatal systems. Network analyses revealed that children showed greater reward-related functional connectivity within and between the triadic systems. Our findings support an immature and unbalanced developmental view of the core neurocognitive systems involved in risky decision-making and related behaviors in middle to late childhood.

The impact of age-specific childhood body-mass index on adult cardiometabolic traits: a Mendelian randomization study.

To evaluate the causal relationship between childhood body-mass index (BMI) at different ages and adult cardiometabolic traits. We retrieved genetic instrument variables (IVs) for exposures (standardized BMI at newborn, infant, toddler and late childhood), cardiometabolic traits and potential confounders or mediators (adult BMI, SHBG, testosterone and age at menarche) from the corresponding genome-wide association analysis. We performed univariate and multivariable Mendelian randomization (MR) to dissect associations between age-specific childhood BMI and adult cardiometabolic outcomes. Odds ratio was used to present the direction of the causal association. In univariate MR, higher newborn BMI was causally associated with reduced risk for type 2 diabetes in women. Late childhood BMI was associated with increased risk for female diabetes and coronary artery disease (CAD), myocardial infarction (MI), and chronic kidney disease (CKD) in general population. Among these associations, only association between late childhood BMI with MI remained significant after adjusting for adult male BMI and sex hormones, (OR = 1.120, 95% CI 1.023-1.226, p = 0.014). Besides, in multivariable MR, we found evidence for causal association between newborn BMI with reduced risk for CAD (OR = 0.862, 95% CI 0.751-0.989, p = 0.034) and MI (OR = 0.864, 95% CI 0.752-0.991, p = 0.037) in men. No obvious impact of infant or toddler BMI was identified on the above-mentioned diseases. For continuous cardiometabolic traits, in all age epochs except infant, higher BMI was associated with increased level of fasting glucose in women. BMI at birth and late childhood exerts different impact on adult cardiometabolic diseases, while BMI at infant and toddler ages is not causally associated with these outcomes. The effect of childhood BMI may be influenced by sex disparities.

Animal and plant protein intake during infancy and childhood DNA methylation: a meta-analysis in the NutriPROGRAM consortium

ABSTRACT Background Higher early-life animal protein intake is associated with a higher childhood obesity risk compared to plant protein intake. Differential DNA methylation may represent an underlying mechanism. Methods We analysed associations of infant animal and plant protein intakes with DNA methylation in early (2−6 years, N = 579) and late (7̄−12 years, N = 604) childhood in two studies. Study-specific robust linear regression models adjusted for relevant confounders were run, and then meta-analysed using a fixed-effects model. We also performed sex-stratified meta-analyses. Follow-up analyses included pathway analysis and eQTM look-up. Results Infant animal protein intake was not associated with DNA methylation in early childhood, but was associated with late-childhood DNA methylation at cg21300373 (P = 4.27 × 10¯8, MARCHF1) and cg10633363 (P = 1.09 × 10¯7, HOXB9) after FDR correction. Infant plant protein intake was associated with early-childhood DNA methylation at cg25973293 (P = 2.26 × 10−7, C1orf159) and cg15407373 (P = 2.13 × 10−7, MBP) after FDR correction. There was no overlap between the findings from the animal and plant protein analyses. We did not find enriched functional pathways at either time point using CpGs associated with animal and plant protein. These CpGs were not previously associated with childhood gene expression. Sex-stratified meta-analyses showed sex-specific DNA methylation associations for both animal and plant protein intake. Conclusion Infant animal protein intake was associated with DNA methylation at two CpGs in late childhood. Infant plant protein intake was associated with DNA methylation in early childhood at two CpGs. A potential mediating role of DNA methylation at these CpGs between infant protein intake and health outcomes requires further investigation.

A teacher's role in developing early social intelligence at daycare

This research is aimed at learning the role of teachers in promoting social intelligence for younger age children. This type of research is a descriptive qualitative. The research is done in kindergarten in the great wrwanman village, the jombang district, jember. Based on the research that has been done that the development of emotional social aspects in preteen age should be considered. The importance of developing emotional social relationships for a child at a young age helps him to understand the environment, the importance of emotional social aspects for a child because he or she is able to socialize. At an early age, children can be taught to build social relationships. Through introduction, children begin to interact and share. Teachers are one of the critical components of the education and teaching learning process. There are three roles of teachers in the process of developing emotional social parenting at rahman's kindergarten. Among other things: a teacher's role as a model in a teacher's learning activity provides a good example for children to appreciate each other, to speak politely (saying please, thank you and sorry). The teacher's role as inspiration in teacher learning is discovering new ideas related to the learning process, inspiring teaching is developing a more creative mind pattern of the child and leaving the child dependent not in class, but becoming a lifelong learning. The teacher's role as a motivator, in developing a child's emotional social through activity

Dietary emulsifier consumption accelerates type 1 diabetes development in NOD mice

The rapidly increasing prevalence of type 1 diabetes (T1D) underscores the role of environmental (i.e. non-genetic) determinants of T1D development. Such factors include industrialized diets as well as the intestinal microbiota with which they interact. One component of industrialized diets that deleteriously impact gut microbiota is dietary emulsifiers, which perturb intestinal microbiota to encroach upon their host promoting chronic low-grade intestinal inflammation and metabolic syndrome. Hence, we investigated whether 2 dietary emulsifiers, carboxymethylcellulose (CMC) and polysorbate-80 (P80), might influence the development of T1D in NOD mice, which spontaneously develop this disorder. We observed that chronic emulsifier exposure accelerated T1D development in NOD mice, which was associated with increased insulin autoantibody levels. Such accelerated T1D development was accompanied by compositional and functional alterations of the intestinal microbiota as well as low-grade intestinal inflammation. Moreover, machine learning found that the severity of emulsifier-induced microbiota disruption had partial power to predict subsequent disease development, suggesting that complex interactions occur between the host, dietary factors, and the intestinal microbiota. Thus, perturbation of host–microbiota homeostasis by dietary emulsifiers may have contributed to the post-mid-20th-century increase in T1D.

Joint developmental trajectories of internalizing and externalizing problems from mid-childhood to late adolescence and childhood risk factors: Findings from a prospective pre-birth cohort.

There is limited evidence on heterogenous co-developmental trajectories of internalizing (INT) and externalizing (EXT) problems from childhood to adolescence and predictors of these joint trajectories. We utilized longitudinal data from Raine Study participants (n = 2393) to identify these joint trajectories from 5 to 17 years using parallel-process latent class growth analysis and analyze childhood individual and family risk factors predicting these joint trajectories using multinomial logistic regression. Five trajectory classes were identified: Low-problems (Low-INT/Low-EXT, 29%), Moderate Externalizing (Moderate-EXT/Low-INT, 26.5%), Primary Internalizing (Moderate High-INT/Low-EXT, 17.5%), Co-occurring (High-INT/High-EXT, 17%), High Co-occurring (Very High-EXT/High-INT, 10%). Children classified in Co-occurring and High Co-occurring trajectories (27% of the sample) exhibited clinically meaningful co-occurring problem behaviors and experienced more adverse childhood risk-factors than other three trajectories. Compared with Low-problems: parental marital problems, low family income, and absent father predicted Co-occurring and High Co-occurring trajectories; maternal mental health problems commonly predicted Primary Internalizing, Co-occurring, and High Co-occurring trajectories; male sex and parental tobacco-smoking uniquely predicted High Co-occurring membership; other substance smoking uniquely predicted Co-occurring membership; speech difficulty uniquely predicted Primary Internalizing membership; child's temper-tantrums predicted all four trajectories, with increased odds ratios for High Co-occurring (OR = 8.95) and Co-occurring (OR = 6.07). Finding two co-occurring trajectories emphasizes the importance of early childhood interventions addressing comorbidity.

Effect of the peripartum depressive symptoms on the Internet use disorder of their offspring in late childhood: retrospective longitudinal study

Internet use disorder (IUD) is an emerging social and mental health concern. This study aimed to analyze the relative risk of IUD in late childhood among children whose mothers experienced peripartum depressive symptoms. This study included 762 participants (397 boys and 365 girls) and was conducted in 2017 (aged 9) and 2019 (aged 11). We analyzed the adjusted relative risk of being at high risk for IUD based on whether the mother experienced depressive symptoms during pregnancy or one month after delivery. We also considered the persistence of depressed mood for 4 months after delivery and the severity of peripartum depressive symptoms. From 2017, 20.7% of boys and 14.0% of girls were at high risk of developing IUD. Compared to the non-peripartum depressive group, girls whose mothers experienced peripartum depressive symptoms and those that persisted for 4 months were 1.084 and 1.124 times more likely to be at high risk of IUD (95% confidence interval = 1.005–1.170 and 1.013–1.248), respectively. There were no statistically significant differences among boys. Peripartum depressed mood could be one of risk factors of IUD. IUD needs to be monitored in children whose mothers experienced peripartum depressive symptoms.

The Influence of Acute Hypoxia on Oxygen Uptake and Muscle Oxygenation Kinetics During Cycling Exercise in Prepubertal Boys.

To examine the effect of normobaric hypoxia on pulmonary oxygen uptake (V˙O2) and muscle oxygenation kinetics during incremental and moderate-intensity exercise in children. Eight prepubertal boys (9-11y)performed incremental cycle tests to exhaustion in both normoxia and hypoxia (fraction of inspired O2 of 15%) followed by repeat 6-minute transitions of moderate-intensity exercise in each condition over subsequent visits. Maximal oxygen uptake (V˙O2max) was reduced in hypoxia compared with normoxia (1.69 [0.20] vs 1.87 [0.26]L·min-1, P = .028), although the gas exchange threshold was not altered in absolute terms (P = .33) or relative to V˙O2max (P = .78). During moderate-intensity exercise, the phase II V˙O2 time constant (τ) was increased in hypoxia (18 [9] vs 24 [8]s, P = .025), with deoxyhemoglobin τ unchanged (17 [8] vs 16 [6], P ≥ .28). In prepubertal boys, hypoxia reduced V˙O2max and slowed V˙O2 phase II kinetics during moderate-intensity exercise, despite unchanged deoxyhemoglobin kinetics. These data suggest an oxygen delivery dependence of V˙O2max and moderate-intensity V˙O2 kinetics under conditions of reduced oxygen availability in prepubertal boys.

Do temperament trajectories from late childhood through adolescence predict success in school? Findings from a longitudinal study of Mexican-origin youth.

School achievement has long-term consequences for occupational success, mental health, and overall psychological adjustment. The present study examined the association between temperament trajectories from late childhood through adolescence and academic outcomes during late adolescence and young adulthood. Data come from the California Families Project, a longitudinal study of 674 Mexican-origin youth assessed 12 times from Age 10 to 23, and from school records. Results from latent growth curve models indicate that higher levels of Effortful Control (EC) at Age 10 were associated with better academic achievement (i.e., higher high school grade point average and test scores, greater likelihood of high school graduation and college attendance) in late adolescence and young adulthood. Higher levels of Negative Emotionality (NEM) at Age 10 were associated with worse academic achievement, but this effect did not hold for all facets of NEM. Neither the levels nor slopes of Positive Emotionality (Surgency, Affiliation) consistently predicted school achievement. There were no main effects of the EC or NEM slopes; however, statistically significant interactions between these slopes and parental monitoring emerged. When parental monitoring was low, youth who experienced greater increases in EC (vs. flat or decreasing slopes) had better academic achievement, and youth who experienced greater increases in NEM had worse academic achievement; in contrast, when parents closely monitored their children, changes in EC and NEM were only weakly associated with achievement. Overall, these findings demonstrate that temperament in late childhood, and changes in temperament across adolescence, have important prospective effects on academic achievement. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Polysorbate 80-containing ionizable lipid nanoparticles for mRNA delivery.

Ionizable lipid nanoparticles have demonstrated remarkable success as mRNA vaccine carriers and represent one of the most promising gene drug delivery vehicles. However, polyethylene glycol (PEG), one of the major components, can cause immunogenic reactions, anaphylaxis and increased blood clearance, leading to toxic side effects and reduced efficacy. In this study, we utilize polysorbate 80 (PS80) as a PEG alternative in formulating eGFP mRNA-loaded ionizable lipid nanoparticles (PS80-iLNPs), aiming to enhance stealth properties, uptake efficiency, and biosafety. Our findings revealed that PS80-iLNPs enhanced the stealthiness and resistance to serum interference. Compared to PEG-containing ionizable lipid nanoparticles (PEG-iLNPs), PS80-iLNPs showed a 1.14-fold increase in stealthiness. Moreover, at a total lipid concentration of 50 μg mL-1, PS80-iLNPs exhibited 1.12 times higher cell viability compared to PEG-iLNPs. Notably, under serum interference, PEG-iLNPs showed a 44.97% uptake reduction, whereas PS80-iLNPs exhibited a modest 30.55% decrease, underscoring its superior serum resistance. This work demonstrated that PS80 could serve as a suitable substitute for PEG, thus signifying an excellent basis for the development of PEG-free ionizable lipid nanoparticles.

Extraction of Alpha-cypermethrin Pesticides from Aqueous Solution by Emulsion Liquid Membrane

This research examines the emulsion liquid membrane (ELM) extraction efficiency and stability to abstraction of alpha-cypermethrin pesticides from aqueous solution when blended surfactants are used in the liquid membrane composition. The stability of the membrane was examined in the aspect of the emulsion breakdown time and distribution of droplet size. The ingredients employed in ELM were Span80 (sorbitan monooleate) and Tween80 (polyoxyethylene sorbitan monooleate) as surfactants and a mixture of kerosene, sunflower oil (3:7) as diluents and stripping agent was used sodium hydroxide (NaOH). Some parameters were assessed, including the value of Hydrophilic Lipophilic Balance (HLB), blended surfactant concentration, homogenizer speed, emulsification time, and NaOH concentration as a stripping agent. According to the results, a stable emulsion was created at HLB (5.37), blended surfactant 3 % (w/v), 12,700 rpm of homogenizer speed, 9 min of emulsification time, and 0.05 N of NaOH. Under these circumstances, 89.2 % of the alpha-cypermethrin was extracted with 1.8 % emulsion breakage. As a result, the combinations of (Span80 with Tween80) have enormous potential as surfactants and they can improve the stability of the emulsion. Additionally, completed was mass transfer investigation and extraction kinetics

The Cardiorespiratory Fitness of Children and the Anthropometric Determinants During Late Childhood Within South East Wales: Potential Implications for Future Health.

Objective. This study investigated cardiorespiratory fitness (CRF) levels and the relationship with field-based measures of anthropometry in children aged 10 to 11 years. Methods. A total of 288 boys and 257 girls participated in the study. CRF (20 m shuttle run) and several field-based measures of anthropometry were assessed. Multiple regression was utilized for all data analysis. Results. Boys performed significantly better than girls on the CRF test (P < .001) and achieved higher classifications of CRF based on centile norms compared to girls. All measures of anthropometry were significant predictors of CRF, (P < .001), and each measure was significant in predicting a negative trajectory of CRF performance when they increased in value (P < .05). Conclusion. The study findings add to the international reporting of CRF and the use of simple field-based measures of anthropometry alongside the use of BMI to predict CRF for health with Welsh school children (UK).

Supplemental Material for Using Machine Learning to Derive Neurobiological Subtypes of General Psychopathology in Late Childhood

Supplemental Material for Using Machine Learning to Derive Neurobiological Subtypes of General Psychopathology in Late Childhood

The dual journey: The development of twins' relationships throughout childhood.

Twin bonds, likely the most enduring of human relationships, provide both solace and rivalry for twins. Using an evolutionary psychology perspective, this chapter scrutinizes twins' bonds from prenatal stages to childhood to better understand their unique relationships. Twins' interactions, which begin in the womb, establish patterns of cooperation and competition. The initial years pose parenting challenges that shape the twins' experiences of dependency and rivalry. As twins grow, five dimensions-closeness, dependence, conflict, rivalry, and dominance-emerge, evolving distinctly between monozygotic twins (MZ: sharing close to 100% of their genes) and dizygotic twins (DZ: sharing on average 50% of their genetic variance). The chapter notes the closer relationship MZ twins share compared to DZ twins. While the closeness and dependence among DZ twins decline throughout childhood, these elements remain stable in MZ twins. The effect of zygosity on conflict and rivalry is less clear. For both MZ and DZ twins, conflict stays steady, while rivalry intensifies with school entry, probably driven by external comparisons, but lessens as twins develop into late childhood. Unlike singletons, where birth order dictates dominance dynamics, in twins, this dynamic is more variable and becomes more defined by around 6.5 years of age. Several factors are presented as impacting the nature of the twins' relationships: the evolvement of 'twin language', the parenting style and the differential parenting they receive. This exploration into the development of twins' relationships underlines the importance of tailored caregiving and invites further research into the genetic and environmental factors that shape close bonds.