Breastfeeding Duration Is Not Associated With Offspring Inflammatory Bowel Disease Risk in Three Population-Based Birth Cohorts.

BACKGROUND & AIMS: Breastfeeding is critical for offspring health and development. Although many observational studies report a protective effect between breastfeeding and inflammatory bowel disease (IBD), the relationship is not well-understood. METHODS: We used prospectively collected data from 3 population-based birth cohorts (Danish National Birth Cohort, Norwegian Mother, Father, and Child Cohort, and All Babies in Southeast Sweden) and cross-linked national registers to ascertain the impact of breastfeeding duration on offspring IBD risk in each country, using adjusted Cox proportional regression analyses. We performed meta-analyses to determine pooled estimates. RESULTS: We included 148,737 offspring and 169,510 offspring in analyses of exclusive and any breastfeeding duration, respectively. During median follow-up of 16.3-22.3 years, between 1996 and 2021, 543 offspring were diagnosed with IBD. In each country, there was no association between exclusive breastfeeding duration and offspring IBD risk after adjusting for birth year (Denmark), offspring sex, parental IBD status, maternal education, smoking during pregnancy, age at delivery, mode of delivery, preterm birth, and small for gestational age. The pooled adjusted hazard ratio for IBD was 1.24 (95% confidence interval, 0.94-1.62; Q = 0.16, I2 = 0.0%) and 1.02 (95% confidence interval, 0.85-1.21; Q = 1.45, I 2= 0.0%) among offspring breastfed exclusively for ≥6 months and <4 months, respectively, compared with 4-5 months. Similarly, we found null associations in pooled analyses of any breastfeeding duration and IBD, subtypes Crohn's disease and ulcerative colitis, as well as in cohort-specific analyses. CONCLUSIONS: In prospectively collected data from 3 population-based birth cohorts, the duration of exclusive or any breastfeeding was not associated with offspring IBD risk.

Higher incidence of paediatric inflammatory bowel disease by increasing latitude in Norway, but stable incidence by age.

AIM: To examine possible geographical and temporal differences in the incidence of childhood-onset inflammatory bowel disease (IBD) in Norway, motivated by previous research indicating relevant environmental factors explaining changing epidemiology. METHODS: We analysed data from children born in Norway from 2004 to 2012 (n = 541 036) in a registry-based nationwide study. After validating registry diagnoses against medical records, we defined IBD as ≥2 entries of International Classification of Diseases, 10th revision (ICD-10) codes K50, K51 and K52.3 in the Norwegian Patient registry. We estimated hazard ratios (HR) for IBD across four geographical regions with a south-to-north gradient and the incidence by period of birth. RESULTS: By the end of follow-up on 31 December 2020, 799 IBD diagnoses were identified (Crohn's disease: n = 465; ulcerative colitis, n = 293, IBD: unclassified, n = 41). Compared to children in the southernmost region, there was almost a two-fold HR for IBD in children in the most Northern region (HR = 1.94, 95% Cl = 1.47-2.57; Mid region: HR = 1.68, 95% CI = 1.29-2.19, ptrend <0.001). These estimates remained largely unchanged after adjustment for potential confounding factors. The cohorts born in 2004-2006 and 2010-2012 had comparable cumulative incidences, with a slightly higher incidence for those born in 2007-2009. CONCLUSION: We observed an increase in the risk of IBD by increasing latitude which may suggest that environmental factors influence the development of IBD, although non-causal explanations cannot be ruled out.

Atopic Dermatitis in Early Childhood and Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study.

OBJECTIVE: To examine the association between early-life atopic manifestations and later risk of inflammatory bowel disease (IBD), for which prospective data are scarce. STUDY DESIGN: The population-based All Babies in Southeast Sweden (ABIS) and Norwegian Mother, Father, and Child (MoBa) cohorts follow children from birth (ABIS 1997-1999; MoBa 2000-2009) to the end of 2021. Based on validated questionnaires, parents prospectively reported information on asthma, food-related allergic symptoms, atopic dermatitis, and allergic rhinitis by age 3. IBD was defined by ≥ 2 diagnostic records in the national health registries. Cox regression estimated hazard ratios adjusted (aHRs) for parental IBD, atopy, education level, smoking habits, and national origin. Cohort-specific estimates were pooled using a random-effects model. RESULTS: We compiled data on 83 311 children (ABIS, n = 9041; MoBa, n = 74 270). In over 1 174 756 person-years of follow-up, 301 participants were diagnosed with IBD. Children with atopic dermatitis at age 3 had an increased risk of IBD (pooled aHR = 1.46 [95% CI = 1.13-1.88]), Crohn's disease (pooled aHR = 1.53 [95%CI = 1.04-2.26]), and ulcerative colitis (pooled aHR = 1.78 [95%CI = 1.15-2.75]). Conversely, any atopic manifestation by age 3 was not associated with IBD (pooled aHR = 1.20 [95%CI = 0.95-1.52]), nor were analyses specifically focused on early-life food-related allergic symptoms, asthma, and allergic rhinitis. CONCLUSION: While atopic manifestations in early childhood were overall not associated with IBD, children with atopic dermatitis specifically were at increased risk of developing IBD, suggesting shared etiologic traits; these findings might be useful in identifying at-risk individuals for IBD.

No association between long-chain n-3 fatty acid intake during pregnancy and risk of type 1 diabetes in offspring in two large Scandinavian pregnancy cohorts.

AIMS/HYPOTHESIS: The aim of this study was to investigate whether higher dietary intake of marine n-3 fatty acids during pregnancy is associated with a lower risk of type 1 diabetes in children. METHODS: The Danish National Birth Cohort (DNBC) and the Norwegian Mother, Father and Child Cohort Study (MoBa) together include 153,843 mother-child pairs with prospectively collected data on eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake during pregnancy from validated food frequency questionnaires. Type 1 diabetes diagnosis in children (n=634) was ascertained from national diabetes registries. RESULTS: There was no association between the sum of EPA and DHA intake during pregnancy and risk of type 1 diabetes in offspring (pooled HR per g/day of intake: 1.00, 95% CI 0.88, 1.14), with consistent results for both the MoBa and the DNBC. Robustness analyses gave very similar results. CONCLUSIONS/INTERPRETATION: Initiation of a trial of EPA and DHA during pregnancy to prevent type 1 diabetes in offspring should not be prioritised.

Over-investigation and overtreatment in pediatrics: a survey from the European Academy of Paediatrics and Japan Pediatric Society.

Introduction: Avoiding over-investigation and overtreatment in health care is a challenge for clinicians across the world, prompting the international Choosing Wisely campaign. Lists of recommendations regarding medical overactivity are helpful tools to guide clinicians and quality improvement initiatives. We aimed to identify the most frequent and important clinical challenges related to pediatric medical overactivity in Europe and Japan. Based on the results, we aim to establish a (European) list of Choosing Wisely recommendations. Methods: In an online survey, clinicians responsible for child health care in Europe and Japan were invited to rate 18 predefined examples of medical overactivity. This list was compiled by a specific strategic advisory group belonging to the European Academy of Paediatrics (EAP). Participants were asked to rate on a Likert scale (5 as the most frequent/important) according to how frequent these examples were in their working environment, and how important they were considered for change in practice. Results: Of 2,716 physicians who completed the survey, 93% (n = 2,524) came from 17 countries, Japan (n = 549) being the largest contributor. Pediatricians or pediatric residents comprised 89%, and 51% had 10-30 years of clinical experience. Cough and cold medicines, and inhaled drugs in bronchiolitis were ranked as the most frequent (3.18 and 3.07 on the Likert scale, respectively), followed by intravenous antibiotics for a predefined duration (3.01), antibiotics in uncomplicated acute otitis media (2.96) and in well-appearing newborns. Regarding importance, the above-mentioned five topics in addition to two other examples of antibiotic overtreatment were among the top 10. Also, IgE tests for food allergies without relevant medical history and acid blockers for infant GER were ranked high. Conclusion: Overtreatment with antibiotics together with cough/cold medicines and inhaled drugs in bronchiolitis were rated as the most frequent and important examples of overtreatment across countries in Europe and Japan.

No association between disease severity and respiratory syncytial virus subtypes RSV-A and RSV-B in hospitalized young children in Norway.

OBJECTIVE: There is conflicting evidence whether subtypes of Respiratory syncytial virus have different seasonality or are differentially associated with clinical severity. We aimed to explore the associations between disease severity and RSV subtypes RSV-A and RSV-B and to describe the circulation of RSV subtypes pattern by season and age. METHODS: Active prospective hospital surveillance for RSV-A and RSV-B in children <59 months of age was conducted during 2015-2018. All febrile children 12-59 months of age were enrolled, whereas children <12 months were eligible if presenting with fever or respiratory symptoms. Risk factors and upper and lower respiratory tract infection was identified by linkage to national registry data and analyzed using penalized maximum likelihood logistic regression. RESULTS: Both RSV-A and B were found to co-circulate throughout all three study seasons, and no clear seasonal pattern was identified. Likewise, we found no association between sex or measures of severity with RSV-A or RSV-B. There was significantly more RSV-A than RSV-B among children with comorbidities. CONCLUSIONS: No association was found between disease severity or sex and RSV subtypes RSV-A and RSV-B in hospitalized young children in Norway.

Tobacco Smoke Exposure in Early Childhood and Later Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study.

OBJECTIVES: To examine the association between early-life smoking exposure and later risk of inflammatory bowel disease [IBD]. METHODS: We followed 115663 participants from the Norwegian Mother, Father and Child [MoBa] and All Babies in Southeast Sweden [ABIS] cohorts from birth [1997-2009] through 2021. IBD was identified through national patient registers. Validated questionnaire data defined maternal smoking during pregnancy, maternal environmental tobacco smoke [ETS] exposure during pregnancy, and child ETS exposure by ages 12 and 36 months. Cox regression was used to estimate adjusted hazard ratios [aHRs] for sex, maternal age, education level, parental IBD, and origin. Cohort-specific estimates were pooled using a random-effects model. RESULTS: During 1 987 430 person-years of follow-up, 444 participants developed IBD [ABIS, 112; MoBa, 332]. Any vs no maternal smoking during pregnancy yielded a pooled aHR of 1.30 [95% CI = 0.97-1.74] for offspring IBD. Higher level of maternal smoking during pregnancy (compared with no smoking, average ≥6 cigarettes/day: pooled aHR = 1.60 [95% CI = 1.08-2.38]) was associated with offspring IBD, whereas a lower smoking level was not (average 1-5 cigarettes/day: pooled aHR = 1.09 [95% CI = 0.73-1.64]). Child ETS exposure in the first year of life was associated with later IBD (any vs no ETS, pooled aHR = 1.32 [95% CI = 1.03-1.69]). Estimates observed for child ETS exposure by 36 months were similar but not statistically significant. CONCLUSIONS: In this prospective Scandinavian cohort study, children exposed to higher levels of maternal smoking during pregnancy or ETS during the first year of life were at increased risk of later IBD.

Genotypes predisposing for celiac disease and autoimmune diabetes and risk of infections in early childhood.

OBJECTIVES: Infections in early childhood have been associated with risk of celiac disease (CD) and type 1 diabetes (T1D). We investigated whether this is driven by susceptibility genes for autoimmune disease by comparing infection frequency by genetic susceptibility variants for CD or T1D. METHODS: We genotyped 373 controls and 384 children who developed CD or T1D in the population-based Norwegian Mother, Father and Child Cohort study (MoBa) study for human leukocyte antigen (HLA)-DQ, FUT2, SH2B3, and PTPN22, and calculated a weighted non-HLA genetic risk score (GRS) for CD and T1D based on over 40 SNPs. Parents reported infections in questionnaires when children were 6 and 18 months old. We used negative binomial regression to estimate incidence rate ratio (IRR) for infections by genotype. RESULTS: HLA genotypes for CD and T1D or non-HLA GRS for T1D were not associated with infections. The non-HLA GRS for CD was associated with a nonsignificantly lower frequency of infections (aIRR: 0.95, 95% CI: 0.87-1.03 per weighted allele score), and significantly so when restricting to healthy controls (aIRR: 0.89, 0.81-0.99). Participants homozygous for rs601338(A;A) at FUT2, often referred to as nonsecretors, had a nonsignificantly lower risk of infections (aIRR: 0.91, 95% CI: 0.83-1.01). SH2B3 and PTPN22 genotypes were not associated with infections. The association between infections and risk of CD (OR: 1.15 per five infections) was strengthened after adjustment for HLA genotype and non-HLA GRS (OR: 1.24). CONCLUSIONS: HLA variants and non-HLA GRS conferring susceptibility for CD were not associated with increased risk of infections in early childhood and is unlikely to drive the observed association between infections and risk of CD or T1D in many studies.

Celiac Disease Affects 1% of Global Population-Who Will Manage All These Patients? What Are Criteria to Prioritize Along Risk for Complications?

Celiac disease is a common gastrointestinal condition with an estimated global prevalence of up to 1%. Adequate long-term surveillance of patients is imperative to ensure strict adherence to treatment with a gluten-free diet and the ensuing clinical and histologic recovery. Traditionally, this has been accomplished by means of regular on-site attendance at specialist health care facilities, accompanied for most patients by follow-up endoscopic and laboratory tests. However, the rapidly increasing prevalence of celiac disease and the limited health care resources challenge the current centralized and nonindividualized follow-up strategies. The improved noninvasive surveillance tools and online health care services are further changing the landscape of celiac disease management. There is a clear need for more personalized and on-demand follow-up based on early treatment response and patient-related factors associated with long-term prognosis. Additional scientific evidence on the optimal implementation of follow-up for pediatric and adulthood celiac disease is nevertheless called for.

Early-life diet and risk of inflammatory bowel disease: a pooled study in two Scandinavian birth cohorts.

OBJECTIVE: We assessed whether early-life diet quality and food intake frequencies were associated with subsequent IBD. DESIGN: Prospectively recorded 1-year and 3-year questionnaires in children from the All Babies in Southeast Sweden and The Norwegian Mother, Father and Child Cohort Study were used to assess diet quality using a Healthy Eating Index and intake frequency of food groups. IBD was defined as >2 diagnoses in national patient registers. Cox regression yielded HRs adjusted (aHRs) for child's sex, parental IBD, origin, education level and maternal comorbidities. Cohort-specific results were pooled using a random-effects model. RESULTS: During 1 304 433 person-years of follow-up, we followed 81 280 participants from birth through childhood and adolescence, whereof 307 were diagnosed with IBD. Compared with low diet quality, medium and high diet quality at 1 year of age were associated with a reduced risk of IBD (pooled aHR 0.75 (95% CI=0.58 to 0.98) and 0.75 (95% CI=0.56 to 1.00)). The pooled aHR per increase of category was 0.86 (0.74 to 0.99). Pooled aHR for children 1 year old with high versus low fish intake was 0.70 (95% CI=0.49 to 1.00) for IBD, and showed association with reduced risk of UC (pooled aHR=0.46; 95% CI=0.21, 0.99). Higher vegetable intake at 1 year was associated with a risk reduction in IBD. Intake of sugar-sweetened beverages was associated with an increased risk of IBD. Diet quality at 3 years was not associated with IBD. CONCLUSION: In this Scandinavian birth cohort, high diet quality and fish intake in early life were associated with a reduced risk of IBD.

Systematic review of socioeconomic factors and COVID-19 in children and adolescents.

AIM: To systematically review the evidence on Covid-19 infection risk, severity and vaccination uptake among children and adolescents by socioeconomic status. METHODS: We conducted a systematic literature review, using the PubMed database. We searched for articles published from January 2020 to January 2022 using "MeSH" words and titles. The key terms were "COVID", "social status", "socioeconomic factor" and "children". We also searched secondary sources such as published reports and other databases. RESULTS: The search identified 15 relevant articles and reports. This review shows that children of lower socioeconomic status have a higher risk of COVID-19 infection and a higher risk of being hospitalised. Mortality in a global setting was also higher in children with low socioeconomic status, though not observed in high-resourced countries. These children are also less likely to be vaccinated against the SARS-CoV-2 virus. CONCLUSIONS: The higher risk of COVID-19 infection and hospitalisation and lower vaccination coverage in children and adolescents from lower socioeconomic backgrounds demonstrate health disparities also in young age. These disparities should inform health authorities in planning for future pandemics.

Frequency and risk of SARS-CoV-2 reinfections in Norway: a nation-wide study, February 2020 to January 2022.

BACKGROUND: SARS-CoV-2 reinfection rates have been shown to vary depending on the circulating variant, vaccination status and background immunity, as well as the time interval used to identify reinfections. This study describes the frequency of SARS-CoV-2 reinfections in Norway using different time intervals and assesses potential factors that could impact the risk of reinfections during the different variant waves. METHODS: We used linked individual-level data from national registries to conduct a retrospective cohort study including all cases with a positive test for SARS-CoV-2 from February 2020 to January 2022. Time intervals of 30, 60, 90 or 180 days between positive tests were used to define potential reinfections. A multivariable Cox regression model was used to assess the risk of reinfection in terms of variants adjusting for vaccination status, demographic factors, and underlying comorbidities. RESULTS: The reinfection rate varied between 0.2%, 0.6% and 5.9% during the Alpha, Delta and early Omicron waves, respectively. In the multivariable model, younger age groups were associated with a higher risk of reinfection compared to older age groups, whereas vaccination was associated with protection against reinfection. Moreover, the risk of reinfection followed a pattern similar to risk of first infection. Individuals infected early in the pandemic had higher risk of reinfection than individuals infected in more recent waves. CONCLUSIONS: Reinfections increased markedly during the Omicron wave. Younger individuals, and primary infections during earlier waves were associated with an increased reinfection risk compared to primary infections during more recent waves, whereas vaccination was a protective factor. Our results highlight the importance of age and post infection waning immunity and are relevant when evaluating vaccination polices.

Antibiotic use for airway infections in Norwegian children-A national register-based study.

AIM: Respiratory tract infections (RTIs) are major contributors to childhood antibiotic use. We aimed to investigate geographical and temporal trends in the prescription of antibiotics and consultations for RTIs in children <18 years living in Norway from 2010 to 2017. METHODS: In a nationwide observational study, we analysed antibiotic prescriptions from the Norwegian Prescription Database and reimbursed contacts from primary care physicians. We limited the study to airway antibiotics and diagnostic codes indicating RTIs. RESULTS: Antibiotic prescriptions due to an RTI varied from 75 to 134 per 1000 consultation due to RTI across counties in Norway (relative risk 1.79, 95% CI 1.68-1.90 for highest compared to lowest). The use of health care varied from 414 to 585 consultations for RTI per 1000 inhabitant/year (relative risk 1.43, 95% CI 1.41-1.44 for highest compared to lowest). From 2010 to 2017, we observed a 21% reduction in antibiotic prescriptions per RTI consultation and of 6% for the number of consultations for an RTI. At the county level, the use of health care was positively associated with the proportion of RTIs that resulted in antibiotic prescription. CONCLUSION: We found a reduction in doctors' antibiotic prescription and the use of health care for RTIs, and a variation across counties.

Home-Based Double-Blind, Placebo-Controlled Challenges for Diagnosis of Delayed Gluten/Milk Hypersensitivity in Children.

BACKGROUND: Delayed hypersensitivity to gluten and milk protein is frequently reported but may be difficult to diagnose. OBJECTIVE: We aimed to explore if a method of home-based double-blind placebo-controlled food challenges (H-FC) can identify and reduce unnecessary elimination diets in children. METHODS: We included 73 of 92 children aged 1 to 17 years referred to a tertiary allergy clinic from 2011 to 2021 due to self-reported, delayed symptoms to gluten or milk. The children were randomized to H-FC, receiving gluten/milk protein or placebo for 5 to 7 days in a double-blind crossover manner, separated by 3 washout weeks. Patients/parents recorded symptoms using standardized forms. Two crossover periods were used from 2011 to 2016 and 3 periods from 2017 to 2021. A positive challenge required significantly more symptoms during the active period versus the placebo period. After the challenge, reintroduction of milk/gluten was assessed by a follow-up interview. The primary outcome was the proportion of children with a positive challenge. RESULTS: The children, with a mean age of 11 years, had followed a strict gluten-free or milk-protein-free diet for a median duration of 24 months (range: 3-180 months). A positive challenge was observed in 18 of 73 children (25%), more often using 2 (35%) compared with 3 challenge periods (12%). At follow-up, 44 of 55 (80%) children with a negative challenge had successfully reintroduced milk/gluten. CONCLUSIONS: H-FC may be an effective method in avoiding unnecessary elimination diets in children. Only 25% of the challenges were positive, and 80% of the children with negative challenges succeeded in reintroducing the food. Three challenge periods may be necessary to reduce false-positive outcomes.

Early-Life Hygiene-Related Factors and Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study.

BACKGROUND: We aimed to investigate whether early-life hygiene-related factors influenced the risk of inflammatory bowel disease (IBD) in a Scandinavian population and test the association's consistency across cohorts. METHODS: This study followed 117 493 participants in the All Babies in Southeast Sweden study and the Norwegian Mother, Father, and Child Cohort Study. IBD diagnoses were defined by national registers. Comprehensive data on hygiene-related exposures, such as having pets, rural living, daycare attendance, and siblings, were retrieved from questionnaires administered from pregnancy until child's age of 36 months. A multivariable Cox regression model yielded adjusted hazard ratios (aHRs) for IBD accounting for socioeconomic status and perinatal factors. Cohort-specific estimates were pooled using a random-effects model. RESULTS: In over 2 024 299 person-years of follow-up 451 participants developed IBD. In pooled estimates children attending daycare up to 36 months of life vs not attending daycare were less likely to develop Crohn's disease (aHR, 0.60; 95% confidence interval [CI], 0.37- 0.98). Children having 1 or more siblings had a modestly increased risk of IBD (aHR, 1.17; 95% CI, 0.96-1.42; aHR for each sibling, 1.12; 95% CI, 1.01-1.24). The other hygiene factors were not significantly linked to later IBD. In the Norwegian Mother, Father, and Child Cohort Study cohort, bed sharing was associated with an increased risk of IBD, most notably for ulcerative colitis (aHR, 1.67; 95% CI, 1.01-2.78). CONCLUSIONS: In this birth cohort study from 2 high-income Scandinavian countries, some early-life hygiene-related exposures were associated with IBD risk. The generalizability of these results to countries of other socioeconomic level is unknown.

Exposure to some hygiene factors during early childhood seems to be associated with the risk of later inflammatory bowel disease. The direction and magnitude of the associations need to be further studied before any clinical implications.

Effect of arachidonic and docosahexaenoic acid supplementation on quality of growth in preterm infants: A secondary analysis of a randomized controlled trial.

BACKGROUND & AIMS: A balanced supply of arachidonic acid (ARA) and docosahexaenoic acid (DHA) may be crucial for quality of growth in preterm infants. This secondary analysis of a randomized controlled trial aimed to determine the effect of enhanced ARA and DHA supplementation on growth and body composition in infants born before 29 weeks of gestation. Furthermore, we aimed to study associations between human milk feeding, growth patterns and body composition. METHODS: The ImNuT-trial randomized 121 infants to receive a daily supplement with medium chain triglycerides (control) or 100 mg/kg ARA and 50 mg/kg DHA (ARA:DHA group) from the second day of life until 36 weeks postmenstrual age. Growth and body composition were evaluated up to 3 months corrected age. RESULTS: The ARA:DHA group showed better linear growth from birth to term equivalent age compared to the control group; mean difference in z score change from birth for length was 0.74 ([95% CI, 0.17-1.3]; p = 0.010). There were no differences in growth and body composition outcomes at 3 months corrected age between the groups. An increase in z score for weight after 36 weeks postmenstrual age and breastfeeding at 3 months corrected age were the strongest positive predictors of fat mass% at 3 months corrected age (both, p < 0.001). CONCLUSION: Early enhanced supplementation of ARA and DHA may be beneficial with respect to somatic growth in very preterm infants. CLINICAL TRIAL REGISTRATION: The trial has been registered on www. CLINICALTRIALS: gov, ID: NCT03555019.

Physical activity in childhood and later risk of inflammatory bowel disease: A Scandinavian birth cohort study.

BACKGROUND AND OBJECTIVE: Retrospective data have linked adult physical activity (PA) to reduced risk of inflammatory bowel disease (IBD). We aimed to prospectively examine the association of PA and screen time (ST) in childhood with later risk of IBD, for which data are scarce. METHODS: Using two population-based birth cohorts (All Babies in Southeast Sweden [ABIS] and Norwegian Mother, Father, and Child Cohort Study [MoBa]), we retrieved parent-reported data on PA and ST degree at ages 3 and 8 years. Data were modelled as binary (high vs. low) and numerical (hours/day) exposures. Inflammatory bowel disease was defined as ≥2 diagnostic records in national health registers. Cox regression estimated hazard ratios adjusted for potential confounding from parental IBD, country of origin, education, and smoking habits (Adjusted hazard ratio (aHR)). Our 8-year analyses included a 2-year lag period to reduce the risk of reverse causation. Cohort-specific estimates were pooled using random-effects model. RESULT: Among 65,978 participants from ABIS (n = 8810) and MoBa (n = 57,168) with available data, 266 developed IBD. At 3 years, children with high versus low PA had an aHR of 1.12 for IBD (95%CI = 0.87-1.43); high versus low ST showed an aHR of 0.91 (95%CI = 0.71-1.17). Conversely, at 8 years, high versus low ST was associated with increased risk of later IBD (aHR = 1.51; 95%CI = 1.02-2.25), but PA at 8 years, was not linked to IBD (aHR = 1.19; 95%CI = 0.80-1.76). Subtype-specific analyses for Crohn's disease and ulcerative colitis did not differ appreciably. CONCLUSION: Acknowledging possible confounding variables, children with high versus low ST at 8 years were at increased risk of IBD. In contrast, PA degree was not linked to IBD at any age category.

Childhood Socioeconomic Characteristics and Risk of Inflammatory Bowel Disease: A Scandinavian Birth Cohort Study.

BACKGROUND: Ecological observations suggest a negative relationship between childhood socioeconomic status (SES) and inflammatory bowel disease (IBD) risk. Individual-level analyses have been inconsistent and mostly lacked refined assessments of SES. We aimed to comprehensively study the association between early-life SES and later IBD. METHODS: This study included 117 493 participants from the Norwegian Mother, Father and Child cohort and Swedish All Babies in Southeast Sweden cohorts. Participants were followed from birth (1997-2009) through 2021. IBD was identified through national patient registers. Questionnaire and register data were used to define parental educational level, employment, and household income level. Cox regression estimated adjusted hazard ratios (aHRs), accounting for other SES exposures and covariates (eg, parental IBD). Cohort-specific estimates were pooled using a random-effects model. RESULTS: During 2 024 299 person-years of follow-up, 451 participants were diagnosed with IBD (All Babies in Southeast Sweden cohort, n = 113 and Norwegian Mother, Father and Child cohort, n = 338). Early-life maternal, but not paternal, educational level was associated with later IBD (low vs high educational level; pooled aHR, 1.81; 95% confidence interval [CI], 1.16-2.82; and pooled aHR, 1.20; 95% CI, 0.80-1.80; respectively). Having a nonworking mother or father was not significantly associated with IBD (pooled aHR, 0.69; 95% CI, 0.47-1.02; pooled aHR, 0.79; 95% CI, 0.45-1.37). High vs low household income level yielded a pooled aHR of 1.33 (95% CI, 0.94-1.89). Overall, results were largely consistent across cohorts. CONCLUSIONS: In this prospective Scandinavian cohort study, low maternal educational level was, independent of other SES and covariates, significantly associated with later IBD in her child. Further research is needed to elucidate factors that may mediate this relationship.

In this Scandinavian birth cohort study with ≥117 000 participants, we used prospectively collected data to investigate the association between early-life socioeconomic status and later inflammatory bowel disease. We found low maternal educational level, independent of covariates, negatively associated with inflammatory bowel disease.