Maternal and perinatal conditions and the risk of developing celiac disease during childhood

Effect of low birth weight and preterm delivery on the development of childhood celiac disease: a systematic review and meta-analysis on observational studies

PURPOSE OF REVIEW

Whether low birth weight (LBW) and preterm delivery (PD) are associated with the risk of developing celiac disease (CD) in children remains unclear. This systematic review and meta-analysis aimed to evaluate the association between LBW and PD with CD development in children.

RECENT FINDINGS

We searched PubMed, Embase, Scopus, Web of Science, and Google Scholar databases based on the Mesh terms to find observational studies that investigated the association of LBW and PD with CD development in children up to July 18, 2024. This systematic review was based on the PRISMA 2020 checklist. Heterogeneity between studies was assessed with Cochran's Q and I2 tests. Meta-regression was used to control heterogeneity. Publication bias was evaluated using Egger's test. Finally, ten studies involving 3 434 290 participants were included. Based on 10 studies, the pooled prevalence of LBW was 6.4 per 1000 children with CD. A pooled estimate of ten studies did not show a significant relationship between LBW and the risk of developing CD in children [odds ratio (OR): 0.96, 95% confidence interval (CI): 0.76, 1.16, I 2 : 67.9%, P : 0.001). Also, the pooled estimate of six studies did not show a significant relationship between PD and the risk of developing CD in children (OR: 0.98, 95% CI: 0.81, 1.16, I2 : 67.5%, P : 0.001).

SUMMARY

We found no evidence of an association between LBW and PD with the risk of developing CD in children.

Prevalence of celiac disease and its related factors in children aged 2-6 years old: A case-control study

Background: Celiac disease (CD) is an immune-genetic disorder associated with the small intestine. Aim: The aim of this study was to determine the prevalence of CD and its related factors in children aged 2-6 years in southeastern Iran. Methods: In the present case-control research, the study groups were selected by convenience sampling method in Zahedan city, Sistan-and-Baluchestan province, southeastern Iran, from January 2021 till January 2022. Social-demographic status and personal information about the child, family, as well as the feeding pattern of children and mothers in the first six months of breastfeeding were examined. Frequency Food Questionnaire (FFQ) was also used for data collection. Results: The prevalence of CD was estimated at 9.2 per 10,000. Our findings showed that child age, birth weight, location of living, child birth type, child digestive disease, and child FFQ score played a significant role in the development of CD (p < 0.05). Children with CD consumed less bread and cereals, meat, eggs and legumes, dairy products, and fruits and vegetables (p = 0.004). In the first six months of breastfeeding, the mean intake of mothers with celiac children and mothers with healthy children was almost the same (p = 0.75). Conclusion: Nutrition in the first six months of lactation, gastrointestinal diseases, birth weight, and type of delivery played a significant role in causing CD in children aged 2-6 years, but mothers' diets in the first six months of lactation had no significant effect on CD incidence in their infants.

Prevalence of delivery mode in an Italian nationwide cohort with celiac disease: a SIGENP multicenter retrospective study (the CD-deliver-IT)

BACKGROUND

Studies have indicated an association between cesarean section (CS), especially elective CS, and an increased risk of celiac disease (CD), but the conclusions of other studies are contradictory. The primary aim of this study (CD-deliver-IT) was to evaluate the rate of CS in a large population of CD patients throughout Italy.  METHODS: This national multicenter retrospective study was conducted between December 2020 and November 2021. The coordinating center was the Pediatric Gastroenterology and Liver Unit of Policlinico Umberto I, Sapienza, University of Rome, Lazio, Italy. Eleven other referral centers for CD have participated to the study. Each center has collected data on mode of delivery and perinatal period of all CD patients referring to the center in the last 40 years.

RESULTS

Out of 3,259 CD patients recruited in different Italian regions, data on the mode of delivery were obtained from 3,234. One thousand nine hundred forty-one (1,941) patients (60%) were born vaginally and 1,293 (40%) by CS (8.3% emergency CS, 30.1% planned CS, 1.5% undefined CS). A statistically significant difference was found comparing median age at time of CD diagnosis of patients who were born by emergency CS (4 years, CI 95% 3.40-4.59), planned CS (7 years, CI 95% 6.02-7.97) and vaginal delivery (6 years, CI 95% 5.62-6.37) (log rank p < 0.0001).

CONCLUSIONS

This is the first Italian multicenter study aiming at evaluating the rate of CS in a large population of CD patients through Italy. The CS rate found in our CD patients is higher than rates reported in the general population over the last 40 years and emergency CS seems to be associated with an earlier onset of CD compared to vaginal delivery or elective CS in our large nationwide retrospective cohort. This suggests a potential role of the mode of delivery on the risk of developing CD and on its age of onset, but it is more likely that it works in concert with other perinatal factors. Further prospective studies on other perinatal factors potentially influencing gut microbiota are awaited in order to address heavy conflicting evidence reaming in this research field.

How the Microbiota May Affect Celiac Disease and What We Can Do

Celiac disease (CeD) is an autoimmune disease with a strong association with human leukocyte antigen (HLA), characterized by the production of specific autoantibodies and immune-mediated enterocyte killing. CeD is a unique autoimmune condition, as it is the only one in which the environmental trigger is known: gluten, a storage protein present in wheat, barley, and rye. How and when the loss of tolerance of the intestinal mucosa to gluten occurs is still unknown. This event, through the activation of adaptive immune responses, enhances epithelial cell death, increases the permeability of the epithelial barrier, and induces secretion of pro-inflammatory cytokines, resulting in the transition from genetic predisposition to the actual onset of the disease. While the role of gastrointestinal infections as a possible trigger has been considered on the basis of a possible mechanism of antigen mimicry, a more likely alternative mechanism appears to involve a complex disruption of the gastrointestinal microbiota ecosystem triggered by infections, rather than the specific effect of a single pathogen on intestinal mucosal homeostasis. Several lines of evidence show the existence of intestinal dysbiosis that precedes the onset of CeD in genetically at-risk subjects, characterized by the loss of protective bacterial elements that both epigenetically and functionally can influence the response of the intestinal epithelium leading to the loss of gluten tolerance. We have conducted a literature review in order to summarize the current knowledge about the complex and in part still unraveled dysbiosis that precedes and accompanies CeD and present some exciting new data on how this dysbiosis might be prevented and/or counteracted. The literature search was conducted on PubMed.gov in the time frame 2010 to March 2024 utilizing the terms "celiac disease and microbiota", "celiac disease and microbiome", and "celiac disease and probiotics" and restricting the search to the following article types: Clinical Trials, Meta-Analysis, Review, and Systematic Review. A total of 364 papers were identified and reviewed. The main conclusions of this review can be outlined as follows: (1) quantitative and qualitative changes in gut microbiota have been clearly documented in CeD patients; (2) intestinal microbiota's extensive and variable interactions with enterocytes, viral and bacterial pathogens and even gluten combine to impact the inflammatory immune response to gluten and the loss of gluten tolerance, ultimately affecting the pathogenesis, progression, and clinical expression of CeD; (3) gluten-free diet fails to restore the eubiosis of the digestive tract in CeD patients, and also negatively affects microbial homeostasis; (4) new tools allowing targeted microbiota therapy, such as the use of probiotics (a good example being precision probiotics like the novel strain of B. vulgatus (20220303-A2) begin to show exciting potential applications.

Five-year follow-up of new cases after a coeliac disease mass screening

OBJECTIVE

We previously performed a population-based mass screening of coeliac disease in children aged 12 years in two birth cohorts resulting in 296 seropositive children, of whom 242 were diagnosed with coeliac disease after duodenal biopsies. In this follow-up study, we wanted to identify new cases in the screening population that tested negative-either converting from potential coeliac disease (seropositive but normal duodenal mucosa) or converting from seronegative at screening to diagnosed coeliac disease.

METHODS

All seropositive children were invited to a follow-up appointment 5 years after the screening with renewed serological testing and recommended endoscopic investigation if seropositive. Seronegative children in the screening study (n=12 353) were linked to the National Swedish Childhood Coeliac Disease Register to find cases diagnosed in healthcare during the same period.

RESULTS

In total, 230 (77%) came to the follow-up appointment, including 34 of 39 with potential coeliac disease. Of these, 11 (32%) had converted to coeliac disease. One new case was found in the National Swedish Childhood Coeliac Disease Register who received the diagnosis through routine screening in children with type 1 diabetes.

CONCLUSIONS

There is a high risk of conversion to coeliac disease among those with potential disease. However, a negative screening test was associated with a very low risk for a clinical diagnosis within a follow-up period of 5 years.

Cesarean delivery and risk of hospitalization for autoimmune disorders before 14 years of age

It is supposed that cesarean birth is implicated in the development of autoimmunity. We evaluated the association between cesarean delivery and the risk of hospitalization for autoimmune disease in children up to 14 years of age. We performed a longitudinal cohort study of 934,873 children born between 2006 and 2019 in Quebec, Canada. The main exposure measure was cesarean delivery versus vaginal delivery (spontaneous or induced). Outcomes included hospitalization for type 1 diabetes, celiac disease, or other autoimmune disorders before 14 years of age. We used Cox regression models to estimate hazard ratios (HR) and 95% confidence intervals (CI) for the association between cesarean delivery and hospitalization for autoimmune disorders, adjusted for patient characteristics. A total of 248,963 children (27%) were delivered by cesarean. Median length of follow-up was 7.4 years. The hospitalization rate for autoimmune disorders was 69.1 per 100,000 person-years for cesarean and 65.9 per 100,000 person-years for vaginal delivery. Cesarean delivery was not associated with autoimmune disorders overall (HR 1.02, 95% CI 0.96-1.10). There was no association with type 1 diabetes (HR 1.00, 95% CI 0.85-1.17), celiac disease (HR 0.86, 95% CI 0.71-1.04), inflammatory bowel disease (HR 1.15, 95% CI 0.88-1.49), or idiopathic thrombocytopenic purpura (HR 1.01, 95% CI 0.82-1.25). Cesarean delivery was not associated with autoimmune disorders at different ages.Conclusion: This study suggests that cesarean delivery is not associated with the risk of hospitalization for autoimmune disorders before 14 years of age. Delivery mode does not seem to mediate the risk of autoimmunity in childhood. What is Known: • Children born by cesarean may be at risk of abnormal immune development. • The association between cesarean delivery and risk of pediatric autoimmune disorders is unclear. What is New: • In this cohort study of over 900,000 children, cesarean delivery was not associated with the risk of hospitalization for a range of autoimmune disorders before 14 years of age. • Cesarean delivery may not be related to the development of autoimmunity.

Family socio-economic status and childhood coeliac disease seem to be unrelated-A cross-sectional screening study

Aim

The aim of our study was to examine whether there is a difference in coeliac disease prevalence in regard to parents' education level and occupation, and whether this differs between screened and clinically diagnosed children at the age of 12 years.

Methods

The study, Exploring the Iceberg of Celiacs in Sweden (ETICS), was a school‐based screening study of 12‐year‐old children that was undertaken during the school years 2005/2006 and 2009/2010. Data on parental education and occupation were reported from parents of the children. Specifically, by parents of 10 710 children without coeliac disease, 88 children diagnosed with coeliac disease through clinical care, and 231 who were diagnosed during the study.

Results

There were no statistically significant associations between occupation and coeliac disease for either the clinically detected (prevalence ratio 1.16; confidence interval 0.76‐1.76) or screening‐detected coeliac disease cases (prevalence ratio 0.86; confidence interval 0.66‐1.12) in comparison with children with no coeliac disease. Also, there were no statistically significant associations for parental education and coeliac disease diagnosis.

Conclusion

There was no apparent relationship between coeliac disease and socio‐economic position. Using parents' socio‐economic status as a tool to help identify children more likely to have coeliac disease is not recommended.

Role of the gut microbiota in the pathogenesis of coeliac disease and potential therapeutic implications

PURPOSE

Although genetic predisposition and exposure to dietary gluten are considered necessary triggers for the development of coeliac disease, alterations in the gut microbial composition may also contribute towards the pathogenesis of coeliac disease. This review aims to provide an overview of the available data on the potential mechanisms through which the gut microbiota plays a role in the causation of coeliac disease and to discuss the potential therapeutic strategies that could diminish the consequences of microbial dysbiosis.

METHOD

A search of the literature was performed using the PubMed, Embase, and JSTOR databases; relevant articles were included.

RESULTS

Recent studies in patients with coeliac disease have reported an increase in the relative amounts of gram negative bacterial genera such as Bacteroides, Prevotella, and Escherichia, and reduced amounts of protective anti-inflammatory bacteria such as Bifidobacteria and Lactobacilli. Dysbiotic microbiota may lead to a dysregulated immune response that may contribute to the pathogenesis of coeliac disease. In infancy, antibiotic use and certain infant feeding practices may lead to alterations in the developing gut microbiota to influence the immune maturation process and predispose to coeliac disease.

CONCLUSION

The induction of the intestinal immune system and gluten intolerance may be influenced by the relative abundance of certain microbiota. Factors such as infant feeding practices, diet, antibiotics, and infections, may be involved in the development of coeliac disease due to their influence on gut microbial composition. The efficacy of potential modulators of the gut microbiota such as probiotics, prebiotics, and fecal microbial transplant as adjunctive treatments to gluten-free diet in coeliac disease is unproven and requires further investigation.

Childhood disability and its associated perinatal characteristics in Bao'an district of Shenzhen, China

BACKGROUND

Disability has become a public health issues in China and around the world. This study aimed to report prevalence of children with disability by gender, delivery mode, birth weight, gestational age, birth defect and impairment type in the past 15 years in Baoan District, Shenzhen.

METHODS

Data of children with all types of disability from year 2004 to 2018 was obtained from the registry database of Baoan Disabled Persons Federation. Their perinatal information, including gender, delivery mode, birth weight, gestational age, birth defect were traced from Shenzhen Maternal and Child Health Management System and compared with the whole registered population live births information in this district. Data of children with disabilities were included to calculate the prevalence (%).

RESULTS

An overall prevalence of children disability was 1.02% in Baoan district, Shenzhen, in the past 15 years. The overall as well as mental disability prevalence rose from the first 5 years period (2004 to 2008) to the second 5 years of 2009 to 2013, and then dropped to the lowest level in the third 5 year of 2014-2018. Mental disability and intelligent disability accounted for the highest proportion. More than 70% of all kinds of the disabilities except mental disability were detected before 1 year old, 87% of the mental and intelligent disabilities were found before 3 years old. The Percentages of male, premature, low birth weight infants and children with cesarean, birth defect in disable children were higher than in whole population live birth children.

CONCLUSIONS

The overall prevalence of disability declined in the district after specific policy engagement. Mental and intelligent disabilities were still the most common disability in the district. The age of 0-3 years was an important period for early childhood detection and intervention.

Incidence of Celiac Disease Is Increasing Over Time: A Systematic Review and Meta-analysis

OBJECTIVES

To conduct a systematic review and meta-analysis that defines the worldwide incidence of celiac disease (CD) and examines temporal trends.

METHODS

MEDLINE and EMBASE were searched for population-based studies reporting the incidence of CD in the overall population, children, or adults. No limits were placed on year or language of publication. Studies solely examining at-risk populations (e.g., patients with type 1 diabetes) were excluded. Random-effects models were performed to meta-analyze sex- and age-specific incidence in the 21st century. Temporal trend analyses assessed the average annual percent change in CD incidence over time.

RESULTS

Of 11,189 citations, 86 eligible studies were identified for inclusion, of which 50 were deemed suitable for analyses. In the 21st century, the pooled female incidence of CD was 17.4 (95% confidence interval [CI]: 13.7, 21.1) (I = 99.5%) per 100,000 person-years, compared with 7.8 (95% CI: 6.3, 9.2) (I = 98.6%) in males. Child-specific incidence was 21.3 per 100,000 person-years (95% CI: 15.9, 26.7) (I = 99.7%) compared with 12.9 (95% CI: 7.6, 18.2) (I = 99.9%) in adults. Pooling average annual percent changes showed the incidence of CD to be increasing by 7.5% (95% CI: 5.8, 9.3) (I = 79.6%) per year over the past several decades.

DISCUSSION

Incidence of CD is highest in females and children. Overall, the incidence has been significantly rising in the latter half of the 20th century and into the 21st century throughout the Western world. Population-based studies in Africa, Asia, and Latin America are needed to provide a comprehensive picture of the global incidence of CD.

The Gut Microbiota in Celiac Disease and probiotics

Celiac disease (CeD) is an immune-mediated enteropathy, and unique in that the specific trigger is known: gluten. The current mainstay of therapy is a gluten-free diet (GFD). As novel therapies are being developed, complementary strategies are also being studied, such as modulation of the gut microbiome. The gut microbiota is involved in the initiation and perpetuation of intestinal inflammation in several chronic diseases. Intestinal dysbiosis has been reported in CeD patients, untreated or treated with GFD, compared to healthy subjects. Several studies have identified differential bacterial populations associated with CeD patients and healthy subjects. However, it is still not clear if intestinal dysbiosis is the cause or effect of CeD. Probiotics have also been considered as a strategy to modulate the gut microbiome to an anti-inflammatory state. However, there is a paucity of data to support their use in treating CeD. Further studies are needed with therapeutic microbial formulations combined with human trials on the use of probiotics to treat CeD by restoring the gut microbiome to an anti-inflammatory state.

Potential risk factors for celiac disease in childhood: a case-control epidemiological survey

Background: Celiac disease (CD) prevalence has increased significantly in recent decades in some developed countries. Yet the environmental factors in the existing literature do not appear to provide a satisfactory explanation for this increase.

Objective: To determine whether nine variables are associated with CD in children. These variables are: incidence of ear infection before 2 years old, courses of antibiotics before 2 years old, duration of breastfeeding, vitamin D drop exposure in infancy, vitamin D supplement exposure between 2–3 years old, age at gluten introduction into the diet, fat content of cow’s milk consumed between 2–3 years old, quantity of cow’s milk consumed between 2–3 years old, and type of water consumed at 2 years old.

Methods: An Internet-based survey was conducted among parents living in the US with at least one biological child between 3 and 12 years old. Potential participants were informed about the survey through social media, websites, electronic newsletters, and advertisements.

Results: After exclusions, there remained 332 responses associated with children with CD (cases), and 241 responses associated with children who do not have CD (controls). In this data set, skim milk as the primary form of liquid cow’s milk consumed between 2–3 years old (adjusted odds ratio [aOR]=3.556, CI=1.430–10.22, P=0.010), vitamin D drops administered for more than 3 months (aOR=1.749, CI=1.079–2.872, P=0.025), courses of antibiotics (aOR=1.133, CI=1.037–1.244, P=0.007), and incidence of ear infection (aOR=1.183, CI=1.041–1.348, P=0.010) are all associated with CD in children.

Conclusions: This study is the first to find an association between skim milk consumption and CD and vitamin D drop use for greater than 3 months and CD. It also adds to evidence that early life exposure to antibiotics and early life infection, specifically ear infection, are associated with CD.

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Smoking in pregnancy, cord blood cotinine and risk of celiac disease diagnosis in offspring

Ecological observations suggest an inverse relationship between smoking in pregnancy and celiac disease (CD) in offspring. While individual-level analyses have been inconsistent, they have mostly lacked statistical power or refined assessments of exposure. To examine the association between pregnancy-related smoking and CD in the offspring, as well as its consistency across data sets, we analyzed: (1) The Norwegian Mother and Child Cohort (MoBa) of 94,019 children, followed from birth (2000–2009) through 2016, with 1035 developing CD; (2) a subsample from MoBa (381 with CD and 529 controls) with biomarkers; and (3) a register-based cohort of 536,861 Norwegian children, followed from birth (2004–2012) through 2014, with 1919 developing CD. Smoking behaviors were obtained from pregnancy questionnaires and antenatal visits, or, in the MoBa-subsample, defined by measurement of cord blood cotinine. CD and potential confounders were identified through nationwide registers and comprehensive parental questionnaires. Sustained smoking during pregnancy, both self-reported and cotinine-determined, was inversely associated with CD in MoBa (multivariable-adjusted [a] OR = 0.61 [95%CI, 0.46–0.82] and aOR = 0.55 [95%CI, 0.31–0.98], respectively); an inverse association was also found with the intensity of smoking. These findings differed from those of our register-based cohort, which revealed no association with sustained smoking during pregnancy (aOR = 0.97 [95%CI, 0.80–1.18]). In MoBa, neither maternal smoking before or after pregnancy, nor maternal or paternal smoking in only early pregnancy predicted CD. In a carefully followed pregnancy cohort, a more-detailed smoking assessment than oft-used register-based data, revealed that sustained smoking during pregnancy, rather than any smoking exposure, predicts decreased likelihood of childhood-diagnosed CD.

Dietary Patterns After the Weaning and Lactation Period Are Associated With Celiac Disease Autoimmunity in Children

BACKGROUND & AIMS

There have been many studies of associations between infant feeding practices and development of celiac disease during childhood, but few studies have focused on overall diets of young children after the weaning period. We aimed to examine the association between common dietary patterns in infants and the occurrence of celiac disease autoimmunity during childhood.

METHODS

We performed a prospective analysis of data from the Generation R Study that comprised 1997 children born from April 2002 through January 2006 in Rotterdam, the Netherlands. Food consumption around 1 year of age was assessed with a validated food-frequency questionnaire. Dietary data were examined using a priori (based on existing guidelines) and a posteriori (principal component analysis and reduced rank regression) dietary pattern analyses. Five dietary patterns were compared. Celiac disease autoimmunity, determined on the basis of serum concentration of transglutaminase-2 autoantibody (ie, TG2A) below or above 7 U/mL, was evaluated at 6 years. Associations between dietary pattern adherence scores and celiac disease autoimmunity were examined using multivariable logistic regression models.

RESULTS

Higher adherence to the a posteriori-derived prudent dietary pattern (high intake of vegetables, vegetable oils, pasta, and grains and low consumption of refined cereals and sweet beverages) at 1 year was significantly associated with lower odds of celiac disease autoimmunity at 6 years (odds ratio, 0.67; 95% confidence interval, 0.53-0.84). No significant associations were found for the 4 remaining dietary patterns.

CONCLUSIONS

In a prospective study of dietary patterns of young children in the Netherlands, we associated a dietary pattern characterized by high consumption of vegetables and grains and low consumption of refined cereals and sweet beverages, with lower odds of celiac disease autoimmunity. Early-life dietary patterns might therefore be involved in the development of celiac disease during childhood.

Mode of delivery is not associated with celiac disease

Purpose

The purpose of this study was to investigate the association between mode of delivery and the risk of celiac disease in two large population-based birth cohorts with different prevalence of diagnosed celiac disease.

Patients and methods

This is an observational register-based cohort study using two independent population cohorts. We used data from administrative registers and health administrative registers from Denmark and Norway and linked the data at the individual level. We included all children who were born in Denmark from January 1, 1995 to December 31, 2010 and all children who were born in Norway from January 1, 2004 to December 31, 2012.

Results

We included 1,051,028 children from Denmark. Cesarean sections were registered for 196,512 children (18.9%). Diagnosed celiac disease was registered for 1,395 children (0.13%). We included 537,457 children from Norway. Cesarean sections were registered for 90,128 children (16.8%). Diagnosed celiac disease was registered for 1,919 children (0.35%). We found no association between the mode of delivery and the risk of diagnosed celiac disease. The adjusted odds ratio for celiac disease for children delivered by any type of cesarean section compared to vaginal delivery was 1.11 (95% CI: 0.96–1.29) in the Danish cohort and 0.96 (95% CI: 0.84–1.09) in the Norwegian cohort. The adjusted odds ratio for celiac disease for children delivered by elective cesarean section compared to vaginal delivery was 1.20 (95% CI: 1.00–1.43) in the Danish cohort and 0.96 (95% CI: 0.79–1.17) in the Norwegian cohort.

Conclusion

In this large registry-based study, mode of delivery was not associated with an increased risk of diagnosed celiac disease.

Effect of childhood coeliac disease on ninth grade school performance: evidence from a population-based study

BACKGROUND

Coeliac disease might affect school performance due to its effect on cognitive performance and related health consequences that might increase school absenteeism. The aim of this study was to investigate whether children with coeliac disease performed differently on completion of ninth grade in school compared with children without coeliac disease.

METHODS

Analysis was performed on a population of 445 669 children born in Sweden between 1991 and 1994 of whom 1767 were diagnosed with coeliac disease. School performance at ninth grade was the outcome and coeliac disease was the exposure. Other covariates included sex, Apgar score at 5 min, small for gestational age, year of birth, family type, parental education and income.

RESULTS

There was no association between coeliac disease and school performance at ninth grade (adjusted coefficient -2.4, 95% CI 5.1 to 0.4). A weak association was established between late coeliac diagnosis and higher grades, but this disappeared after adjusting for parent socioeconomic conditions. Being small for gestational age affected performance negatively (adjusted coefficient -6.9, 95% CI 8.0 to 5.7). Grade scores were significantly lower in children living with a single parent (adjusted coefficient -20.6, 95% CI 20.9 to 20.2), compared with those with married/cohabiting parents. A positive association was found between scores at ninth grade and parental education and income.

CONCLUSION

Coeliac disease diagnosis during childhood is not associated with poor school performance at ninth grade.

Birth weight, sex, and celiac disease: a nationwide twin study

OBJECTIVE

Earlier research suggests that birth weight may be associated with celiac disease (CD), but the direction of association has been unclear potentially due to confounding effect from genetic and intrafamilial factors. Through within-twin analyses, we aimed to minimize confounding effects such as twins that share genetic and early environmental exposures.

MATERIALS AND METHODS

Using the Swedish Twin Registry, we examined the birth weight of 146,830 twins according to the CD status. CD was defined as having villous atrophy according to a small intestinal biopsy reports.

RESULTS

The prevalence of diagnosed CD was 0.5% (n=669), and we included 407 discordant pairs of CD-non-CD twins. Comparing the 669 CD patients with non-CD twins, the association between birth weight and future CD was not statistically significant (odds ratio [OR] per 1000 g increase in birth weight: 1.16; 95% confidence interval [CI]=0.97-1.38). In males, the association was positive and statistically significant (OR=1.50; 95% CI=1.11-2.02). However, the association was not significant in within-pair analyses for both dizygotic and monozygotic twins and for both sexes.

CONCLUSION

This population-based study found that in male twins, higher birth weight was associated with higher risk of CD. However, when comparing discordant twin pairs in within-twin pair analyses, there was no statistically significant association between birth weight, intrauterine growth, and future risk of CD.

Towards non-conventional methods of designing register-based epidemiological studies: An application to pediatric research

AIMS

Various epidemiological designs have been applied to investigate the causes and consequences of fetal growth restriction in register-based observational studies. This review seeks to provide an overview of several conventional designs, including cohort, case-control and more recently applied non-conventional designs such as family-based designs. We also discuss some practical points regarding the application and interpretation of family-based designs.

METHODS

Definitions of each design, the study population, the exposure and the outcome measures are briefly summarised. Examples of study designs are taken from the field of low birth-weight research for illustrative purposes. Also examined are relative advantages and disadvantages of each design in terms of assumptions, potential selection and information bias, confounding and generalisability. Kinship data linkage, statistical models and result interpretation are discussed specific to family-based designs.

RESULTS

When all information is retrieved from registers, there is no evident preference of the case-control design over the cohort design to estimate odds ratios. All conventional designs included in the review are prone to bias, particularly due to residual confounding. Family-based designs are able to reduce such bias and strengthen causal inference. In the field of low birth-weight research, family-based designs have been able to confirm a negative association not confounded by genetic or shared environmental factors between low birth weight and the risk of asthma.

CONCLUSIONS

We conclude that there is a broader need for family-based design in observational research as evidenced by the meaningful contributions to the understanding of the potential causal association between low birth weight and subsequent outcomes.

Strategies to improve the efficiency of celiac disease diagnosis in the laboratory

The demand for testing to detect celiac disease (CD) autoantibodies has increased, together with the cost per case diagnosed, resulting in the adoption of measures to restrict laboratory testing. We designed this study to determine whether opportunistic screening to detect CD-associated autoantibodies had advantages compared to efforts to restrict testing, and to identify the most cost-effective diagnostic strategy. We compared a group of 1678 patients in which autoantibody testing was restricted to cases in which the test referral was considered appropriate (G1) to a group of 2140 patients in which test referrals were not reviewed or restricted (G2). Two algorithms A (quantifying IgA and Tissue transglutaminase IgA [TG-IgA] in all patients), and B (quantifying only TG-IgA in all patients) were used in each group, and the cost-effectiveness of each strategy was calculated. TG-IgA autoantibodies were positive in 62 G1 patients and 69 G2 patients. Among those positive for tissue transglutaminase IgA and endomysial IgA autoantibodies, the proportion of patients with de novo autoantibodies was lower (p=0.028) in G1 (11/62) than in G2 (24/69). Algorithm B required fewer determinations than algorithm A in both G1 (2310 vs 3493; p<0.001) and G2 (2196 vs 4435; p<0.001). With algorithm B the proportion of patients in whom IgA was tested was lower (p<0.001) in G2 (29/2140) than in G1 (617/1678). The lowest cost per case diagnosed (4.63 euros/patient) was found with algorithm B in G2. We conclude that opportunistic screening has advantages compared to efforts in the laboratory to restrict CD diagnostic testing. The most cost-effective strategy was based on the use of an appropriate algorithm.

Maternal and neonatal vitamin D status, genotype and childhood celiac disease

Background

Low concentration of 25-hydroxyvitamin D during pregnancy may be associated with offspring autoimmune disorders. Little is known about environmental triggers except gluten for celiac disease, a common immune-mediated disorder where seasonality of birth has been reported as a risk factor. We therefore aimed to test whether low maternal and neonatal 25-hydroxyvitamin D predicted higher risk of childhood celiac disease.

Methods and Findings

In this Norwegian nationwide pregnancy cohort (n = 113,053) and nested case-control study, we analyzed 25-hydroxyvitamin D in maternal blood from mid-pregnancy, postpartum and cord plasma of 416 children who developed celiac disease and 570 randomly selected controls. Mothers and children were genotyped for established celiac disease and vitamin D metabolism variants. We used mixed linear regression models and logistic regression to study associations.

There was no significant difference in average 25-hydroxyvitamin D between cases and controls (63.1 and 62.1 nmol/l, respectively, p = 0.28), and no significant linear trend (adjusted odds ratio per 10 nM increase 1.05, 95% CI: 0.93–1.17). Results were similar when analyzing the mid-pregnancy, postpartum or cord plasma separately. Genetic variants for vitamin D deficiency were not associated with celiac disease (odds ratio per risk allele of the child, 1.00; 95% CI, 0.90 to 1.10, odds ratio per risk allele of the mother 0.94; 95% CI 0.85 to 1.04). Vitamin D intake in pregnancy or by the child in early life did not predict later celiac disease. Adjustment for established genetic risk markers for celiac disease gave similar results.

Conclusions

We found no support for the hypothesis that maternal or neonatal vitamin D status is related to the risk of childhood celiac disease.

Recent advances in pediatric celiac disease

The incidence of celiac disease (CD) has increased over the last half-century, resulting in rising interest in identifying risk factors for CD. The necessity of duodenal biopsies in the diagnosis of CD has recently been challenged. Areas covered: This review covers the recent literature regarding the role of infant feeding practices, including breastfeeding and timing of gluten introduction, and the microbiota in the development of CD. Additionally, the application of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition guidelines for a non-biopsy approach to the diagnosis of CD is reviewed. Expert commentary: Recent investigations have not revealed any significant effect of breastfeeding or timing of gluten introduction on the risk of CD in at-risk populations. There are alterations in the microbiota of CD patients. However, the role of the microbiome and whether its manipulation has a clinical effect are unknown. Preliminary data suggests a non-biopsy approach to diagnosis of pediatric CD can be applied to several populations, although additional studies are needed. Prospective investigations are underway to examine the interplay of infant feeding practices and the microbiome and to identify particular CD-specific biomarkers that may aid in the diagnosis and ultimately prevention of CD.

Validation of celiac disease diagnoses recorded in the Danish National Patient Register using duodenal biopsies, celiac disease-specific antibodies, and human leukocyte-antigen genotypes

Purpose

The purpose of this study was to validate the celiac disease diagnoses recorded in the Danish National Patient Register. To validate the diagnoses, we used information on duodenal biopsies from a national register of pathology reports (the Patobank) and information on celiac disease-specific antibodies and human leukocyte antigen (HLA) genotypes obtained from patient medical records.

Patients and methods

We included all the children who were born from 1995 to 2012 and who were registered as having celiac disease in the Danish National Patient Register. We reviewed all the pathology reports on duodenal biopsies in the Patobank and the information in the medical records on celiac disease-specific antibodies (ie, anti-tissue transglutaminase 2 IgA and IgG, endomysial antibodies IgA, and anti-deamidated gliadin peptide IgG) and HLA genotypes.

Results

We identified 2,247 children who were registered in the Danish National Patient Register with celiac disease. Duodenal biopsies for 1,555 of the children (69%) were registered in the Patobank; 1,127 (50%) had a biopsy that was compatible with celiac disease (ie, Marsh 2–3). We accessed the medical records of 95% of the children who were registered in the Danish National Patient Register with celiac disease. We found that 1,510 (67%) had one or more positive antibody-test results; 1,120 (50%) had anti-tissue transglutaminase 2, IgA at tenfold or greater the upper limit of the normal range and/or positive endomysial antibody results. The positive predictive value depended on the criteria used for validation and the types and numbers of registrations that were included in the analysis and ranged from 62% (95% confidence interval: 60%–64%) to 86% (95% confidence interval: 84%–87%).

Conclusion

Our findings indicate that the Danish National Patient Register is a valuable source to identify patients who have been diagnosed with celiac disease. However, validation of the diagnoses is warranted before data on the patients are used for research purposes.