Significant effects of childhood obesity treatment with a web-based component in a randomised controlled study (Web-COP).

AIM: We evaluated the effect on body mass index standard deviation score (BMI-SDS) of a combined treatment (Web-COP) for children with obesity, including a web-based component targeting their parents. METHODS: This randomised controlled trial recruited children 5-12 years of age with obesity (International Obesity Task Force BMI [IOTF-BMI] ≥30 kg/m2 ) from school health care and outpatient paediatric clinics in in Northern Sweden from 1 June 2019 to 21 June 2020. The children were randomised to Web-COP, an intervention with group sessions and a 12-week web-based component, or standard care. The primary outcome was the change in IOTF BMI-SDS after 6 months. RESULTS: In total, 75 children (33 girls), mean age 9.5 years, were randomised, and 65/75 (87%) children and their parents completed the study, 35/39 (90%) in the Web-COP intervention and 30/36 (83%) in the standard care group. BMI-SDS at 6 months was changed from 3.08 to 2.81 in the intervention group compared to an increase from 3.07 to 3.16 in the standard care group, representing a significant difference between groups (p < 0.001). In the intervention group, 14/30 (47%) reduced their BMI-SDS ≥0.25, compared to none in the standard care group. CONCLUSION: The parent-focused intervention significantly improved BMI-SDS in children with obesity as compared to children in standard care.

Identification of Childhood-Onset Inflammatory Bowel Disease in Swedish Healthcare Registers: A Validation Study.

Purpose: The Swedish National Patient Register (NPR) is often used in observational studies of childhood-onset inflammatory bowel disease (IBD) (<18 years of age) and its subtypes, but the validity of previously used register-based algorithms for capturing childhood-onset IBD has never been examined. Methods: We identified a random sample of 233 individuals with at least two first ever diagnostic listings of IBD in the NPR between 2002 and 2014. We calculated the test characteristics for different register-based definitions of IBD and its subtypes using the Copenhagen criteria and the revised Porto criteria as gold standard, both based on medical chart review. We made assumptions of the occurrence of undiagnosed IBD in the general child population based on available literature. Results: Out of 233 individuals with at least two diagnostic listings of IBD, 216 had true IBD, resulting in a positive predictive value (PPV) = 93% (95% confidence interval (CI) 89-96), sensitivity = 88% (95% CI 83-92), specificity = 100% (95% CI 100-100), and negative predictive value (NPV) = 100% (95% CI 100-100). The PPV for the NPR-based definitions of IBD subtypes at time of first IBD diagnosis and at end of follow-up were 78% (95% CI 69-86) and 88% (95% CI 80-94), respectively, for Crohn's disease and 74% (95% CI 63-83) and 71% (95% CI 60-80), respectively, for ulcerative colitis. Conclusion: The validity of register-based definitions of childhood-onset IBD in the Swedish NPR is high and can be used to identify patients in observational research.

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.

Is mass screening for coeliac disease a wise use of resources? A health economic evaluation.

BACKGROUND: Living with undiagnosed symptomatic coeliac disease is connected with deteriorated health, and persons with coeliac disease often wait a long time for their diagnosis. A mass screening would lower the delay, but its cost-effectiveness is still unclear. Our aim was to determine the cost-effectiveness of a coeliac disease mass screening at 12 years of age, taking a life course perspective on future benefits and drawbacks. METHODS: The cost-effectiveness was derived as cost per quality-adjusted life-year (QALY) using a Markov model. As a basis for our assumptions, we mainly used information from the Exploring the Iceberg of Celiacs in Sweden (ETICS) study, a school-based screening conducted in 2005/2006 and 2009/2010, where 13,279 12-year-old children participated and 240 were diagnosed with coeliac disease, and a study involving members of the Swedish Coeliac Association with 1031 adult participants. RESULTS: The cost for coeliac disease screening was 40,105 Euro per gained QALY. Sensitivity analyses support screening based on high compliance to a gluten-free diet, rapid progression from symptom-free coeliac disease to coeliac disease with symptoms, long delay from celiac disease with symptoms to diagnosis, and a low QALY score for undiagnosed coeliac disease cases. CONCLUSIONS: A coeliac disease mass screening is cost-effective based on the commonly used threshold of 50,000 Euro per gained QALY. However, this is based on many assumptions, especially regarding the natural history of coeliac disease and the effects on long-term health for individuals with coeliac disease still eating gluten.

Questionnaire showed that Swedish paediatric clinics complied well with the revised European guidelines for diagnosing coeliac disease.

AIM: In 2012, revised criteria for diagnosing childhood coeliac disease were published by the European Society for Paediatric Gastroenterology, Hepatology and Nutrition and incorporated into the revised Swedish guidelines the same year. These made it possible, in certain cases, to diagnose coeliac disease without taking small bowel biopsies. This survey assessed the extent to which the new guidelines were implemented by Swedish paediatric clinics two years after their introduction. METHODS: In October 2014, we distributed a paper questionnaire including five questions on diagnostic routines to the 40 paediatric clinics in university or regional hospitals in Sweden that perform small bowel biopsies. RESULTS: All 36 (90%) clinics that responded used anti-tissue transglutaminase antibodies as the initial diagnostic test and some also used serological markers. Most clinics (81%) used endoscopy and took multiple duodenal biopsies, whereas only a few (19%) occasionally employed a suction capsule. Almost all clinics (86%) omitted taking small bowel biopsies in symptomatic children with repeatedly high coeliac serology and positive genotyping, thereby avoiding the need for invasive endoscopy under anaesthesia. CONCLUSION: The 2012 Swedish Paediatric Coeliac Disease Diagnostic Guidelines had been widely accepted and implemented in routine health care two years after their introduction.

Immunopathology of childhood celiac disease-Key role of intestinal epithelial cells.

BACKGROUND & AIMS: Celiac disease is a chronic inflammatory disease of the small intestine mucosa due to permanent intolerance to dietary gluten. The aim was to elucidate the role of small intestinal epithelial cells in the immunopathology of celiac disease in particular the influence of celiac disease-associated bacteria. METHODS: Duodenal biopsies were collected from children with active celiac disease, treated celiac disease, and clinical controls. Intestinal epithelial cells were purified and analyzed for gene expression changes at the mRNA and protein levels. Two in vitro models for human intestinal epithelium, small intestinal enteroids and polarized tight monolayers, were utilized to assess how interferon-γ, interleukin-17A, celiac disease-associated bacteria and gluten influence intestinal epithelial cells. RESULTS: More than 25 defense-related genes, including IRF1, SPINK4, ITLN1, OAS2, CIITA, HLA-DMB, HLA-DOB, PSMB9, TAP1, BTN3A1, and CX3CL1, were significantly upregulated in intestinal epithelial cells at active celiac disease. Of these genes, 70% were upregulated by interferon-γ via the IRF1 pathway. Most interestingly, IRF1 was also upregulated by celiac disease-associated bacteria. The NLRP6/8 inflammasome yielding CASP1 and biologically active interleukin-18, which induces interferon-γ in intraepithelial lymphocytes, was expressed in intestinal epithelial cells. CONCLUSION: A key factor in the epithelial reaction in celiac disease appears to be over-expression of IRF1 that could be inherent and/or due to presence of undesirable microbes that act directly on IRF1. Dual activation of IRF1 and IRF1-regulated genes, both directly and via the interleukin-18 dependent inflammasome would drastically enhance the inflammatory response and lead to the pathological situation seen in active celiac disease.

Season and region of birth as risk factors for coeliac disease a key to the aetiology?

BACKGROUND: Coeliac disease (CD) incidence has increased in recent decades, characterised by variations according to sex, age at diagnosis, year of birth, month of birth and region of birth. Genetic susceptibility and exposure to gluten are the necessary factors in CD aetiology, although several environmental factors are considered. METHODS: A nationwide prospective cohort longitudinal study was conducted consisting of 1 912 204 children aged 0-14.9 years born in Sweden from 1991 to 2009. A total of 6569 children were diagnosed with biopsy-verified CD from 47 paediatric departments. Using Cox regression, we examined the association between CD diagnosis and season of birth, region of birth and year of birth. RESULTS: Overall, CD risk was higher for children born during spring, summer and autumn as compared with children born during winter: adjusted HR for spring 1.08 (95% CI 1.01 to 1.16), summer 1.10 (95% CI 1.03 to 1.18) and autumn 1.10 (95% CI 1.02 to 1.18). Increased CD risk was highest if born in the south, followed by central Sweden when compared with children born in northern Sweden. Children diagnosed at <2 years had an increased CD risk if born in spring while those diagnosed at 2-14.9 years the risk was increased for summer and autumn births. The birth cohort of 1991-1996 had increased CD risk if born during spring, for the 1997-2002 birth cohort the risk increased for summer and autumn births, while for the birth cohort of 2003-2009 the risk was increased if born during autumn. CONCLUSIONS: Season of birth and region of birth are independently and jointly associated with increased risk of developing CD during the first 15 years of life. Seasonal variation in infectious load is the likely explanation.

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

BACKGROUND: Celiac disease (CD) is increasing worldwide, which might be due to the changing environmental and lifestyle exposures. We aimed to explore how conditions related to maternity, delivery and the neonatal period influence CD onset during childhood. METHODS: Using Sweden's national registers we had access to information on 1 912 204 children born between 1991 and 2009, 6 596 of whom developed CD before 15 years of age. Logistic regression analyses were performed to determine how CD is associated with maternity, delivery and the neonatal period. RESULTS: Regardless of sex, a reduction in CD risk was observed in children born to mothers aged ≥35 years (odds ratio [OR] 0.8; 95 % confidence interval [CI] 0.7-0.9) and with high maternal income (OR 0.9; 95 % CI 0.8-0.9). Being a second-born child, however, was positively associated with CD. Among boys, elective caesarean delivery increased the risk of CD (OR 1.2; 95 % CI 1.0-1.4), while maternal overweight (OR 0.9; 95 % CI 0.8-0.9), premature rupture of the membrane (OR 0.4; 95 % CI 0.2-0.8) and low birth weight showed a negative association. Girls had an increased CD risk compared to boys and in girls the risk was increased by repeated maternal urinary tract infections (OR 1.1; 95 % CI 1.0-1.2). CONCLUSIONS: Elective caesarean delivery and repeated maternal urinary tract infections during pregnancy are associated with increased risk of CD onset during childhood, suggesting the role of dysbiosis during early life. High maternal age and high income reduced the risk of CD, which might be due to infant-feeding practices and life style.

Celiac disease can be predicted by high levels of anti-tissue transglutaminase antibodies in population-based screening.

OBJECTIVES: The aim of the present study was to evaluate any potential correlation between anti-tissue transglutaminase antibodies of type immunoglobulin A (tTG-IgA) and the degree of gluten-induced enteropathy in children participating in a screening study for celiac disease (CD) and to assess to what extent the revised European Society for Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) guidelines cover this group of patients. METHODS: The present study is a substudy of a cross-sectional CD screening study, Exploring the Iceberg of Celiacs in Sweden, a 2-phased study performed during 2005 to 2006 and 2009 to 2010. The 13,279 participating children had a blood test obtained, and those with positive tTG-IgA were recommended a small intestinal biopsy. The tTG-IgA levels at the time of biopsy were compared with those at the assessment of the biopsy. RESULTS: There were 267 children included, of whom 230 were diagnosed as having CD. Of all of the children, 67 children had low tTG-IgA levels (<5 U/mL), of whom 55% had Marsh 3 lesions. All of the children with tTG-IgA levels exceeding 10 times the upper limit of normal values of 5 U/mL, that is, 50 U/mL, were diagnosed as having CD. Lowering the cutoff to 3 U/mL, all but 1 child with 30 U/mL got CD diagnosis. CONCLUSIONS: By adopting the revised ESPGHAN criteria, biopsies could have been omitted in one-fourth of all of the patients. Our results indicate that the criteria may be useful even in screened children. Further studies are needed to confirm whether the 2012 ESPGHAN guidelines should be revised to also apply to the populations being screened.

High adherence to a gluten-free diet in adolescents with screening-detected celiac disease.

OBJECTIVES: The aim of the study was to evaluate the gluten-free diet (GFD) adherence after 1 year of follow-up in children with screening-detected celiac disease (CD) in a general population. METHODS: A total of 18,325 twelve-year-olds were invited to participate in a population-based CD screening (Exploring the Iceberg of Celiacs in Sweden), of whom 13,279 participated. In 240 children, CD was detected through elevated anti-tissue transglutaminase antibodies 2 (TG2-IgA) and verified by a small-intestinal biopsy. This substudy included 210 children with TG2-IgA, evaluated both at the initial biopsy occasion and at 1-year follow-up. GFD adherence was evaluated by a combination of TG2-IgA measurements and self-reported adherence (n = 193). RESULTS: After 1 year, 85% (179/210) had normalized TG2-IgA levels (<5 U/mL). Among those who had >50 U/mL at diagnosis, 25% (16/63) still had elevated TG2-IgA, but for the majority their initial values were more than halved. Most reported a high level of GFD adherence ("always" 82% [158/193] and "often" 16% [30/193]), and 75% [145/193] reported always adhering combined with normalized TG2-IgA. Although reporting that they were always adherent, 13 (6.7%) had not yet normalized their TG2-IgA levels completely; however, a majority of these initially had the highest TG2-IgA levels. CONCLUSIONS: GFD adherence is high in adolescents with CD detected by screening of the general population of Swedish 12-year-olds. Almost all of them had normalized serology and reported GFD adherence at the 1-year follow-up. A few adolescents who reported GFD adherence, however, had elevated TG2-IgA levels, suggesting more severe disease and/or nonadherence.

Neighborhood conditions and celiac disease risk among children in Sweden.

AIM: To investigate celiac disease (CD) clustering at different geographical levels and to examine the association between neighborhood demographic and socioeconomic conditions and the risk of neighborhood CD. METHODS: We included 2080 children diagnosed with CD between 1998 and 2003, identified from 43 of the 47 reporting hospitals in Sweden. A total of 8036 small area market statistics (SAMS) areas were included; these were nested in 253 municipalities that were further nested into eight 'nomenclature of territorial units for statistics' (NUTS) 2 regions. We performed multilevel logistic regression analyses. RESULTS: We found the highest geographical variation in CD incidence at the municipality level, compared to the region level. The probability of having CD increased in the statistical areas of (SAMS) areas with higher average annual work income, with an odds ratio (OR) of 2.24 and 95% CI of 1.76-2.85. Reduced CD risk in neighborhoods was associated with higher average age (OR 0.96; 95% CI 0.95-0.97), higher proportion of residents with a university education (OR 0.98; 95% CI 0.97-0.99), and higher level of industrial and commercial activity (OR 0.59; 95% CI 0.44-0.82). We found no significant association between CD risk and population density, proportion of Nordic to non-Nordic inhabitants, nor share of the population with only a compulsory education. CONCLUSIONS: Neighborhood composition influences cd risk this is one of the first attempts to identify factors explaining geographical variation in CD.

Noncontaminated dietary oats may hamper normalization of the intestinal immune status in childhood celiac disease.

OBJECTIVES: Life-long, strict gluten-free diet (GFD) is the only treatment for celiac disease (CD). Because there is still uncertainty regarding the safety of oats for CD patients, the aim was to investigate whether dietary oats influence the immune status of their intestinal mucosa. METHODS: Paired small intestinal biopsies, before and after >11 months on a GFD, were collected from children with CD who were enrolled in a randomized, double-blind intervention trial to either of two diets: standard GFD (GFD-std; n=13) and noncontaminated oat-containing GFD (GFD-oats; n=15). Expression levels of mRNAs for 22 different immune effector molecules and tight junction proteins were determined by quantitative reverse transcriptase (RT)-PCR. RESULTS: The number of mRNAs that remained elevated was higher in the GFD-oats group (P=0.05). In particular, mRNAs for the regulatory T cell (Treg) signature molecules interleukin-10 (IL-10) and transforming growth factor-ß1 (TGF-ß1), the cytotoxicity-activating natural killer (NK) receptors KLRC2/NKG2C and KLRC3/NKG2E, and the tight junction protein claudin-4 remained elevated. Between the two groups, most significant differences were seen for claudin-4 (P=0.003) and KLRC3/NKG2E (P=0.04). CONCLUSIONS: A substantial fraction of pediatric CD patients seem to not tolerate oats. In these patients, dietary oats influence the immune status of the intestinal mucosa with an mRNA profile suggesting presence of activated cytotoxic lymphocytes and Tregs and a stressed epithelium with affected tight junctions. Assessment of changes in levels of mRNA for claudin-4 and KLC3/NKG2E from onset to after a year on oats containing GFD shows promise to identify these CD patients.

Celiac disease risk varies between birth cohorts, generating hypotheses about causality: evidence from 36 years of population-based follow-up.

BACKGROUND: Celiac disease (CD) is a major public health problem with estimated 1-3% prevalence in the general population. In recent years an increase in CD prevalence has been reported both in Sweden and worldwide. This study aimed at examining the annual incidence rate of biopsy-proven celiac disease among children in Sweden over a 36-year period, to assess variations by age, sex and birth cohort, and to assess the clinical impact of these changes. METHODS: The National Swedish Childhood CD Register was used to identify 9107 children aged 0-14.9 years who were diagnosed with CD during the period 1973 to 2009. From 1973 to 1990 the register covered 15% of the nation, this increased to 40% during 1991-1997; a full national coverage was obtained from 1998 onwards. Estimations for the annual incidence rate, cumulative incidence and clinical impact by age groups, calendar month and birth cohorts were made. RESULTS: CD incidence is continuing to increase in the child population aged 2-14.9 years. A continued variation in CD incidence was observed in children aged 0-1.9 years, characterized by a marked decrease in most recent years. The median age at diagnosis has increased from 1.0 year in the 1970s to 6.8 years in 2009. The average number of new cases has risen from ~200 during 1973-1983 to ~600 during 2004-2009. In the birth cohorts of 2000-2002 the cumulative incidence even exceeded that of the epidemic cohorts at comparable ages. The highest cumulative incidence was observed in the birth cohorts of 1985-1995 and 2000-2002. CONCLUSIONS: CD risk varies between birth cohorts, suggesting cyclic environmental and/or lifestyle risk factors in CD etiology. More research on underlying risk factors is required in order to move forward with preventive strategies.

Usefulness of symptoms to screen for celiac disease.

OBJECTIVE: To describe the frequency of symptoms and associated conditions among screening-detected celiac disease (CD) cases and non-CD children and to evaluate questionnaire-based case-finding targeting the general population. METHODS: In a population-based CD screening of 12-year-olds, children and their parents completed questionnaires on CD-associated symptoms and conditions before knowledge of CD status. Questionnaire data for those who had their CD detected in the screening (n = 153) were compared with those of children with normal levels of CD markers (n = 7016). Hypothetical case-finding strategies were also evaluated. Questionnaires were returned by 7054 (98%) of the children and by 6294 (88%) of their parents. RESULTS: Symptoms were as common among screening-detected CD cases as among non-CD children. The frequency of children with screening-detected CD was similar when comparing the groups with and without any CD-related symptoms (2.1% vs 2.1%; P = .930) or CD-associated conditions (3.6% vs 2.1%; P = .07). Case-finding by asking for CD-associated symptoms and/or conditions would have identified 52 cases (38% of all cases) at a cost of analyzing blood samples for 2282 children (37%) in the study population. CONCLUSIONS: The current recommended guidelines for finding undiagnosed CD cases, so-called active case-finding, fail to identify the majority of previously undiagnosed cases if applied in the general population of Swedish 12-year-olds. Our results warrant further studies on the effectiveness of CD case-finding in the pediatric population, both at the clinical and population-based levels.

Prevotella jejuni sp. nov., isolated from the small intestine of a child with coeliac disease.

Five obligately anaerobic, Gram-stain-negative, saccharolytic and proteolytic, non-spore-forming bacilli (strains CD3 : 27, CD3 : 28(T), CD3 : 33, CD3 : 32 and CD3 : 34) are described. All five strains were isolated from the small intestine of a female child with coeliac disease. Cells of the five strains were short rods or coccoid cells with longer filamentous forms seen sporadically. The organisms produced acetic acid and succinic acid as major metabolic end products. Phylogenetic analysis based on comparative 16S rRNA gene sequence analysis revealed close relationships between CD3 : 27, CD3 : 28(T) and CD3 : 33, between CD3 : 32 and Prevotella histicola CCUG 55407(T), and between CD3 : 34 and Prevotella melaninogenica CCUG 4944B(T). Strains CD3 : 27, CD3 : 28(T) and CD3 : 33 were clearly different from all recognized species within the genus Prevotella and related most closely to but distinct from P. melaninogenica. Based on 16S rRNA, RNA polymerase ß-subunit (rpoB) and 60 kDa chaperonin protein subunit (cpn60) gene sequencing, and phenotypic, chemical and biochemical properties, strains CD3 : 27, CD3 : 28(T) and CD3 : 33 are considered to represent a novel species within the genus Prevotella, for which the name Prevotella jejuni sp. nov. is proposed. Strain CD3 : 28(T) ( = CCUG 60371(T) = DSM 26989(T)) is the type strain of the proposed novel species. All five strains were able to form homologous aggregates, in which tube-like structures were connecting individual bacteria cells. The five strains were able to bind to human intestinal carcinoma cell lines at 37 °C.

Transglutaminase IgA antibodies in a celiac disease mass screening and the role of HLA-DQ genotyping and endomysial antibodies in sequential testing.

OBJECTIVES: The aim of this study was to evaluate hypothetical screening strategies in a Swedish celiac disease (CD) mass screening. METHODS: Of 10,041 Swedish sixth graders born in 1993 invited to a population-based CD mass screening, 7208 participated. Anti-tissue transglutaminase (tTG) immunoglobulin (Ig) A were analyzed in all children and total serum IgA (s-IgA) in 7161 children. Additional analyses of tTG-IgG, endomysial antibodies (EMA) IgA and IgG, and human leukocyte antigen (HLA) alleles were performed according to a standardized protocol. Children with elevated levels of serological markers were recommended to undergo a small intestinal biopsy to verify diagnosis, and 153 children with CD were thus identified. Sensitivity, specificity, positive predictive values (PPVs) and negative predictive values (NPVs) were calculated and receiver operating characteristic curves were plotted. RESULTS: By lowering the cutoff for tTG-IgA, 17 additional cases of CD were identified at the cost of 32 biopsies. All children with tTG-IgA >50 U/mL (10 times the recommended upper limit of normal) had gluten enteropathy. Area under the receiver operating characteristic curve for tTG-IgA was 0.988. All cases carried HLA-DQ2 or HLA-DQ8, as did 53% of the controls. For different hypothetical screening strategies, sensitivity, specificity, PPV, and NPV ranged between 87.6% and 100%, 99.5% and 99.9%, 79.7% and 89.7%, and 99.7% and 100%, respectively. Efforts to increase sensitivity by lowering tTG-IgA cutoff would result in increased number of small intestinal biopsies and lower PPV. Sequential testing for both EMA and HLA-DQ genotyping would reduce the number of negative small intestinal biopsies. CONCLUSIONS: tTG-IgA is a robust marker when used in CD mass screening and its performance can be enhanced by sequential testing for EMA or HLA-DQ genotyping.

Prevalence of childhood celiac disease and changes in infant feeding.

OBJECTIVES: Between 1984 and 1996, Sweden experienced an "epidemic" of clinical celiac disease in children <2 years of age, attributed partly to changes in infant feeding. Whether infant feeding affects disease occurrence and/or the clinical presentation remains unknown. We investigated and compared the total prevalence of celiac disease in 2 birth cohorts of 12-year-olds and related the findings to each cohort's ascertained infant feeding. METHODS: A 2-phase cross-sectional screening study was performed in which 13 279 children from 2 birth cohorts participated: children born during the epidemic (1993) and children born after the epidemic (1997). Previously diagnosed cases were reported and confirmed. Blood samples were analyzed for serological markers and children with positive values were referred for small intestinal biopsy. Infant feeding practices in the cohorts were ascertained via questionnaires. Prevalence comparisons were expressed as prevalence ratios. RESULTS: The total prevalence of celiac disease was 29 in 1000 and 22 in 1000 for the 1993 and 1997 cohorts, respectively. Children born in 1997 had a significantly lower risk of having celiac disease compared with those born in 1993 (prevalence ratio: 0.75; 95% confidence interval: 0.60-0.93; P = .01). The cohorts differed in infant feeding (specifically, in the proportion of infants introduced to dietary gluten in small amounts during ongoing breastfeeding). CONCLUSIONS: A significantly reduced prevalence of celiac disease in 12-year-olds indicates an option for disease prevention. Our findings suggest that the present infant feeding recommendation to gradually introduce gluten-containing foods from 4 months of age, preferably during ongoing breastfeeding, is favorable.