A nationwide cohort study of inflammatory bowel disease, histological activity and fracture risk.

BACKGROUND: Individuals with inflammatory bowel disease (IBD) are at increased risk of fracture. It is unclear if this risk varies by recent histological activity. AIMS: To determine the fracture risk in IBD during periods with and without histological inflammation. METHODS: We studied a nationwide cohort of 54,591 individuals diagnosed with IBD in 1990-2016 with longitudinal data on ileo-colorectal biopsies. Fractures were identified by inpatient and hospital-based outpatient diagnoses. We derived Cox regression estimated hazard ratios (HRs) for fracture during 12 months following a histological inflammation (vs. histological remission) record after adjusting for socio-demographics, comorbidities, IBD duration, IBD-related surgery and hospitalization. We adjusted sensitivity analyses for medical IBD treatment including corticosteroids. RESULTS: Mean age of patients was 44.0 (SD = 18.3) and 45.5 (SD = 17.1) years at biopsy with histological inflammation and remission, respectively. For histological inflammation, there were 1.37 (95% CI 1.29-1.46) fractures per 100 years' follow-up versus 1.31 (95% CI 1.19-1.44) for remission (adjusted [a]HR 1.12; 95% CI 1.00-1.26; p = 0.04). HRs were similar with histological inflammation of Crohn's disease (1.11; 95% CI 0.91-1.36) and ulcerative colitis (1.18; 95% CI 1.02-1.36). Estimates were consistent across age groups. An overall small excess risk of any fracture remained after accounting for corticosteroids. A more prominently raised fracture risk was observed in corticosteroid-naïve IBD patients with histological inflammation versus histological remission (aHR 1.41; 95% CI 1.07-1.85). The aHR of hip fracture following histological inflammation was 1.29 (95% CI 0.87-1.92). CONCLUSIONS: Histological inflammation in IBD predicted a small increase in short-term fracture risk. Measures to reduce disease activity may reduce fracture risk in IBD.

Association Between Maternal Infections in Pregnancy and the Risk of Inflammatory Bowel Disease in the Offspring: Findings From Two Scandinavian Birth Cohorts.

BACKGROUND: The association of infections and antibiotic use in pregnancy and the risk of inflammatory bowel disease (IBD) development in the offspring have been scarcely investigated. We examined infection and antibiotic use in pregnancy and the risk of IBD in offspring. METHODS: We followed participants from the All Babies in Southeast Sweden (ABIS) and the Norwegian mother father and child cohort (MoBa) from birth (1997-2009) until 2020-2021. IBD diagnosis was classified as ≥2 records in national registers. Information on infections (any, gastrointestinal, and respiratory), their timing (early or late in pregnancy), and antibiotic use in pregnancy were collected from questionnaires. Cox proportional-hazard regression and meta-analytic methods were used to estimate pooled adjusted hazard ratios (aHRs) for IBD and its subtypes, adjusted for parental IBD, maternal smoking, and education. Sensitivity analyses accounted for exposure to antibiotics and infections 0-12 months of age. RESULTS: We followed 117 493 children for 2 024 299 person-years (follow-up 22.3 years in ABIS and 16.4 years in MoBa), including 451 IBD cases. The aHRs for any infection and respiratory infections in pregnancy and offspring IBD were close to one (aHR = 0.99 [95% CI = 0.73-1.33] and aHR = 1.00 [95% CI = 0.81-1.23], respectively). However, any versus no infection in early pregnancy was associated with IBD development (aHR = 1.26 [95% CI = 1.02-1.55]), particularly Crohn's disease (CD; aHR = 1.40 [95% CI = 1.01-1.93]). Any versus no gastrointestinal infection in late pregnancy was associated with offspring CD (aHR = 1.95 [95% CI = 1.34-2.84]). Antibiotic use in pregnancy was not associated with IBD in the child (aHR = 1.15 [95% CI = 0.93-1.44]). CONCLUSIONS: In this binational birth cohort study, the risk of offspring IBD varied by infection type and timing but not with maternal antibiotic use in pregnancy.

In this study, with over 117 000 participants from 2 Scandinavian birth cohorts, the type and timing of maternal infections in pregnancy were associated with the offspring's risk of inflammatory bowel disease.

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.

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.

Association Between Celiac Disease and Irritable Bowel Syndrome: A Nationwide Cohort Study.

BACKGROUND & AIMS: The aim of this study was to determine the risk of irritable bowel syndrome (IBS) diagnosis in patients with celiac disease (CD) compared with general population comparators. METHODS: Using Swedish histopathology and register-based data, we identified 27,262 patients with CD diagnosed in 2002-2017 and 132,922 age- and sex-matched general population comparators. Diagnoses of IBS were obtained from nationwide inpatient and non-primary outpatient records. Cox regression estimated hazard ratios (aHRs) for IBS adjusted for education level and Charlson Comorbidity Index. To reduce potential surveillance bias our analyses considered incident IBS diagnosis ≥1 year after CD diagnosis. Using conditional logistic regression, secondary analyses were calculated to estimate odds ratios (ORs) for IBS diagnosis ≥1 year before CD diagnosis. RESULTS: During an average of 11.1 years of follow-up, 732 celiac patients (2.7%) were diagnosed with IBS vs 1131 matched general population comparators (0.9%). Overall (≥1-year of follow-up), the aHR for IBS was 3.11 (95% confidence interval [CI], 2.83-3.42), with aHR of 2.00 (95% CI, 1.63-2.45) after ≥10 years of follow-up. Compared with siblings (n = 32,010), celiac patients (n = 19,211) had ≥2-fold risk of later IBS (aHR, 2.42; 95% CI, 2.08-2.82). Compared with celiac patients with mucosal healing, those with persistent villus atrophy on follow-up biopsy were less likely to be diagnosed with IBS (aHR, 0.66; 95% CI, 0.46-0.95). CD was also associated with having an earlier IBS diagnosis (OR, 3.62; 95% CI, 3.03-4.34). CONCLUSIONS: In patients with CD, the risk of IBS is increased long before and after diagnosis. Clinicians should be aware of these long-term associations and their implications on patient management.

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.

Histologic Remission in Inflammatory Bowel Disease and Female Fertility: A Nationwide Study.

BACKGROUND & AIMS: Inflammatory bowel disease (IBD) is linked to reduced female fertility, but it is unclear how fertility rates vary by histologic disease activity. METHODS: Nationwide IBD cohort of Swedish women aged 15 to 44 years. We examined fertility rates during periods with vs without histologic inflammation (n = 21,046; follow-up, 1990-2016) and during periods with vs without clinical activity (IBD-related hospitalization, surgery, or treatment escalation) (n = 24,995; follow-up, 2006-2020). Accounting for sociodemographics and comorbidities, we used Poisson regression to estimate adjusted fertility rate ratios (aFRRs) for live births conceived during 12-month periods of histologic inflammation (vs histologic remission) and 3-month periods of clinically active IBD (vs quiescent IBD). RESULTS: During periods with vs without histologic inflammation, there were 6.35 (95% confidence interval [CI], 5.98-6.73) and 7.09 (95% CI, 6.48-7.70) live births conceived per 100 person-years of follow-up, respectively, or 1 fewer child per 14 women with 10 years of histologic inflammation (aFRR, 0.90; 95% CI, 0.81-1.00). In women with histologic inflammation, fertility was similarly reduced in ulcerative colitis (UC) (aFRR, 0.89 [95% CI, 0.78-1.02]) and Crohn's disease (CD) (aFRR, 0.86 [95% CI, 0.72-1.04]). Clinical IBD activity was associated with an aFRR of 0.76 (95% CI, 0.72-0.79) or 1 fewer child per 6 women with 10 years of clinical activity. Fertility was reduced in clinically active UC (aFRR, 0.75 [95% CI, 0.70-0.81]) and CD (aFRR, 0.76 [95% CI, 0.70-0.82]). Finally, among women with clinically quiescent IBD, histologic inflammation (vs histologic remission) was associated with reduced fertility (aFRR, 0.85 [95% CI, 0.73-0.98]). CONCLUSIONS: An association between histologic and clinical activity and reduced female fertility in CD and UC was found. Notably, histologic inflammation was also linked to reduced fertility in women with clinically quiescent IBD.

Histologic Activity in Inflammatory Bowel Disease and Risk of Serious Infections: A Nationwide Study.

BACKGROUND & AIMS: Individuals with inflammatory bowel disease (IBD) are at increased risk of serious infections, but whether this risk varies by histologic disease activity is unclear. METHODS: This was a national population-based study of 55,626 individuals diagnosed with IBD in 1990 to 2016 with longitudinal data on ileocolorectal biopsy specimens followed up through 2016. Serious infections were defined as having an inpatient infectious disease diagnosis in the Swedish National Patient Register. We used Cox regression to estimate hazard ratios (HRs) for serious infections in the 12 months after documentation of histologic inflammation (vs histologic remission), adjusting for social and demographic factors, chronic comorbidities, prior IBD-related surgery, and hospitalization. We also adjusted for IBD-related medications in sensitivity analyses. RESULTS: With histologic inflammation vs remission, there was 4.62 (95% CI, 4.46-4.78) and 2.53 (95% CI, 2.36-2.70) serious infections per 100 person-years of follow-up, respectively (adjusted HR [aHR], 1.59; 95% CI, 1.48-1.72). Histologic inflammation (vs remission) was associated with an increased risk of serious infections in ulcerative colitis (aHR, 1.68; 95% CI, 1.51-1.87) and Crohn's disease (aHR, 1.59; 95% CI, 1.40-1.80). The aHRs of sepsis and opportunistic infections were 1.66 (95% CI, 1.28-2.15) and 1.71 (95% CI, 1.22-2.41), respectively. Overall, results were consistent across age groups, sex, and education level, and remained largely unchanged after adjustment for IBD-related medications (aHR, 1.47; 95% CI, 1.34-1.61). CONCLUSIONS: Histologic inflammation of IBD was an independent risk factor of serious infections, including sepsis, suggesting that achieving histologic remission may reduce infections in IBD. The study was approved by the Stockholm Ethics Review Board (approval numbers 2014/1287-31/4, 2018/972-32, and 2021-06209-01).

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.

Epidemiology, validation, and clinical characteristics of inflammatory bowel disease: the ABIS birth cohort study.

BACKGROUND: Birth cohort studies with linked register-based data on inflammatory bowel disease (IBD) provide opportunities to prospectively study early-life determinants of the disease. However, register-based data often lack information on clinical characteristics and rely on diagnostic algorithms. Within the All Babies in Southeast Sweden (ABIS) cohort, we examined the validity of a register-based definition of IBD, its incidence, and clinical and therapeutic characteristics at diagnosis. METHODS: We followed 16,223 children from birth (1997-1999) until the end of 2020 for the diagnosis of IBD as defined by a minimum of two diagnostic codes for IBD in the Swedish National Patient Register (NPR). We described the incidence and cumulative incidence of IBD. Through a medical record review of cases diagnosed by the end of 2017, we examined the positive predictive value (PPV) for IBD and described its clinical characteristics and treatment. RESULTS: By 2020, at an average age of 22.2 years, 113 participants (0.74%, 95% confidence interval [CI] = 0.61-0.89) had a register-based diagnosis of IBD, corresponding to an incidence of 31.3 per 100,000 person-years of follow-up; the incidence for Crohn's disease (CD) was 11.1 per 100,000 person-years and 15.8 for ulcerative colitis (UC). Of 77 participants with a register-based definition of IBD by the end of 2017, medical records were identified for 61 participants, of whom 57 had true IBD (PPV = 93%; 95%CI = 0.87-1.00). While oral 5-aminosalicylic acid treatment was equally common in newly diagnosed CD and UC patients, biologics were more often used for newly diagnosed CD. The median faecal calprotectin levels were 1206 mg/kg at diagnosis and 93 mg/kg at the last follow-up (P < 0.001). CONCLUSIONS: In this population-based sample of Swedish children and young adults the cumulative IBD incidence was 0.74. The validity of register-based definition of IBD was high and supports using such data to identify IBD patients in cohort studies.

Histological remission in inflammatory bowel disease and risk of adverse pregnancy outcomes: A nationwide study.

Background: Inflammatory bowel disease (IBD) has been linked to adverse pregnancy outcomes, but it is unclear how risks vary by histological activity. Methods: We performed a nationwide study of Swedish women diagnosed with IBD 1990-2016 and a pre-pregnancy (<12 months) colorectal biopsy with vs. without histological inflammation (1223 and 630 births, respectively). We also examined pregnancy outcomes in 2007-2016 of women with vs. without clinically active IBD (i.e., IBD-related hospitalization, surgery, or medication escalation) <12 months before pregnancy (2110 and 4993 births, respectively). Accounting for smoking, socio-demographics, and comorbidities, generalized linear models estimated adjusted risk ratios (aRRs) for preterm birth (<37 gestational weeks) and small-for-gestational age (SGA, <10th percentile weight for age). Findings: Of infants to women with vs. without histological inflammation, 9.6% (n = 117) and 6.5% (n = 41) were preterm, respectively (aRR = 1.46; 95%CI = 1.03-2.06). Histological inflammation was associated with preterm birth in ulcerative colitis (UC) (aRR = 1.64; 95%CI = 1.07-2.52), especially extensive colitis (aRR = 2.37; 95%CI = 1.12-5.02), but not in Crohn's disease (aRR = 0.99; 95%CI = 0.55-1.78). Of infants to women with vs. without histological inflammation, 116 (9.6%) and 56 (8.9%), respectively, were SGA (aRR = 1.09; 95%CI = 0.81-1.47). Clinically active disease before pregnancy was linked to preterm birth (aRR = 1.42; 95%CI = 1.20-1.69), but not to SGA birth (aRR = 1.13; 95%CI = 0.96-1.32). Finally, of infants to women without clinical activity, histological inflammation was not significantly associated with preterm birth (aRR = 1.20; 95%CI = 0.68-2.13). Interpretation: Histological and clinical activity in IBD, especially in UC, were risk factors for preterm birth. Further research is needed to determine the importance of pre-pregnancy histological activity in women without clinically-defined disease activity. Funding: The Swedish Society of Medicine.

Association of Celiac Disease and Inflammatory Bowel Disease: A Nationwide Register-Based Cohort Study.

INTRODUCTION: To determine the risk of inflammatory bowel disease (IBD) in patients with celiac disease (CeD) (and vice versa ) compared with general-population comparators. METHODS: Using Swedish histopathology and healthcare register data, we identified 48,551 patients with CeD and 83,529 with IBD diagnosed in 1969-2016. Each patient was compared with age- and sex-matched general-population comparators (CeD: n = 240,136; IBD: n = 408,195). Cox regression estimated hazard ratios (HRs) for IBD in patients with CeD and vice versa . Our main analyses were limited to events beyond the first year of follow-up to reduce potential surveillance bias. RESULTS: During follow-up, 784 (1.6%) patients with CeD were diagnosed with IBD compared with 1,015 (0.4%) matched comparators. In patients with CeD, the HR for IBD was 3.91 (95% confidence interval [CI] 3.56-4.31), with largely similar HRs for Crohn's disease (4.36; 3.72-5.11) and ulcerative colitis (3.40; 3.00-3.85). During follow-up, 644 (0.8%) patients with IBD and 597 (0.1%) comparators were diagnosed with CeD. The HR for CeD in patients with IBD was 5.49 (95% CI 4.90-6.16), with the highest risk estimates seen in ulcerative colitis (HR = 6.99; 6.07-8.05), and the HR for Crohn's disease was 3.31 (2.69-4.06). In patients with CeD and IBD, the diagnostic interval was usually <1 year; however, HRs of 3-4 were seen even after 10 years of follow-up. During 20 years of follow-up, 2.5% of patients with CeD developed incident IBD, and 1.3% of patients with IBD developed CeD. DISCUSSION: The bidirectional association between CeD diagnosis and IBD warrants attention in the initial assessment and follow-up of these conditions. Their co-occurrence, independent of temporal sequence, suggests shared etiology.

Celiac disease screening at a pediatric outpatient clinic: a feasibility study.

OBJECTIVES: Celiac disease (CD) is a common yet largely underdiagnosed disease. This study aimed to test the feasibility of incorporating a non-targeted CD screening in a pediatric outpatient setting and evaluate its short-term impact on children with serological evidence of disease. METHODS: Over five months, 500 children (aged 2-17 years) attending a general pediatric outpatient clinic in Gothenburg, Sweden, were enrolled and surveyed for current symptoms, quality of life, and background characteristics; 481 children were screened for tissue-transglutaminase antibodies (tTGA); repeated tTGA-positivity was defined as CD autoimmunity (CDA). Children with CDA were investigated for CD and for one year monitored for changes in symptoms, and quality of life. RESULTS: Eleven of 481 (2.3%) screened children had CDA. Children with CDA were younger (median 3.8 years) than those without CDA (8.8 years). No other major between-group differences were reported in background characteristics, symptoms, or quality of life. The screening was well-accepted by the families/participants. During 1-year follow-up, 8 of 11 children with CDA were diagnosed with CD. Children with screening-detected CD reported no significant changes in symptoms and quality of life and the dietary adherence rate was good. CONCLUSIONS: Non-targeted screening for CD was feasible in a general pediatric outpatient setting. While hampered by small sample size, our results are in line with previous screening studies indicating that symptoms do not differentiate CDA from non-CDA children. Also, among an overall minimal-symptomatic group of children, diagnosing CD and installation of treatment did not significantly change their well-being during 1-year follow-up.

Cancer Risk in 47,241 Individuals With Celiac Disease: A Nationwide Cohort Study.

BACKGROUND & AIMS: Celiac disease (CD) is associated with increased mortality, in part due to cancer. Most studies investigating this cancer risk involved patients diagnosed before widespread increases in CD diagnosis rates and access to gluten-free food. We performed a population-based study of the risk of cancer in CD. METHODS: We identified all patients in Sweden with CD as defined as duodenal/jejunal villus atrophy, using the Epidemiology Strengthened by histoPathology Reports in Sweden cohort. Each patient was matched to ≤5 controls by age, sex, and county. We used stratified Cox proportional hazards model, following patients from diagnosis until first cancer, or by December 31, 2016. RESULTS: Among 47,241 patients with CD, 30,080 (64%) were diagnosed since 2000. After a median follow-up of 11.5 years, the incidence of cancer was 6.5 and 5.7 per 1000 person-years in CD patients and controls, respectively. The overall risk of cancer was increased (hazard ratio [HR], 1.11; 95% confidence interval [CI], 1.07-1.15), but it was only significantly elevated in the first year after CD diagnosis (HR, 2.47; 95% CI, 2.22-2.74) and not subsequently (HR, 1.01; 95% CI, 0.97-1.05), although the risks of hematologic, lymphoproliferative, hepatobiliary, and pancreatic cancers persisted. The overall risk was highest in those diagnosed with CD after age 60 years (HR, 1.22; 95% CI, 1.16-1.29) and was not increased in those diagnosed before age 40. The cancer risk was similar among those diagnosed with CD before or after the year 2000. CONCLUSIONS: There is an increased risk of cancer in CD even in recent years, but this risk increase is confined to those diagnosed with CD after age 40 and is primarily present within the first year of diagnosis.

Work Loss in Patients With Celiac Disease: A Population-based Longitudinal Study.

BACKGROUND & AIMS: Celiac disease (CD) affects around 1% of the population worldwide. Data on work disability in patients with CD remain scarce. We estimated work loss in patients with CD, including its temporal relationship to diagnosis. METHODS: Through biopsy reports from Sweden's 28 pathology departments, we identified 16,005 working-aged patients with prevalent CD (villus atrophy) as of January 1, 2015, and 4936 incident patients diagnosed with CD in 2008 to 2015. Each patient was matched to up to 5 general-population comparators. Using nationwide social insurance registers, we retrieved prospectively recorded data on compensation for sick leave and disability leave to assess work loss in patients and comparators. RESULTS: In 2015, patients with prevalent CD had a mean of 42.5 lost work days as compared with 28.6 in comparators (mean difference, 14.7; 95% confidence interval [CI], 13.2-16.2), corresponding to a relative increase of 49%. More than one-half of the work loss (60.1%) in patients with CD was derived from a small subgroup (7%), whereas 75.4% had no work loss. Among incident patients, the annual mean difference between patients and comparators was 8.0 days (range, 5.4-10.6 days) of lost work 5 years before CD diagnosis, which grew to 13.7 days (range, 9.1-18.3 days) 5 years after diagnosis. No difference in work loss was observed between patients with or without mucosal healing at follow-up. CONCLUSIONS: Patients with CD lost more work days than comparators before their diagnosis, and this loss increased after diagnosis. Identifying patients with an increased risk of work loss may serve as a target to mitigate work disability, and thereby reduce work loss, in patients with CD.

Costs and Use of Health Care in Patients With Celiac Disease: A Population-Based Longitudinal Study.

INTRODUCTION: Celiac disease (CD) affects 1% of the population. Its effect on healthcare cost, however, is barely understood. We estimated healthcare use and cost in CD, including their temporal relationship to diagnosis. METHODS: Through biopsy reports from Sweden's 28 pathology departments, we identified 40,951 prevalent patients with CD (villous atrophy) as of January 1, 2015, and 15,086 incident patients with CD diagnosed in 2008-2015, including 2,663 who underwent a follow-up biopsy to document mucosal healing. Each patient was compared with age- and sex-matched general population comparators (n = 187,542). Using nationwide health registers, we retrieved data on all inpatient and nonprimary outpatient care, prescribed diets, and drugs. RESULTS: Compared with comparators, healthcare costs in 2015 were, on average, $1,075 (95% confidence interval, $864-1,278) higher in prevalent patients with CD aged <18 years, $715 ($632-803) in ages 18-64 years, and $1,010 ($799-1,230) in ages ≥65 years. Half of all costs were attributed to 5% of the prevalent patients. Annual healthcare costs were $391 higher 5 years before diagnosis and increased until 1 year after diagnosis; costs then declined but remained 75% higher than those of comparators 5 years postdiagnosis (annual difference = $1,044). Although hospitalizations, nonprimary outpatient visits, and medication use were all more common with CD, excess costs were largely unrelated to the prescription of gluten-free staples and follow-up visits for CD. Mucosal healing in CD did not reduce the healthcare costs. DISCUSSION: The use and costs of health care are increased in CD, not only before, but for years after diagnosis. Mucosal healing does not seem to lower the healthcare costs.

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.

Gluten Intake and Risk of Celiac Disease: Long-Term Follow-up of an At-Risk Birth Cohort.

OBJECTIVES: To determine the association between the amount of gluten intake in childhood and later celiac disease (CD), for which data are currently scarce. METHODS: The prospective Diabetes Autoimmunity Study in the Young cohort includes 1875 at-risk children with annual estimates of gluten intake (grams/d) from age 1 year. From 1993 through January 2017, 161 children, using repeated tissue transglutaminase (tTGA) screening, were identified with CD autoimmunity (CDA) and persistent tTGA positivity; of these children, 85 fulfilled CD criteria of biopsy-verified histopathology or persistently high tTGA levels. Cox regression, modeling gluten intake between ages 1 and 2 years (i.e., in 1-year-olds), and joint modeling of cumulative gluten intake throughout childhood were used to estimate hazard ratios adjusted for confounders (aHR). RESULTS: Children in the highest third of gluten intake between the ages of 1 and 2 years had a 2-fold greater hazard of CDA (aHR 2.17; 95% confidence interval [CI], 1.22-3.88; P value = 0.01) and CD (aHR 1.96; 95% CI, 0.90-4.24; P value = 0.09) than those in the lowest third. The risk of developing CDA increased by 5% per daily gram increase in gluten intake (aHR 1.05; 95% CI, 1.00-1.09; P value = 0.04) in 1-year-olds. The association between gluten intake in 1-year-olds and later CDA or CD did not differ by the child's human leukocyte antigen genotype. The incidence of CD increased with increased cumulative gluten intake throughout childhood (e.g., aHR 1.15 per SD increase in cumulative gluten intake at age 6; 95% CI, 1.00-1.32; P value = 0.04). DISCUSSION: Gluten intake in 1-year-olds is associated with the future onset of CDA and CD in children at risk for the disease.

Enterovirus as trigger of coeliac disease: nested case-control study within prospective birth cohort.

OBJECTIVE: To determine whether infection with human enterovirus or adenovirus, both common intestinal viruses, predicts development of coeliac disease. DESIGN: Case-control study nested within Norwegian birth cohort recruited between 2001 and 2007 and followed to September 2016. SETTING: Norwegian population. PARTICIPANTS: Children carrying the HLA genotype DR4-DQ8/DR3-DQ2 conferring increased risk of coeliac disease. EXPOSURES: Enterovirus and adenovirus detected using real time polymerase chain reaction in monthly stool samples from age 3 to 36 months. MAIN OUTCOME MEASURE: Coeliac disease diagnosed according to standard criteria. Coeliac disease antibodies were tested in blood samples taken at age 3, 6, 9, and 12 months and then annually. Adjusted odds ratios from mixed effects logistic regression model were used to assess the relation between viral infections before development of coeliac disease antibodies and coeliac disease. RESULTS: Among 220 children, and after a mean of 9.9 (SD 1.6) years, 25 children were diagnosed as having coeliac disease after screening and were matched to two controls each. Enterovirus was found in 370 (17%) of 2135 samples and was significantly more frequent in samples collected before development of coeliac disease antibodies in cases than in controls (adjusted odds ratio 1.49, 95% confidence interval 1.07 to 2.06; P=0.02). The association was restricted to infections after introduction of gluten. High quantity samples (>100 000 copies/µL) (adjusted odds ratio 2.11, 1.24 to 3.60; P=0.01) and long lasting infections (>2 months) (2.16, 1.16 to 4.04; P=0.02) gave higher risk estimates. Both the commonly detected enterovirus species Enterovirus A and Enterovirus B were significantly associated with coeliac disease. The association was not found for infections during or after development of coeliac disease antibodies. Adenovirus was not associated with coeliac disease. CONCLUSIONS: In this longitudinal study, a higher frequency of enterovirus, but not adenovirus, during early childhood was associated with later coeliac disease. The finding adds new information on the role of viral infections in the aetiology of coeliac disease.

Parental Smoking and Risk of Childhood-onset Type 1 Diabetes.

BACKGROUND: A few prospective studies suggest an association between maternal smoking during pregnancy and lower risk of type 1 diabetes. However, the role of unmeasured confounding and misclassification remains unclear. METHODS: We comprehensively evaluated whether maternal smoking in pregnancy predicts lower risk of childhood-onset type 1 diabetes in two Scandinavian pregnancy cohorts (185,076 children; 689 cases) and a Norwegian register-based cohort (434,627 children; 692 cases). We measured cord blood cotinine as an objective marker of nicotine exposure during late pregnancy in 154 cases and 476 controls. We also examined paternal smoking during pregnancy, in addition to environmental tobacco smoke exposure the first 6 months of life, to clarify the role of characteristics of smokers in general. RESULTS: In the pregnancy cohorts, maternal smoking beyond gestational week 12 was inversely associated with type 1 diabetes, pooled adjusted hazard ratio (aHR) 0.66 (95% CI = 0.51, 0.85). Similarly, in the Norwegian register-based cohort, children of mothers who still smoked at the end of pregnancy had lower risk of type 1 diabetes, aHR 0.65 (95% CI = 0.47, 0.89). Cord blood cotinine ≥30 nmol/L was also associated with reduced risk of type 1 diabetes, adjusted odds ratio 0.42 (95% CI = 0.17, 1.0). We observed no associations of paternal smoking during pregnancy, or environmental tobacco smoke exposure, with childhood-onset type 1 diabetes. CONCLUSION: Maternal sustained smoking during pregnancy is associated with lower risk of type 1 diabetes in children. This sheds new light on the potential intrauterine environmental origins of the disease.