Impact of Thyroid Autoimmunity on Thyroid Function in 12-year-old Children With Celiac Disease.

OBJECTIVES: Celiac disease (CD) is associated with thyroid autoimmunity and other autoimmune diseases. Data are, however, lacking regarding the relationship between thyroid autoimmunity and thyroid function, especially in regard to CD. Our aim was to investigate the impact of thyroid autoimmunity on thyroid function in 12-year-old children with CD compared to their healthy peers. METHODS: A case-referent study was conducted as part of a CD screening of 12-year-olds. Our study included 335 children with CD and 1695 randomly selected referents. Thyroid autoimmunity was assessed with antibodies against thyroid peroxidase (TPOAb). Thyroid function was assessed with thyroid-stimulating hormone and free thyroxine. RESULTS: TPOAb positivity significantly increased the risk of developing hypothyroidism in all children. The odds ratios (with 95% confidence intervals) were 5.3 (2.7-11) in healthy 12-year-olds, 10 (3.2-32) in screening-detected CD cases, 19 (2.6-135) in previously diagnosed CD cases, and 12 (4.4-32) in all CD cases together. Among children with TPOAb positivity, hypothyroidism was significantly more common (odds ratio 3.1; 95% CI 1.03-9.6) in children with CD (10/19) than in children without CD (12/46). CONCLUSIONS: The risk of thyroid dysfunction due to thyroid autoimmunity is larger for those with CD than their healthy peers. Our study indicates that a gluten-free diet does not reduce the risk of thyroid dysfunction. Further studies are required for improved understanding of the role of the gluten-free diet for the risk of autoimmune diseases in children with CD.

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.

Health-related quality of life is not impaired in children with undetected as well as diagnosed celiac disease: a large population based cross-sectional study.

BACKGROUND: Knowledge regarding the health-related quality of life (HRQoL) of children with celiac disease remains limited and inconclusive. We investigated the HRQoL of three groups of 12-year-olds with: i) undetected celiac disease ii) clinically diagnosed celiac disease, and iii) without celiac disease. METHODS: A school-based cross-sectional multicenter screening study invited 18 325 children, whereof 68% consented to participate. Participants provided a blood sample, which was later analyzed for anti-tissue-tranglutaminase antibodies, and alongside filled in a questionnaire. When anti-tissue-tranglutaminase antibodies were elevated, a small intestinal biopsy verified the screening-detected celiac disease diagnosis. Self-reported HRQoL was measured using Kidscreen, a generic 52 items instrument with proven reliability and validity. Scores were linearly transformed into a 0-100 scale with higher values indicating better HRQoL. Mean values with standard deviations (mean ± SD) were compared, and uni- and multivariate logistic regression models tested the odds of a low HRQoL among children with undetected or diagnosed celiac disease, respectively. RESULTS: Children with undetected celiac disease (n = 238) reported similar HRQoL as children without celiac disease (n = 12 037) (83.0 ± 11.0 vs. 82.5 ± 11.3, P = 0.51), and also similar HRQoL (82.2 ± 12.2, P = 0.28) to that of children with diagnosed celiac disease (n = 90), of whom 92% were adherent to treatment. Having undetected celiac disease did not increase the odds of low overall HRQoL, independent of sex, area of residence, study year and occurrence of gastrointestinal symptoms (adjusted odds ratio 0.77, 95% CI 0.54-1.10). Comparable results were seen for diagnosed celiac disease cases (adjusted odds ratio 1.11, 95% CI 0.67-1.85). CONCLUSION: Children with undetected celiac disease reported comparable HRQoL as their peers with diagnosed celiac disease, and those without celiac disease, when reporting prior to receiving the diagnosis through screening. Thus, children with celiac disease, both untreated and diagnosed, perceive their HRQoL as unimpaired by their disease.

Body mass index is not a reliable tool in predicting celiac disease in children.

BACKGROUND: Untreated celiac disease is traditionally believed to be associated with malabsorption and underweight. However, studies describing body mass index (BMI) in individuals at the time of diagnosis have shown contradictory results. We investigated the differences in weight, height, and BMI in 12- year-old children with screening-detected celiac disease compared to their healthy peers. METHODS: In a population-based screening study of 12,632 12-year-old children, blood samples were analyzed for markers of celiac disease. Children with elevated markers were referred for a small bowel biopsy. Weight and height were measured in 239 out of 242 children with screening-detected celiac disease (57.3% girls) and in 12,227 children without celiac disease (48.5% girls). BMI was categorized according to the International Obesity Task Force. Age- and sex-specific cut-off points for underweight, normal weight, and overweight were used. RESULTS: Children with celiac disease weighed less and were shorter than their peers (median weight 45.2 kg, interquartile range (IQR) 40.2-52.2 kg vs. 47.0 kg, IQR 41.1-54.4 kg, respectively, p = 0.01; median height 156.5 cm, IQR 151.0-162.0 cm vs. 157.5 cm, IQR 152.0-163.0 cm, respectively, p = 0.04). In comparing those with celiac disease to their healthy peers, 4.2% vs. 5.2% were underweight, 82.0% vs. 72.8% were normal weight, and 13.8% vs. 21.9% were overweight, respectively. There was no association between being underweight and the risk of having undiagnosed celiac disease (Odds ratio (OR) 1.3, 95% CI 0.7-2.4), but the risk was significantly lower among overweight children (OR 0.56, 95% CI 0.4-0.8). Median BMI was slightly lower among the children with screening-detected celiac disease compared to their healthy peers (18.6 kg/m2, IQR 17.1-19.8 kg/m2 vs. 18.8 kg/m2, IQR 17.2-21.1 kg/m2, respectively, p = 0.05), but most of the celiac disease cases had a normal BMI. CONCLUSIONS: At a population level, children with celiac disease weigh less, are shorter, and have a lower BMI compared to their peers without celiac disease, and this emphasizes the importance of early recognition and treatment of the condition. However, at an individual level, growth parameters are not reliable in establishing the diagnosis.

Mass screening for celiac disease from the perspective of newly diagnosed adolescents and their parents: a mixed-method study.

BACKGROUND: Mass screening for celiac disease (CD) as a public health intervention is controversial. Prior to implementation, acceptability to the targeted population should be addressed. We aimed at exploring adolescents' and parents' experiences of having the adolescents' CD detected through mass screening, and their attitudes towards possible future mass screening. METHODS: All adolescents (n = 145) with screening-detected CD found in a Swedish school-based screening study, and their parents, were invited to this study about one year after diagnosis. In all, 14 focus group discussions were conducted with 31 adolescents and 43 parents. Written narrative was completed by 91 adolescents (63%) and 105 parents (72%), and questionnaires returned by 114 parents (79%). Data were analyzed using qualitative content analysis. In addition, narratives and questionnaire data allowed for quantified measures. RESULTS: Adolescents and parents described how they agreed to participate "for the good of others," without considering consequences for themselves. However, since the screening also introduced a potential risk of having the disease, the invitation was regarded as "an offer hard to resist." For the majority, receiving the diagnosis was described as "a bolt of lightning," but for some it provided an explanation for previous health problems, and "suddenly everything made sense." Looking back at the screening, the predominant attitude was "feeling grateful for being made aware," but some adolescents and parents also expressed "ambivalent feelings about personal benefits." Among parents, 92% supported future CD screening. The most common opinion among both adolescents and parents was that future CD mass screening should be "a right for everyone" and should be offered as early as possible. However, some argued that it should be "only for sufferers" with symptoms, whereas others were "questioning the benefits" of CD mass screening. CONCLUSIONS: Although the incentives to participate in the CD screening were partly non-personal, and diagnosis was met with surprise, adolescents and parents felt grateful that they were made aware. They welcomed future CD screening, but suggested that it should be conducted earlier in life. Thus, CD mass screening seemed acceptable to most of those who were diagnosed and their parents.

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.