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.

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.

Prevalence of thyroid autoimmunity in children with celiac disease compared to healthy 12-year olds.

Objectives. Studies have suggested a correlation between untreated celiac disease and risk for other autoimmune diseases. We investigated the prevalence of thyroid autoimmunity in 12-year-old children (i) with symptomatic celiac disease diagnosed and treated with a gluten-free diet, (ii) with screening-detected untreated celiac disease, and (iii) without celiac disease. Methods. Blood samples from 12632 children were collected. All celiac disease cases, previously diagnosed and newly screening-detected, were identified. Per case, 4 referents were matched. Blood samples were analyzed for autoantibodies against thyroid peroxidase (TPOAb). The cut-off value for TPO positivity was set to 100 U/mL. Results. Altogether, 335 celiac disease cases were found. In the entire celiac disease group, 7.2% (24/335) had elevated titers of TPOAb compared to 2.8% (48/1695) of the referents. Among the previously diagnosed celiac disease cases, 7.5% (7/93, OR 2.8, 95% CI 1.2-6.4) was TPOAb positive and among screening-detected cases, 7.0% (17/242, OR 2.6, 95% CI 1.5-4.6) was TPOAb positive. Conclusion. Children with celiac disease showed a higher prevalence of thyroid autoimmunity. We could not confirm the hypothesis that untreated celiac disease is associated with increased risk of developing thyroid autoimmunity. Early initiation of celiac disease treatment might not lower the risk for other autoimmune diseases.

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.