Does hemochromatosis predispose to celiac disease? A study of 29,096 celiac disease patients

Investigating the role of iron status in the development of coeliac disease: a Mendelian randomisation study

OBJECTIVE

The environmental trigger behind the increasing prevalence of coeliac disease is not known. One suggested cause is iron deficiency, which is common in coeliac disease. We aimed to evaluate this possible association with Mendelian randomisation (MR), which under certain assumptions can suggest a causal relationship.

DESIGN

We conducted a two-sample MR study examining the relationship between single nucleotide polymorphisms (SNPs) associated with iron status and the presence of coeliac disease. The SNPs were drawn from a meta-analysis of three genome-wide association studies (GWAS). The association between these SNPs and coeliac disease was assessed using GWAS summary statistics from the UK Biobank. This consists of 336 638 white British individuals, 1855 with coeliac disease. We performed an MR Egger test for pleiotropy and assessed the plausibility of the assumptions of MR to evaluate for possible causality.

RESULTS

There were four SNPs strongly associated with systemic iron status. These were not associated with known risk factors for coeliac disease. All four SNPs were available in the UK Biobank coeliac disease summary statistics. Harmonising exposure and outcome associations, we found that higher iron status was negatively associated with risk of coeliac disease (OR per 1 SD increase in serum iron: 0.65, 95% CI 0.47 to 0.91). Leave-one-out analyses had consistent results, and no single SNP drove the association. All three assumptions of MR appeared plausible.

CONCLUSION

We found that genetically lower iron levels were associated with an increased risk of coeliac disease. Our findings highlight a potential opportunity for coeliac disease prevention.

Balanced by iron. Hereditary hemochromatosis and celiac disease

We present the case of a healthy 14-year-old adolescent who was referred to our hospital for an incidental alteration of the iron profile (Fe 225 ug/dl, transferrin 186 mg/dl, IST 63.93 %, ferritin 253 ng/ml). The blood count, proteinogram and renal, lipid and liver function tests were in the normal range. Abdominal ultrasound was requested with no findings of interest. The genetic analysis for hereditary hemochromatosis (HH) confirmed that the patient was homozygous for the C282Y mutation.

Immunopathogenesis and therapeutic approaches in pediatric celiac disease

Celiac Disease is an autoimmune enteropathy with increasing incidence worldwide in both adults and children. It occurs as an inflammatory condition with destruction of the normal architecture of villi on consumption of gluten and related protein products found in wheat, barley and rye. However, the exact pathogenesis is not yet fully understood. A gluten-free diet remains the main modality of therapy to date. While some patients continue to have symptoms even on a gluten-free diet, adherence to this diet is also difficult, especially for the children. Hence, there is continued interest in novel methods of therapy and the current research focus is on the promising novel non-dietary modalities of treatment. Here, we critically reviewed the existing literature regarding the pathogenesis of celiac disease in children including the role of in-utero exposure leading to neonatal and infant sensitization and its application for the development of new therapeutic approaches for these patients.

Elevated Total Iron-Binding Capacity Is Associated with an Increased Risk of Celiac Disease

BACKGROUND

Several lines of evidence suggest that abnormal iron homeostasis may itself play an important role in the development of celiac disease.

AIM

We sought to determine whether abnormalities in iron status could be detected prior to the diagnosis of celiac disease, and to understand the relationship between altered iron indices and the natural history of celiac disease.

METHODS

We conducted a case-control study at two major tertiary referral hospitals. Cases were comprised of patients with celiac disease in whom iron status was assessed prior to the diagnosis. Each case was matched to five controls without known gastrointestinal disease according to age and sex. Information on potential covariates and laboratory values within 1, 1-3, and 3-5 years prior to diagnosis was collected. We used conditional logistic regression to evaluate the effect of iron indices on risk of celiac disease.

RESULTS

We identified 157 celiac cases and 695 matched controls. Compared to participants with normal TIBC, the age-adjusted risk of celiac disease was significantly elevated among patients with elevated TIBC. For each 10 μg/dL increase in TIBC, the risk of celiac disease increased by 4.6, 3.8, and 7.9% within 1, 1-3, and 3-5 years prior to diagnosis, respectively. Patients with elevated pre-diagnosis TIBC were more likely to have abnormal liver enzymes and osteoporosis.

CONCLUSIONS

Elevated TIBC is associated with an increased risk of celiac disease. Further investigation into the potential role of altered iron homeostasis may uncover important environmental factors that contribute to the development of celiac disease.

Autoimmune Conditions in 235 Hemochromatosis Probands with HFE C282Y Homozygosity and Their First-Degree Relatives

We performed a retrospective study of autoimmune conditions (ACs) in 235 hemochromatosis probands at diagnosis by analyzing age, sex, ACs, history of first-degree family members with ACs (FH), diabetes, heavy ethanol consumption, elevated serum ALT/AST, nonalcoholic fatty liver disease, viral hepatitis, cirrhosis, iron removed to achieve iron depletion (QFe), and positivity for human leukocyte antigen (HLA) haplotypes A^∗01, B^∗08; A^∗02, B^∗44; A^∗03, B^∗07; A^∗03, B^∗14; and A^∗29, B^∗44. There were 138 men (58.7%). Median followup was 19.6 y. One or more of 19 ACs were diagnosed in each of 35 probands (14.9%). Prevalences of Hashimoto's thyroiditis, rheumatoid arthritis, and ankylosing spondylitis were 8.1% (95% CI: [5.1, 12.5]), 1.7% [0.6, 4.6], and 0.0085 [0.0015, 0.0337], respectively. Eighteen probands (7.7%) had a FH. Eight probands with ACs had 9 family members with ACs. In a logistic regression, ACs were less likely in men (odds ratio (OR) 0.3 [0.1, 0.6]) and more likely in probands with a FH (OR 4.1 [1.4, 11.8]). Overall ACs risk was not significantly associated with QFe or HLA haplotypes. Estimated survival of probands with and without ACs did not differ significantly. We conclude that ACs are common in hemochromatosis probands, especially women and probands with a FH.

Association between maternal iron supplementation during pregnancy and risk of celiac disease in children

BACKGROUND & AIMS

The aim of our study was to determine whether the use of iron supplements during pregnancy affects the risk for celiac disease in children.

METHODS

We assessed data from the prospective Norwegian Mother and Child cohort study, in which individuals with celiac disease were identified by answers on questionnaires and linkage to the Norwegian Patient Register. Complete data were available for 78,846 children (mean age 5.9 years, range 2-12 years); 314 children were identified with celiac disease. Questionnaires were given to pregnant women to collect information on use of iron-containing supplements, diet, anemia, and levels of hemoglobin.

RESULTS

Celiac disease was diagnosed in 4.65 of 1000 children whose mothers took iron supplements while they were pregnant, compared with 3.15 of 1000 children whose mothers did not. After adjusting for children's age, sex, and age of gluten introduction, and the presence of celiac disease in mothers, iron supplementation during pregnancy remained significantly associated with celiac disease in children (odds ratio [OR], 1.33; 95% confidence interval [CI], 1.05-1.68; P = .019). However, celiac disease was not associated with the mothers' intake of iron from foods (adjusted OR, 1.00; 95% CI, 0.97-1.03). Anemia before or during the early stages of pregnancy was not significantly associated with the risk of celiac disease in children (adjusted OR, 1.24; 95% CI, 0.84-2.00; P = .24). The use of iron supplements during pregnancy remained significantly associated with celiac disease in children after adjusting for children who were given iron supplements before 18 months of age, which itself was associated with celiac disease.

CONCLUSIONS

In a prospective Norwegian Mother and Child cohort study, we found an increased risk of celiac disease in children whose mothers used iron supplements during pregnancy; this association does not appear to arise from maternal anemia.

An update on laboratory diagnosis of liver inherited diseases

Liver inherited diseases are a group of genetically determined clinical entities that appear with an early chronic liver involvement. They include Wilson's disease (hepatolenticular degeneration), hereditary hemochromatosis, and alpha-1-antitrypsin deficiency. In addition, cystic fibrosis, although it is not specifically a liver disease, may cause a severe liver involvement in a significant percentage of cases. For all these pathologies, the disease gene is known, and molecular analysis may contribute to the unequivocal diagnosis. This approach could avoid the patient invasive procedures and limit complications associated with a delay in diagnosis. We review liver inherited diseases on the basis of the genetic defect, focusing on the contribution of molecular analysis in the multistep diagnostic workup.