Celiac disease (CD) is an autoimmune disease affecting the small bowel mucosa linked to gluten ingestion in genetically predisposed subjects[1, 2]. The diagnosis of CD in adults is based on clinical manifestations, serology, genetics, and histology which usually shows, intraepithelial lymphocytosis (IEL), crypt hyperplasia, and villous atrophy [2, 3].
In children with positive serology, such as anti-tissue-transglutaminase antibodies (tTG) IgA > 10 times the upper limit of normal values and positive anti-endomysial antibodies (EMA), diagnosis of CD can be made without endoscopic and histological evaluation. On the other hand, children with positive tTG IgA class antibodies but lower titers (< 10 times the upper limit of normal) should undergo biopsies to decrease the risk of false positive diagnosis [2, 4].
CD is a global healthcare disease. The esteemed prevalence of CD in Western countries based on serological evaluation is 1%, whereas the biopsy-confirmed cases of CD range between 0.1 and 0.6% according to different studies and different Countries, and its incidence is continuously increasing [2, 4, 5]. It is highest in females and children, although CD incidence is increasing in adults [5–7].
Since CD mainly affects the duodenum, which is the tract that adsorbs iron from the diet, iron-deficiency anemia (IDA) represents a frequent clinical sign of CD both in children and in adults. Often the IDA is the only sign in subclinical/atypical forms of CD [8–10].
Other factors that give rise to IDA are blood loss from intestinal lesions and chronic inflammation, in which pro-inflammatory cytokines take iron outside the serum and cause decreased erythropoietin production [11, 12].
Kochhar et al. reported that 39% out of 434 CD patients had anemia as the only presenting feature [8].
In an Italian multicenter study, including 1026 patients with subclinical/silent CD, the most frequent extra-intestinal manifestation was IDA, in about 39% of cases[13].
Folate and vitamin B12 malabsorption can also be included in CD clinical manifestations. More extensive CD lesions could cause anemia (indeed folate is adsorbed in the jejunum and vitamin B12 in the terminal ileum). However, the real causes of this condition are still debated and far from being clarified [14, 15].
The main treatment for CD remains the gluten-free diet (GFD). No drug therapy is better than GFD in CD, and the current evidence does not support any adjunctive therapy [16]. In the majority of cases, strict adherence to GFD leads to the disappearance of clinical symptoms, serological signs, and histology alterations in the duodenum and the prevention of complications of CD[17].
In some patients with CD on a GFD, IDA can be persistent, these cases can be due to various conditions: nonadherence to the GFD, involuntary intake of food contaminated with gluten, a low-iron GFD, the persistence of atrophy of the intestinal mucosa or to some physiological causes of IDA, such as copious menses in fertile women, gastrointestinal occult blood loss, and urinary iron losses due to intense exercise-induced hemolysis in athletes [18–20].
Furthermore, some patients are refractory to oral iron supplementation for possible side effects (such as abdominal discomfort, constipation, diarrhea) and require periodic intravenous iron administration [21].
In patients with persistent IDA, despite normal histology of duodenal mucosa and the administration of oral iron supplementation, ultrastructural alterations of the enterocytes that can impair iron absorption should also be considered, meanwhile, intravenous iron administration is necessary in these cases [22–24]
This study aims to evaluate the prevalence of anemia in both adult and pediatric CD patients at the diagnosis and during a long period of GFD.