Coeliac disease in subjects with secondary hyperparathyroidism

Coeliac disease (CD) may present in its classical form with diarrhoea and weight loss, but also with atypical symptoms that are both related and unrelated to malabsorption. Osteomalacia or osteopenia following malabsorption of calcium and vitamin D is known to occur in patients with CD, and in such cases secondary hyperparathyroidism (SHP) caused by low serum calcium levels is frequently found. However, the prevalence of CD in subjects with SHP has not been reported.

In the Tromsø study 2001, serum parathyroid hormone (PTH) and calcium were measured in 7954 subjects of whom 6061 were eligible for follow-up. From this group, 97 subjects with SHP (serum PTH> or =6.5 pmol/l and serum calcium <2.40 mmol/l) and 104 matched control subjects were re-examined with serological tests for CD (anti-tissue transglutaminase, anti-gluten IgA and IgG).

CD was diagnosed in 4 subjects, all from the original SHP group. At the re-examination, only 29 of the 97 subjects with SHP still had elevated serum PTH levels. Among these were 3 of the subjects with CD. When grouping the serological test results as negative, borderline or positive, there was a significant difference between the SHP group and the controls for anti-tissue transglutaminase and anti-gluten IgA (p<0.05).

Subjects with SHP, at least when SHP is persistent, should be tested for CD.