Increasing prevalence of coeliac disease over time

BACKGROUND

The number of coeliac disease diagnoses has increased in the recent past and according to screening studies, the total prevalence of the disorder is around 1%.

AIM

To establish whether the increased number of coeliac disease cases reflects a true rise in disease frequency.

METHODS

The total prevalence of coeliac disease was determined in two population-based samples representing the Finnish adult population in 1978-80 and 2000-01 and comprising 8000 and 8028 individuals, respectively. Both clinically-diagnosed coeliac disease patients and previously unrecognized cases identified by serum endomysial antibodies were taken into account.

RESULTS

Only two (clinical prevalence of 0.03%) patients had been diagnosed on clinical grounds in 1978-80, in contrast to 32 (0.52%) in 2000-01. The prevalence of earlier unrecognized cases increased statistically significantly from 1.03% to 1.47% during the same period. This yields a total prevalence of coeliac disease of 1.05% in 1978-80 and 1.99% in 2000-01.

CONCLUSIONS

The total prevalence of coeliac disease seems to have doubled in Finland during the last two decades, and the increase cannot be attributed to the better detection rate. The environmental factors responsible for the increasing prevalence of the disorder are issues for further studies.

Anti-human versus anti-guinea pig tissue transglutaminase antibodies as the first-level serological screening test for coeliac disease in the general population

BACKGROUND

So far the reliability of the anti-guinea pig and anti-human tissue transglutaminase antibodies for the coeliac disease diagnosis has been evaluated in selected groups of patients.

AIM

To compare the diagnostic accuracy of anti-human versus anti-guinea pig tissue transglutaminase in the coeliac disease screening of the general population.

SUBJECTS

Two healthy Italian populations living in Marche region and in Western Sardinia.

METHODS

Both anti-guinea pig and anti-human tissue transglutaminase were determined using an enzyme-linked immunosorbent assay-based commercially available kit (Eu-tTG, Eurospital, Trieste, Italy).

RESULTS

During the period 1999-2001, 3541 subjects (1500 from "continental" Italy and 2041 from Sardinia) were screened for coeliac disease using both anti-guinea pig and anti-human tissue transglutaminase as first-level tests. Both these tests were negative in 3439/3541 sera, while 29 resulted positive for both of them and 73 showed discordant results. Overall, 50 intestinal biopsies were performed in 22, 21 and 7 subjects with positivity to both screening tests, to anti-guinea pig and to anti-human tissue transglutaminase alone, respectively. A coeliac disease diagnosis was made in 25 subjects giving an overall prevalence of 1:126 individuals. The anti-tissue transglutaminase specificity and sensitivity were 98 and 92% for guinea pig and 99.6 and 96% for human tissue transglutaminase, respectively.

CONCLUSIONS

The anti-human tissue transglutaminase test should definitely replace the anti-guinea pig-derived one as first-level screening tool for identifying all subjects who need the second-level investigations (small intestinal biopsy).

Prevalence of celiac disease among blood donors in Brazil

OBJECTIVE

There are no studies on the prevalence of celiac disease (CD) in either Brazil or, as far as we know, South America. The aim of this study was to determine the prevalence of CD in healthy blood donors in the city of Brasilia, Brazil.

METHODS

Sera were obtained, independently of age and gender, from an unselected group of 2045 blood donors attending the Hematological Center of Brasilia. An IgG antigliadin antibody (AGA) test was used as a first-level screening step, followed by IgA-AGA test, serum IgA antiendomysium (EMA), and total serum IgA determination performed in all sera showing abnormally high IgG-AGA results. Jejunal biopsy was suggested for all subjects showing at least one of the following: IgA-EMA positivity; IgG-AGA and IgA-AGA positivity; IgG-AGA positivity and selective IgA deficiency. AGA was determined by an enzyme-linked immunosorbent assay (ELISA) technique and IgA-EMA was ascertained by indirect immunofluorescence on cryostat sections of monkey esophagus. Jejunal mucosa samples were obtained with a Watson capsule.

RESULTS

Sixty-two (3.03%) blood donors had IgG-AGA above the cut-off values. Fifty-eight individuals showed isolated high values of IgG-AGA, whereas four had simultaneously increased IgG and IgA-AGA. Three patients had positive IgA-EMA test (one with both IgG- and IgA-AGA and two with only IgG-AGA) and underwent jejunal biopsies that disclosed complete villous atrophy associated with an increased number of intraepithelial lymphocytes and hypertrophic criptae. In this study group, the prevalence of biopsy-proven celiac disease was 1.47 +/- 1.66 in 1000 subjects.

CONCLUSIONS

We found a prevalence of undiagnosed CD of 1:681 among apparently healthy blood donors. These preliminary results support the view that CD is not a rare disease in Brazil.

Quantitative antigliadin antibody measurement in clinical practice: an Italian multicentre study. SIGEP Working Group on Quantitative AGA Standardization

BACKGROUND

The determination of class G and A serum antigliadin antibodies remains one of the most widely used screening tests for coeliac disease. The results from different laboratories are not always comparable, on account of changes in the technique and the different ways of expressing the results.

AIMS

To: a) evaluate the physiological variation of serum antigliadin antibodies expressed in ng/ml, and b) establish the cut-off of quantitative antigliadin antibodies.

PATIENTS

Patients were 127 individuals with active coeliac disease. Controls were 395 non-coeliac subjects (198 females and 197 males) aged 6 months to 45 years (median age: 4.9 years).

METHODS

Antigliadin antibody enriched samples were obtained by affinity chromatography. The concentration of the eluted antigliadin antibodies was evaluated by nephelometry and enzyme-linked immunosorbent assay to establish a primary standard. An enzyme-linked immunosorbent assay for antigliadin antibody determination was run according to standard procedures.

RESULTS

In controls, IgG-antigliadin antibody showed high variability in the 50th-90th centile range that peaked during the second year of life while IgA-antigliadin antibodies showed a lower variability and a less pronounced trend to decreasing values with age. A certain degree of overlapping between controls and coeliac patients was seen for both IgA- and IgG-antigliadin antibodies. The receiver operating characteristic analysis showed that the best discrimination was achieved by a cut-off of 8-10 ng/ml for IgA-antigliadin antibodies and 150-200 ng/ml for IgG-antigliadin antibodies.

CONCLUSIONS

Antigliadin antibody concentration is not normally distributed and changes with age in non-coeliac subjects. The receiver operating characteristic analysis is a valuable tool for fixing the antigliadin antibody cut-offs between control and diseased individuals. The diagnosis of coeliac disease should always be confirmed by intestinal biopsy.