A novel serogenetic approach determines the community prevalence of celiac disease and informs improved diagnostic pathways

Table 1 Serology, HLA-DQ status, and inferred prevalence of CD

	Total	HLA-DQ 2.5/8/2.2-positive, observed,(expected) n	HLA-DQ 2.5/8/2.2-positive, RR (95% CI)	Excess HLA-DQ 2.5/8/2.2-positive, n	Prevalence per 1.000 (95% CI)
Biopsy-confirmed CD
F + M	356	351	1.78 (1.71 to 1.84)^a		NA
Biopsy-confirmed CD; four of five HLA-DQ2.5-DQ8-DQ2.2- re-investigated
F + M	352	351	1.80 (1.73 to 1.89)^a		NA
Community random sample of age-stratified cohorts of adults
F	1,065	596	1		0
M	921	513	1		0
Community sample: initially positive for TG2 IgA
F	48	34 (27)	1.28 (1.06 to 1.55)^b	14	13.4 (2.4 to 26.8)
M	68	44 (38)	1.18 (0.98 to 1.42)^NS	12	13.2 (−2.9 to 32.8)
Community sample: initially positive for TG2 IgA, and confirmed positive for EMA
F	13	13 (7)	1.80 (1.71 to 1.90)^c	11	10.8 (9.5 to 12.1)
M	13	13 (7)	1.82 (1.71 to 1.93)^c	12	12.5 (10.9 to 14.2)
Community sample: initially positive for composite TG2/DGP IgA/IgG
F	55	41 (31)	1.36 (1.15 to 1.60)^d	20	19.2 (7.5 to 32.9)
M	73	46 (41)	1.14 (0.95 to 1.38) ^NS	11	11.6 (−5.4 to 32.0)
Community sample: initially positive for composite TG2/DGP IgA/IgG, and confirmed positive for TG2 IgA, DGP-G-+, or DGP-A
F	37	30 (21)	1.47 (1.23 to 1.74)^e	19	17.5 (8.9 to 27.6)
M	44	29 (25)	1.19 (0.96 to 1.49) ^NS	9	9.8 (−2.7 to 25.3)
Community sample: – initially positive for TG2/DGP IgA/IgG, and confirmed positive for TG2 IgA, DGP-G, and DGP-A
F	10	10 (6)	1.80 (1.71 to 1.90)^d	9	8.3 (7.3 to 9.3)
M	11	11 (6)	1.82 (1.72 to 1.93)^e	10	10.6 (9.3 to 12.1)

Abbreviations: CD, celiac disease; DGP, Deamidated gliadin-derived peptide; EMA, endomysial immunofluorescence IgA; F, female; HLA, human leukocyte antigen; Ig, immunoglobulin; M, male; NA, not applicable; NS, not significant; RR, relative risk; TG2, transglutaminase-2.
Compared with community M + F: ^a P<0.0001 (χ² two-tailed); ^b P<0.04, ^c P<0.001, ^d P<0.005, ^e P<0.002, (Fisher’s exact test, two-tailed).

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