Incidence of coeliac disease over time by sex and age and relative incidence in 2008–2012 compared with 1993–1997 (N=2 063 421)
| Calendar period | |||||
|---|---|---|---|---|---|
| Calendar year | 1993–1997* | 1998–2002* | 2003–2007* | 2008–2012* | Unadjusted IRR for calendar period† (95% CI) |
| Sex | |||||
| Male | 7.8 (5.3 to 11.6) | 7.7 (6.3 to 9.3) | 9.3 (7.9 to 10.8) | 10.9 (9.6 to 12.6) | 1.39 (0.92 to 2.10) |
| Female | 8.8 (5.9 to 12.9) | 10.9 (9.2 to 13.0) | 13.5 (11.8 to 15.3) | 18.3 (16.5 to 20.3) | 2.09 (1.39 to 3.13) |
| Age (years) | |||||
| 0–2 | 16.7 (11.5 to 24.1) | 14.2 (11.1 to 18.0) | 13.9 (11.3 to 17.3) | 12.9 (10.4 to 15.8) | 0.77 (0.50 to 1.18) |
| 3–9 | 5.7 (3.4 to 9.7) | 8.7 (7.1 to 10.7) | 12.1 (10.4 to 14.0) | 16.4 (14.5 to 18.6) | 2.85 (1.66 to 4.88) |
| 10–18 | 4.1 (2.1 to 8.8) | 7.2 (5.6 to 9.2) | 9.4 (7.9 to 11.1) | 13.5 (11.8 to 15.4) | 3.24 (1.60 to 6.56) |
| Country | |||||
| England | 8.9 (6.7 to 11.9) | 9.9 (8.6 to 11.4) | 11.7 (10.5 to 13.0) | 14.8 (13.5 to 16.2) | 1.65 (1.22 to 2.24) |
| Scotland | – | 5.1 (3.0 to 8.7) | 11.2 (8.5 to 14.8) | 14.3 (11.3 to 17.9) | 2.77 (1.56 to 4.90)‡ |
| Wales | 11.0 (3.5 to 34.2) | 9.2 (5.2 to 16.2) | 10.3 (6.8 to 15.5) | 11.5 (8.1 to 16.4) | 1.04 (0.32 to 3.42) |
| Northern Ireland | 5.9 (0.8 to 42.3) | 6.3 (2.8 to 14.0) | 5.3 (2.5 to 11.2) | 16.4 (10.8 to 24.9) | 2.76 (0.37 to 20.46) |
Interaction tests: sex and calendar year, LRT p value=0.4; age group and calendar year, LRT p value<0.001; country and calendar year, LRT p value=0.05.
*Incidence rates of coeliac diseases per 100 000 person-years (95% CI).
†Comparing the latest with the earliest calendar period.
‡Since there were no incident coeliac disease cases in the Scottish practices between 1993 and 1997, we used the period 1998–2002 as baseline.
CI, confidence interval; IRR, incidence rate ratio; LRT, likelihood ratio test.