Search in the Abstract Database

Abstracts Search 2014

* = Presenting author

DOP025. High rate of IBD in younger age groups among 1 degree relatives to IBD affected cases, a population-based cohort study 1977–2011

F. Trier Moller1,2, V. Andersen3, T. Jess2, 1Southern University of Denmark, Institute for Regional Health Research, Odense, Denmark, 2Statens Serum Institut, Department of Epidemiology Research, Copenhagen, Denmark, 3Southern University of Denmark, Institute for Regional Health Research - SHS, Odense, Denmark

Background

Inflammatory bowel disease (IBD) - Ulcerative colitis (UC) and Crohn's Disease (CD) are caused by complex gene–environment interactions and the risk is increased in family members. We investigated whether the risk of IBD in relatives to IBD patients changes by age of the relatives.

Methods

Our cohort study was based on the entire Danish population during 1977–2011 (n = 8,410,048). Through a unique personal identification number assigned to each Danish citizen, sex, date and location of birth, identity of parents, and information on vital status and emigration were available. This information was used to establish kinship in the entire population. Individuals receiving a diagnosis of IBD during the time period (n = 69,915) were identified using the Danish National Registry of Patients. Risk of IBD in family members to individuals with IBD was assessed by Poisson regression analysis.

Results

The age stratified rates of IBD in 1 degree relatives to an IBD affected case, after controlling for the overall effect of age, appear from Table 1. The rate ratio of CD in individuals with two or more relatives with IBD is only 1–2 fold increased in relatives aged 60+ years, whereas it is 67-fold increased risk in relatives aged 0–10 years and 34-fold increased in relatives aged 10–19 years. The same pattern is seen in relatives who have one relative with IBD, where the risk of CD is markedly higher in younger relatives than in older relatives, and this risk pattern for CD is seen both if the IBD individual has CD (0–10 years, 12.9-fold increase) and UC (0–10 years; 6-fold increase). Likewise, the risk of UC is markedly higher in young relatives than in older relatives to persons with IBD (Table 1).

Table 1 (abstract DOP025). Rate ratio RR (95% CI) of contracting CD and UC in 1 degree family members to an IBD affected case, as compared to having a 1 degree family member without a diagnosis of IBD, stratified by age of the family member
Age of exposedRate ratio of contracting CD
Further effect of having:
Rate ratio of contracting UC
Further effect of having:
relativeOne UC relativeOne CD relative≥2 relatives with either CD or UCOne UC relativeOne CD relative≥2 relatives with either CD or UC
0 to 106.37 (4.21, 9.63)12.9 (8.00, 20.7)66.5 (21.3, 207)10.1 (7.63, 13.3)7.59 (4.55, 12.7)33.4 (8.32, 134)
10 to 194.77 (4.02,  5.66)7.92 (6.35, 9.88)34.3 (22.1, 53.3)5.34 (4.67, 6.11)3.83 (2.95, 4.98)12.5 (6.71, 23.2)
20 to 293.97 (3.45, 4.56)5.80 (4.79, 7.02)10.5 (6.61, 16.7)3.46 (3.11, 3.85)2.54 (2.07, 3.13)8.21 (5.59, 12.1)
30 to 392.63 (2.19, 3.16)3.72 (2.87, 4.83)7.95 (4.70, 13.4)3.08 (2.76, 3.43)1.99 (1.59, 2.50)6.57 (4.50, 9.58)
40 to 491.68 (1.31, 2.16)2.57 (1.84, 3.59)6.12 (3.38, 11.1)2.79 (2.46, 3.15)1.73 (1.34, 2.24)5.50 (3.68, 8.21)
50 to 591.36 (0.98, 1.89)3.77 (2.76, 5.16)2.51 (0.81, 7.78)2.32 (1.98, 2.72)1.86 (1.41, 2.45)5.29 (3.18, 8.77)
60 to 691.97 (1.44, 2.68)3.31 (2.23, 4.91)1.15 (0.16, 8.18)1.98 (1.65, 2.38)1.98 (1.46, 2.68)3.84 (2.00, 7.39)
70 to 791.42 (0.91, 2.21)1.42 (0.63, 3.16)1.75 (0.25, 12.5)2.06 (1.66, 2.54)1.49 (0.95, 2.34)1.86 (0.60, 5.76)
80+2.86 (1.57, 5.22)0.91 (0.13, 6.48)9.73 (1.37, 69.3)2.24 (1.51, 3.33)1.25 (0.47, 3.34)3.47 (0.49, 24.6)

Conclusion

We found a significant effect of age in IBD relatives on the risk of developing IBD. The rate of familial IBD is particularly high in infants and young adults, especially in multiple affected families.