Table 3

Rate ratios of Crohn's disease according to age at antibiotic use and type of antibiotics used among Danish children born 1995–2003 followed from birth until 1 January 2005

Crohn's disease
Antibiotic use in last 3 monthsAntibiotic use >3 months previously
Number of casesRR95% CINumber of casesRR95% CI
No courses1111
At least 1 course144.43(1.88 to 10.44)252.27(0.88 to 5.84)
Type of antibiotics used
 Penicillin V82.92(1.22 to 6.97)221.50(0.70 to 3.23)
 Extended spectrum penicillins83.13(1.33 to 7.40)221.42(0.67 to 2.99)
 Macrolides10.97(0.13 to 7.14)111.38(0.67 to 2.87)
 Other systemics0NA51.38(0.52 to 3.62)
Age at antibiotic use*
 0–2 months0NA54.19(1.64 to 10.68)
 3 –11 months53.32(1.15 to 9.56)181.04(0.53 to 2.04)
 1 year11.53(0.15 to 15.46)221.11(0.52 to 2.35)
 2–3 years43.73(1.02 to 13.60)212.17(0.87 to 5.42)
 4+ years42.34(0.71 to 7.73)71.35(0.45 to 4.08)
  • * RRs adjusted for age, calendar period, use of other types of antibiotics and other times since use. Note that the number of cases do not sum to 14 and 25 respectively, since children can use multiple types of antibiotics at different ages.

  • RRs adjusted for age, calendar period, other ages of use and other times since use. RR for systemic antibiotics could not be estimated owing to lack of cases.