Table 1.

Crude incidence of inflammatory bowel disease among children < 10 years of age from seven Vaccine Safety Datalink sites, overall and by age group and sex – 2007–2016^*.

Sex	Age group	No. children** (col %)	Person-years	No. IBD cases (col %)	IBD incidence	No. CD cases (col %)	CD incidence	No. UC cases (col %)	UC incidence
F	0–4 years	744,135	2,030,387	37	1.8	12	0.6	20	1.0
	5–9 years	907,050	2,341,072	115	4.9	50	2.1	53	2.3
	Total female	1,183,015 (48.9)	4,371,459	152 (45.6)	3.5	62 (40.5)	1.4	73 (51.4)	1.7
M	0–4 years	781,606	2,133,470	45	2.1	14	0.7	25	1.2
	5–9 years	948,210	2,455,132	136	5.5	77	3.1	44	1.8
	Total male	1,238,138 (51.1)	4,588,602	181 (54.4)	3.9	91 (59.5)	2.0	69 (48.6)	1.5
Total	0–4 years	1,525,741	4,163,857	82	2.0	26	0.6	45	1.1
	5–9 years	1,855,260	4,796,203	251	5.2	127	2.7	97	2.0
	Total population	2,421,153 (100)	8,960,060	333 (100)	3.7	153 (100)	1.7	142 (100)	1.6

Abbreviations: IBD – inflammatory bowel disease, CD – Crohn’s disease, UC – ulcerative colitis, F – female, M – male

^*Incidence shown per 100,000 person-years; IBD columns include cases of CD, UC, and indeterminate colitis (n = 38); ages represent age at first IBD diagnosis.

^**Total female, total male, and total population columns represent numbers of unique individuals. Due to age progression from 0–4 to 5–9-year age groups, the age groups are not restricted to unique individuals and do not align with group totals.