Table 2. Annual incidence of pediatric intussusception in South Korea.

Year	New cases of intussusception			Incidence (per 105 person-years)						M/F incidence ratio
	Boys	Girls	Total	Boys	Girls	Total	IRR	IRR 95% CI	p-value
2007	2,140	1,156	3,296	37.4	22.4	30.2	Reference			1.67
2008	1,887	1,036	2,923	33.5	20.3	27.2	0.90	0.86–0.95	<0.0001	1.65
2009	1,714	987	2,701	31.1	19.7	25.7	0.85	0.81–0.89	<0.0001	1.58
2010	2,212	1,189	3,401	41.2	24.3	33.1	1.10	1.04–1.15	0.0002	1.70
2011	1,668	912	2,580	31.9	19.0	25.7	0.85	0.81–0.90	<0.0001	1.67
2012	1,785	979	2,764	35.0	20.9	28.2	0.93	0.89–0.98	0.0076	1.68
2013	1,891	1,110	3,001	38.1	24.2	31.4	1.04	0.99–1.09	0.1265	1.58
2014	1,567	931	2,498	32.5	20.8	26.9	0.89	0.84–0.94	<0.0001	1.56
2015	1,586	879	2,465	33.8	20.1	27.2	0.90	0.85–0.95	<0.0001	1.68
2016	1,747	1,015	2,762	38.2	23.8	31.3	1.03	0.98–1.09	0.2011	1.61
2017	1,333	720	2,053	30.0	17.3	23.9	0.79	0.75–0.83	<0.0001	1.73
Total	19,530	10,914	30,444	34.8	21.2	28.3				1.64

The annual incidence of pediatric intussusception was calculated by dividing annual new cases by each mid-year population aged <18 years.

M: male, F: female, IRR: incidence rate ratio, CI: confidence interval.

IRR, 95% CI, and p-values were calculated using Poisson regression.