Table 2.

Standardized¹ incidence (per 100,000 person-years), 1996–2009, and point prevalence (per 100,000), December 31, 2009, of juvenile idiopathic arthritis, by sex and age.

	Boys				Girls				Boys and Girls
Incidence2	N	Person- yrs	Cases per 100,000	(95% CI)	N	Person- yrs	Cases per 100,000	(95% CI)	N	Person- yrs	Cases per 100,000	(95% CI)
Age group, yrs
0–5	51	781,699	5.6	(1.3–9.9)	105	743,786	12.2	(5.9–18.6)	156	1,525,484	8.8	(3.5–14.2)
6–10	51	522,150	8.5	(3.1–13.7)	92	500,196	15.9	(8.6–23.1)	143	1,022,346	12.1	(5.8–18.4)
11–15	58	543,446	9.2	(3.7–14.8)	131	520,994	21.7	(13.2–30.2)	189	1,064,441	15.4	(8.2–22.4)
Overall	160	1,847.295	7.7	(6.5–8.9)	328	1,764,976	16.4	(14.6–18.1)	488	3,612,271	11.9	(10.9–12.9)
Prevalence3	N	Population	Cases per 100,000	(95% CI)	N	Population	Cases per 100,000	(95% CI)	N	Population	Cases per 100,000	(95% CI)
Age group, yrs
0–5	7	85,578	8.6	(2.2–14.9)	31	80,969	40.1	(25.9–54.2)	38	166,547	23.8	(16.3–31.5)
6–10	31	95,340	34.0	(22.1–46.0)	51	91,643	58.3	(42.3–74.2)	82	186,983	45.9	(36.0–55.8)
11–15	46	105,366	45.7	(32.4–58.9)	87	101,373	89.7	(70.9–108.6)	133	206,739	67.3	(55.9–78.8)
Overall	84	286,284	28.6	(22.4–34.6)	169	273,985	61.6	(52.3–70.9)	253	560,269	44.7	(39.1–50.2)

¹The age and sex distribution were standardized to that of the 2000 Census for the entire US population. The Kaiser Permanente population included 102,652 boys and 98,238 girls aged 0–5, 101,000 boys and 96,888 girls aged 6–10, and 108,747 boys and 104,399 girls aged 11–15.

²The incidence rate is corrected for the sensitivity (0.95) and positive predictive value (0.82) of the validated incidence algorithm.

³The point prevalence is corrected for the sensitivity (0.87) and posiive predictive value (0.91) of the validated case-finding algorithm.