Table 2.

Estimated Prevalence and Incidence of Diagnosed Symptomatic Knee OA by Age, Sex, and Obesity Status

Obesity status	Sex	Age	Estimated prevalence (%)(using NHIS 2007–08 data) (95% CI)	Estimated incidence (annual, %) (95% CI)
Non-obese	Male	25–34	0.74 (0.61, 0.89)	0.12 (0.12, 0.12)
		35–44	1.74 (1.51, 2.00)	0.13 (0.12, 0.13)
		45–54	3.61 (3.21, 4.06)	0.22 (0.22, 0.22)
		55–64	6.70 (6.09, 7.37)	0.37 (0.37, 0.38)
		65–74	9.83 (9.01, 10.71)	0.20 (0.19, 0.20)
		75–84	11.64 (10.51, 12.88)	0.13 (0.12, 0.13)
		85+	12.94 (10.86, 15.34)	0.04 (0.04, 0.04)
	Female	25–34	0.88 (0.73, 1.05)	0.14 (0.14, 0.14)
		35–44	2.06 (1.83, 2.31)	0.15 (0.14, 0.15)
		45–54	4.26 (3.90, 4.64)	0.27 (0.27, 0.27)
		55–64	7.85 (7.22, 8.52)	0.43 (0.43, 0.43)
		65–74	11.44 (10.48, 12.47)	0.27 (0.27, 0.27)
		75–84	13.50 (12.44, 14.65)	0.16 (0.16, 0.16)
		85+	14.97 (13.04, 17.12)	0.06 (0.06, 0.06)
Obese	Male	25–34	1.54 (1.26, 1.87)	0.25 (0.24, 0.25)
		35–44	3.58 (3.12, 4.11)	0.24 (0.24, 0.24)
		45–54	7.25 (6.49, 8.09)	0.44 (0.43, 0.44)
		55–64	13.00 (11.76, 14.33)	0.64 (0.64, 0.65)
		65–74	18.48 (16.71, 20.39)	0.32 (0.32, 0.33)
		75–84	21.48 (19.33, 23.78)	0.17 (0.17, 0.18)
		85+	23.54 (20.24, 27.19)	0.05 (0.05, 0.05)
	Female	25–34	2.41 (2.02, 2.88)	0.37 (0.37, 0.38)
		35–44	5.53 (4.93, 6.21)	0.40 (0.39, 0.40)
		45–54	10.93 (10.01, 11.92)	0.57 (0.57, 0.58)
		55–64	18.94 (17.52, 20.44)	1.02 (1.01, 1.02)
		65–74	26.20 (24.25, 28.23)	0.41 (0.40, 0.41)
		75–84	29.94 (27.73, 32.23)	0.28 (0.27, 0.28)
		85+	32.45 (28.79, 36.31)	0.10 (0.10, 0.10)