Table 3.

Parity and baseline prevalent radiographic knee OA, including KR.

			Crude	Age, BMI, race-Adj.		Multi-Adj.*
Number of Births	Total # Knees	# (%)With ROA	RR	RR	p-value	RR	p-value
0	416	153 (36.78)	1.1 (0.9, 1.4)	1.2 (0.9, 1.5)	0.2133	1.2 (0.9, 1.5)	0.1952
1(ref)	362	119 (32.87)	1.0	1.0		1.0
2	1028	360 (35.02)	1.1 (0.9, 1.3)	1.2 (0.9, 1.4)	0.1527	1.2 (1.0, 1.4)	0.1177
3	742	335 (45.15)	1.4 (1.1, 1.7)	1.3 (1.1, 1.6)	0.0052	1.3 (1.1, 1.6)	0.0063
4	380	168 (44.21)	1.3 (1.1, 1.7)	1.2 (1.0, 1.5)	0.0725	1.2 (1.0, 1.5)	0.0770
5–12	300	154 (51.33)	1.6 (1.2, 2.0)	1.3 (1.0, 1.6)	0.0405	1.3 (1.0, 1.6)	0.0420

^*adjusted for age, BMI, race, education, occupation, injury/surgery, estrogen use, clinical site. KR was considered to be prevalent ROA.