Table 1.

Baseline characteristics of 2,202 participants by COMT genotype, stratified by race.

Characteristic N (%) or Mean (SD)	Val/Val	Pairwise* p-value	Met/Val	Pairwise* p-value	Met/Met	Overall p-value
Unstratified (White and Black Older Adults)
	n=707		n=1,073		n=422
Black race	386 (54.6%)	<0.001	380 (35.4%)	<0.001	84 (19.9%)	<0.001
Female sex	360 (50.9%)	0.45	574 (53.5%)	0.09	205 (49.6%)	0.20
Age	73.7 (2.9)	0.34	73.5 (2.8)	0.88	73.5 (2.9)	0.36
BMI	28.0 (4.8)	0.01	27.0 (4.7)	0.30	27.2 (4.3)	<0.001
Weak quadriceps	349 (49.4%)	0.90	544 (50.7%)	0.74	210 (49.8%)	0.85
Any knee pain	228 (32.3%)	0.94	339 (31.6%)	0.74	137 (32.5%)	0.93
Six-m walk time (sec)	5.3 (1.2)	<0.001	5.2 (1.0)	0.02	5.0 (1.0)	<0.001
MPI score 7–10	148 (20.9%)	0.0002	135 (12.6%)	0.74	56 (13.3%)	<0.001
White Older Adults
	n=321		n=693		n=338
Female sex	138 (43.0%)	0.37	352 (50.8%)	0.19	157 (46.5%)	0.06
Age	73.88 (2.80)	0.24	73.56 (2.79)	0.75	73.62 (2.91)	0.24
BMI	26.62 (4.22)	0.88	26.35 (4.27)	0.23	26.66 (3.70)	0.44
Weak quadriceps	179 (55.8%)	0.38	380 (54.8%)	0.46	177 (52.4%)	0.65
Any knee pain	84 (26.2%)	0.37	213 (30.7%)	0.64	99 (29.3%)	0.33
Six-m walk time (sec)	4.89 (0.84)	0.96	4.97 (0.91)	0.21	4.89 (3.70)	0.29
MPI score 7–10	30 (9.3%)	0.90	48 (6.9%)	0.14	30 (8.9%)	0.13
Black Older Adults
	n=386		n=380		n=84
Female sex	164 (42.5%)	0.95	158 (41.6%)	0.83	36 (42.9%)	0.96
Age	73.48 (2.92)	0.16	73.31 (2.83)	0.35	72.99 (2.78)	0.32
BMI	29.07 (4.93)	0.56	28.06 (5.28)	0.03	29.46 (5.82)	0.01
Weak quad strength	170 (44.0%)	0.43	164 (43.2%)	0.52	33 (39.3%)	0.73
Any knee pain	144 (37.3%)	0.18	126 (33.2%)	0.04	38 (45.2%)	0.10
Six-m walk time (sec)	5.71 (1.24)	0.63	5.57 (1.02)	0.57	5.64 (1.05)	0.23
MPI score 7–10	27 (7.0%)	Ref	31 (8.2%)	Ref	11 (13.1%)	Ref

^*Pairwise p-values calculated with the Met/Met group serving as the reference group.