The Association Between the Composite Dietary Antioxidant Index and Frailty Symptoms: Mediating Effects of Oxidative Stress

Figures & data

Table 1 Survey-Weighted Characteristics of the NHANES Sample According to CDAI Tertiles

Characteristic	CDAI Tertiles			P
	Tertile 1	Tertile 2	Tertile 3
Age (%)				<0.001
60–69	1827 (50.13)	1866 (53.93)	1947 (55.98)
70–79	1234 (32.76)	1181 (30.33)	1158 (30.72)
≥80	698 (17.11)	713 (15,74)	652 (13.30)
Sex (%)				0.01
Male	1869 (42.65)	1965 (47.44)	1870 (46.68)
Female	1890 (57.35)	1795 (52.56)	1887 (53.32)
Race (%)				<0.0001
Non-Hispanic White	1757 (74.85)	2058 (81.50)	2190 (84.18)
Non-Hispanic Black	886 (11.23)	684 (7.31)	596 (5.69)
Mexican American	547 (4.71)	497 (3.84)	444 (3.00)
Other races	569 (9.20)	521 (7.35)	527 (7.13)
Educational level (%)				<0.0001
College or above	1327 (43.34)	1738 (55.71)	2041 (63.60)
High school	935 (29.22)	956 (26.68)	857 (23.26)
Less than high school	1497 (27.45)	1066 (17.61)	859 (13.14)
Smoking status (%)				<0.0001
Current	613 (15.18)	433 (10.30)	378 (9.11)
Former	1418 (38.65)	1536 (40.64)	1540 (41.82)
Never	1728 (46.17)	1791 (49.05)	1839 (49.06)
Physical activity (%)				<0.0001
Active	1393 (41.21)	1575 (46.88)	1801 (51.75)
Inactive	2366 (58.79)	2185 (53.12)	1956 (48.25)
Poverty income ratio (%)				<0.0001
<1	848 (14.06)	552 (7.67)	449 (6.65)
1–1.99	1265 (29.38)	1173 (23.94)	1023 (19.06)
2–3.99	991 (31.34)	1148 (34.47)	1095 (29.69)
≥4	655 (25.22)	887 (33.92)	1190 (44.61)
Frailty Status (%)				<0.0001
Frail	1439 (35.74)	1253 (28.26)	1073 (24.50)
Non-frail	2320 (64.26)	2507 (71.74)	2684 (75.50)
Diabetes (%)				< 0.0001
Yes	1022 (23.68)	974 (21.68)	837 (17.86)
No	2737 (76.32)	2786 (78.32)	2920 (82.14)
Hypertension (%)				< 0.0001
Yes	2790 (72.76)	2665 (67.89)	2557 (64.16)
No	969 (27.24)	1095 (32.11)	1200 (35.84)
COPD				0.03
Yes	359 (10.54)	296 (8.29)	306 (8.38)
No	3400 (89.46)	3464 (91.71)	3451 (91.62)
Albumin (g/dl)	4.14 (0.01)	4.18 (0.01)	4.19 (0.01)	<0.0001
Uric acid (mg/dl)	5.79 (0.03)	5.69 (0.03)	5.52 (0.03)	<0.0001

Figure 1 Participants are selected according to the flowchart.

Table 2 Multiple Logistic Regression Analysis on the Association Between CDAI and the Risk of Frailty

CDAI	Weighted ORs (95% CIs)			P-Tend
	Tertiles 1 <-1.87	Tertiles 2 −1.87–0.79	Tertiles 3 >0.79
Model 1	1.00	0.71 (0.63, 0.80)***	0.58 (0.51, 0.67)***	<0.0001
Model 2	1.00	0.75 (0.66, 0.84)***	0.63 (0.56, 0.72)***	<0.0001
Model 3	1.00	0.86 (0.75, 0.97)*	0.81 (0.70, 0.93)**	0.004

Notes: *P < 0.05, **P < 0.01, ***P < 0.001. Model 1: unadjusted model. Model 2: adjusted for age, sex, race/ethnicity. Model 3: further adjusted for smoking status, educational level, family income to poverty ratio, physical activity.

Figure 2 Subgroup analysis of risk factors for the relationship between CDAI and frailty. Each stratification was adjusted for age, sex, race/ethnicity, smoking status, educational level, family income to poverty ratio and physical activity, except the stratification factor itself.

Figure 3 Restricted cubic spline plot of the association between CDAI and the risk of frailty. Model was adjusted for age, sex, race/ethnicity, smoking status, educational level, family income to poverty ratio and physical activity.

Figure 4 Estimated proportion of the association between CDAI and frailty index mediated by oxidative stress markers. (A) The association between CDAI and frailty index mediated by albumin. (B) The association between CDAI and frailty index mediated by uric acid.