Association between composite dietary antioxidant index and stroke among individuals with diabetes

Table 1 Characteristics of subjects with or without stroke

Characteristics	Total, n = 6735	Non-stroke, n = 6124	Stroke, n = 611	P value
Age in years	59.5 ± 13.6	58.8 ± 13.6	67.4 ± 10.7	< 0.001
Sex				0.156
Male	51.5	51.8	48.7
Female	48.5	48.2	51.3
Race				< 0.001
Non-Hispanic White	60.7	60.3	65.0
Non-Hispanic Black	15.4	15.2	17.2
Mexican American	9.8	10.1	6.4
Other Hispanic	5.7	6.0	2.5
Other race	8.4	8.4	8.8
Education				< 0.001
Lower than high school	10.6	10.4	13.2
High school	39.4	38.6	48.1
Higher than high school	50.0	51.0	38.6
Marital status				0.053
Married/living with partner	62.5	63.3	54.7
Widowed/divorced/separated	27.9	26.8	40.1
Never married	9.6	10.0	5.2
Poverty income ratio				< 0.001
≤ 1.30	26.2	25.5	33.1
1.3 to ≤ 3.5	39.7	39.1	47.3
> 3.5	34.1	35.4	19.6
Smoking status				0.007
Nonsmoker	48.6	49.2	42.7
Former smoker	34.7	34.4	37.1
Current smoker	16.7	16.4	20.2
Alcohol use				0.002
No	33.3	32.7	40.1
Yes	66.7	67.3	59.9
Energy intake, kcal	1940.82 ± 900.52	1967.09 ± 909.80	1655.64 ± 734.62	< 0.001
BMI in kg/m2				0.429
< 25.0	11.77	11.77	11.86
25 to < 30	25.68	25.88	23.36
≥ 30	62.55	62.35	64.78
Hypertension				< 0.001
No	34.3	36.0	16.4
Yes	65.7	64.1	83.6
Hypercholesterolemia				0.002
No	38.6	39.1	32.5
Yes	61.4	60.9	67.5
CDAI	0.28 ± 3.97	0.38 ± 4.01	-0.77 ± 3.29	< 0.001

Data are presented as mean (SD) or n (%). BMI: Body mass index; CDAI: Composite dietary antioxidant index.

Table 2 Comparison of each component of the composite dietary antioxidant index among the non-stroke group and stroke group

Variables	Total, n = 6735	Non-stroke, n = 6124	Stroke, n = 611	P value
Vitamin A in mcg	449 (252-736)	453 (255-743)	400 (220-676)	0.026
Vitamin C in mg	50.6 (21.4-105.2)	51.3 (22.0-105.4)	44.2 (18.0-101.3)	0.093
Vitamin E in mg	5.99 (3.77-9.23)	6.10 (3.81-9.38)	5.13 (3.28-7.46)	< 0.001
Zinc in mg	8.99 (6.10-13.06)	9.09 (6.20-13.18)	7.81 (5.04-11.66)	< 0.001
Selenium in mcg	94.3 (65.1-131.2)	95.9 (66.3-133.4)	79.1 (55.8-111.5)	< 0.001
Carotenoid in mcg	4740.0 (1675.0-10809.0)	4851.0 (1759.2-10902.8)	3655.0 (1124.0-9827.0)	0.001

Data are presented as the median (interquartile range).

Table 3 Association of composite dietary antioxidant index and stroke

Factor	Model 1		Model 2		Model 3
	OR (95%CI)	P value	OR (95%CI)	P value	OR (95%CI)	P value
CDAI (continuous)	0.91 (0.89-0.94)	< 0.001	0.93 (0.90-0.96)	< 0.001	0.96 (0.92-0.99)	0.019
CDAI-Q1	Ref.	-	Ref.	-	Ref.	-
CDAI-Q2	0.70 (0.55-0.88)	0.003	0.70 (0.55-0.89)	0.004	0.74 (0.57-0.96)	0.024
CDAI-Q3	0.59 (0.46-0.75)	< 0.001	0.60 (0.46-0.77)	< 0.001	0.68 (0.51-0.90)	0.007
CDAI-Q4	0.56 (0.43-0.72)	< 0.001	0.62 (0.48-0.80)	< 0.001	0.72 (0.53- 0.98)	0.037
CDAI-Q5	0.38 (0.29-0.51)	< 0.001	0.46 (0.34-0.61)	< 0.001	0.57 (0.40-0.83)	0.003
P for trend	< 0.0001		< 0.0001		0.007

Model 1 was unadjusted; Model 2 was adjusted for age, sex, race, education, marital status and poverty income ratio; Model 3 was further adjusted for drinker, smoker, body mass index, energy intake, hypertension and hypercholesterolemia. Subjects with a composite dietary antioxidant index in the lowest quintile group served as the reference group. CDAI: Composite dietary antioxidant index; CI: Confidence interval; OR: Odds ratio; Q: Quintile; Ref.: Reference.

Table 4 Stratified analyses of the associations between the composite dietary antioxidant index and stroke

Characteristics	Quintile 1	Quintile 2	Quintile 3	Quintile 4	Quintile 5	P for interaction
Sex						0.135
Male	Ref.	0.88 (0.62-1.24)	0.58 (0.39-0.88)	0.63 (0.40-0.99)	0.58 (0.34-0.98)
Female	Ref.	0.60 (0.40-0.88)	0.77 (0.52-1.14)	0.82 (0.53-1.26)	0.56 (0.33-0.95)
Age in years						0.088
≤ 60	Ref.	0.44 (0.25-0.78)	0.46 (0.25-0.85)	0.74 (0.41-1.34)	0.41 (0.19-0.88)
> 60	Ref.	0.88 (0.65-1.17)	0.80 (0.58-1.11)	0.74 (0.52-1.07)	0.68 (0.45-1.03)
BMI						0.300
< 30	Ref.	0.65 (0.45-0.95)	0.48 (0.31-0.74)	0.57 (0.36-0.91)	0.45 (0.26-0.79)
≥ 30	Ref.	0.81 (0.58-1.14)	0.85 (0.60-1.21)	0.86 (0.58-1.26)	0.67 (0.42-1.07)
Race						0.424
White	Ref.	0.75 (0.50-1.13)	0.86 (0.55-1.33)	0.94 (0.58-1.51)	0.74 (0.42-1.31)
Others	Ref.	0.73 (0.52-1.02)	0.56 (0.38-0.81)	0.59 (0.39-0.88)	0.48 (0.29-0.78)
Smoker						0.611
Yes	Ref.	0.68 (0.49-0.95)	0.54 (0.37-0.79)	0.67 (0.45-1.00)	0.48 (0.29-0.78)
No	Ref.	0.77 (0.51-1.16)	0.83 (0.54-1.27)	0.74 (0.46-1.19)	0.67 (0.39-1.17)
Drinker						0.225
Yes	Ref.	0.61 (0.42-0.88)	0.44 (0.29-0.68)	0.52 (0.33-0.81)	0.40 (0.24-0.68)
No	Ref.	0.94 (0.59-1.48)	0.89 (0.54-1.47)	1.04 (0.61-1.78)	0.84 (0.44-1.59)
Hypertension						0.843
Yes	Ref.	0.75 (0.57-1.00)	0.66 (0.48-0.90)	0.71 (0.51-1.00)	0.55 (0.36-0.82)
No	Ref.	0.69 (0.36-1.30)	0.87 (0.44-1.71)	0.84 (0.40-1.75)	0.79 (0.32-1.91)
Hypercholesterolemia						0.375
Yes	Ref.	0.68 (0.49-0.95)	0.66 (0.46-0.95)	0.57 (0.38-0.85)	0.47 (0.29-0.76)
No	Ref.	0.87 (0.56-1.34)	0.61 (0.37-1.00)	1.01 (0.61-1.70)	0.72 (0.38-1.34)

The odds ratio and 95% confidence interval were obtained from multivariable logistic regression models after adjusting for age, sex, race, education, marital status, poverty income ratio, drinker, smoker, body mass index, energy intake, hypertension and hypercholesterolemia. BMI: Body mass index; Ref.: Reference.