The effect of dietary antioxidant on the COPD risk: the community-based KoGES (Ansan–Anseong) cohort

Figures & data

Figure 1 The flow diagram of selection of study population from Ansan and Anseong cohort.

Table 1 The general characteristics and lifestyle factors of study population

	Subjects at risk (n=6,781)	COPD (n=325)
	51.0±8.45	56.7±9.02
Age
40–44	1,966 (29.0)	52 (16.0)
45–49	1,548 (22.8)	36 (11.1)
50–54	898 (13.2)	32 (9.90)
55–59	872 (12.9)	51 (15.7)
60–64	815 (12.0)	72 (22.2)
65–69	682 (10.1)	82 (25.2)
Sex
Male	3,098 (44.0)	255 (78.5)
Female	3,683 (54.3)	70 (21.5)
BMI
<25 BMI	3,738 (55.12)	219 (67.4)
25 ≤ BMI	3,043 (44.9)	106 (32.6)
Job
Housekeeper	1,966 (29.5)	30 (9.30)
Office worker	336 (5.00)	13 (4.00)
Farmer	1,632 (24.1)	136 (42.1)
Private business	1,040 (15.4)	42 (13.0)
Sales work	96 (1.40)	0 (0.00)
Blue-collar job	390 (5.80)	13 (4.00)
Professional	295 (4.40)	16 (5.00)
Others	976 (14.4)	73 (22.6)
Education obtained
Elementary	2,049 (30.3)	122 (37.8)
Middle school	1,497 (22.2)	66 (20.4)
High school	2,185 (32.4)	95 (29.4)
More than college	1,022 (15.1)	40 (12.4)
Marriage status
In a relationship	6,138 (90.5)	287 (88.3)
Single	643 (9.50)	38 (11.7)
Type of house
Single house	3,407 (50.3)	207 (63.9)
Apartment	2,105 (31.1)	63 (19.4)
Multiplex housing	1,176 (17.4)	48 (14.8)
Others	87 (1.30)	6 (1.90)
Income (USD)
<500	1,082 (16.2)	81 (25.2)
500–990	989 (14.8)	62 (19.3)
1,000–1,490	1,047 (15.6)	54 (16.8)
1,500–1,990	970 (14.5)	40 (12.4)
2,000–2,990	1,314 (19.6)	44 (13.7)
≥3,000	1,292 (19.3)	41 (12.7)
Self-rated health
Very bad	222 (3.30)	13 (4.00)
Bad	1,936 (28.6)	90 (27.8)
Normal	2,472 (36.5)	114 (35.2)
Good	2,036 (30.1)	102 (31.5)
Very good	100 (1.50)	5 (1.50)
Physician-reported comorbidity (yes)
Asthma	103 (1.50)	11 (3.40)
Chronic respiratory	36 (0.50)	5 (1.60)
Tuberculosis	314 (4.60)	27 (8.40)
Cigarette smoker
Never	4,145 (61.6)	87 (26.9)
Formerly	1,045 (15.5)	82 (25.3)
Currently	1,540 (22.9)	155 (47.8)
Smoking pack year
<14 PYR	5,171 (76.3)	158 (48.6)
≥14 PYR	1,610 (23.7)	167 (51.4)
Alcohol drinker
Never	3,168 (46.9)	101 (31.2)
Formerly	372 (5.50)	29 (9.00)
Currently	3,219 (47.6)	194 (59.9)
Exercise
No	4,776 (70.4)	243 (74.8)
Yes	2,005 (29.6)	82 (25.3)

Abbreviations: BMI, body mass index; PYR, pack year.

Table 2 The effect of general characteristics and lifestyle factors on the risk of COPD

	cOR (95% CI)	adjOR (95% CI)a
Age, in years
40–44	Ref	Ref
45–49	0.88 (0.57–1.35)	0.79 (0.51–1.23)
50–54	1.36 (0.87–2.13)	1.25 (0.78–2.01)
55–59	2.29 (1.54–3.39)	2.38 (1.53–3.70)
60–64	3.57 (2.47–5.15)	4.01 (2.59–6.21)
65–69	5.03 (3.51–7.21)	5.08 (3.22–8.03)
		Ptrend<0.01
Sex
Male	Ref	Ref
Female	0.22 (0.17–0.28)	0.35 (0.21–0.57)
BMI
<25 BMI	Ref	Ref
25 ≤ BMI	0.58 (0.46–0.74)	0.71 (0.55–0.91)
		Ptrend =0.01
Job
Housekeeper	0.35 (0.19–0.65)	0.77 (0.36–1.62)
Office worker	Ref	Ref
Farmer	2.07 (1.20–3.57)	0.98 (0.52–1.84)
Private business	0.96 (0.52–1.75)	0.97 (0.52–1.81)
Sales work	–	–
Blue-collar job	0.78 (0.37–1.67)	1.06 (0.48–2.34)
Professional	1.30 (0.63–2.68)	1.19 (0.56–2.51)
Others	1.84 (1.04–3.25)	1.16 (0.63–2.13)
Education obtained
Elementary	Ref	Ref
Middle school	0.73 (0.54–0.99)	0.95 (0.67–1.36)
High school	0.72 (0.54–0.94)	0.95 (0.66–1.36)
More than college	0.64 (0.45–0.92)	0.71 (0.45–1.14)
		Ptrend =0.27
Marriage status
In a relationship	Ref	Ref
Single	1.28 (0.90–1.82)	1.43 (0.96–2.13)
Type of house
Single house	Ref	Ref
Apartment	0.48 (0.36–0.63)	0.77 (0.53–1.12)
Multiplex housing	0.66 (0.48–0.90)	0.93 (0.63–1.37)
Others	1.14 (0.49–2.65)	1.29 (0.53–3.18)
Income (USD)
<500	Ref	Ref
500–990	0.86 (0.62–1.21)	0.88 (0.61–1.28)
1,000–1,490	0.70 (0.50–1.00)	0.90 (0.60–1.34)
1,500–1,990	0.56 (0.38–0.82)	0.87 (0.55–1.38)
2,000–2,990	0.45 (0.31–0.65)	0.83 (0.52–1.33)
≥3,000	0.42 (0.29–0.62)	0.81 (0.49–1.34)
		Ptrend =0.10
Self-rated health
Very bad	Ref	Ref
Bad	0.78 (0.44–1.40)	0.81 (0.43–1.49)
Normal	0.77 (0.44–1.37)	0.85 (0.46–1.58)
Good	0.84 (0.47–1.49)	0.91 (0.49–1.71)
Very good	0.84 (0.29–2.39)	0.85 (0.28–2.55)
		Ptrend =0.56
Physician-reported comorbidity (yes)
Asthma	2.42 (1.28–4.58)	3.68 (1.84–7.38)
Chronic respiratory	3.24 (1.25–8.38)	1.38 (0.50–3.82)
Tuberculosis	1.95 (1.29–2.94)	1.84 (1.18–2.87)
Cigarette smoker
Never	Ref	Ref
Formerly	3.98 (2.92–5.41)	2.20 (1.45–3.35)
Currently	5.22 (3.99–6.83)	3.35 (2.28–4.92)
		Ptrend<0.01
Smoking pack year
<14 PYR	Ref	Ref
≥14 PYR	3.67 (2.93–4.60)	1.14 (0.84–1.56)
Alcohol drinker
Never	Ref	Ref
Formerly	0.51 (0.40–0.66)	1.11 (0.82–1.52)
Currently	1.32 (0.88–1.98)	1.06 (0.68–1.64)
		Ptrend =0.52
Exercise
No	Ref	Ref
Yes	0.80 (0.62–1.03)	0.94 (0.71–1.24)

Notes:

a Adjusted for age, sex, marriage status, BMI, energy, history of asthma and tuberculosis, and cigarette smoking.

Abbreviations: BMI, body mass index; PYR, pack year; cOR, crude odds ratio; adjOR, adjusted odds ratio; CI, confidence interval.

Table 3 The association between daily nutrients intake and COPD risk

	OR				Pfor trend
	Q2	Q3	Q4	Q5
Energy-source nutrients
Energy (kcal)	0.77 (0.52–1.13)	0.77 (0.52–1.13)	1.03 (0.70–1.50)	1.00 (0.68–1.47)	0.53
Protein (g)	0.85 (0.56–1.28)	0.85 (0.56–1.28)	1.01 (0.58–1.74)	0.72 (0.37–1.39)	0.54
Fat (g)	0.86 (0.58–1.29)	0.86 (0.58–1.29)	0.87 (0.54–1.38)	0.76 (0.44–1.33)	0.44
Carbohydrate (g)	0.91 (0.60–1.37)	0.91 (0.60–1.37)	0.84 (0.44–1.63)	0.76 (0.34–1.70)	0.53
Fiber (g)	0.98 (0.67–1.43)	0.98 (0.67–1.43)	1.09 (0.72–1.66)	0.92 (0.58–1.45)	0.93
Antioxidant vitamins
Vitamin A (RE)	1.16 (0.80–1.69)	1.12 (0.75–1.65)	0.92 (0.60–1.40)	1.11 (0.73–1.68)	0.95
Retinol (μg)	0.78 (0.54–1.12)	1.03 (0.71–1.49)	0.86 (0.58–1.27)	0.56 (0.36–0.87)	0.05
β-carotene (μg)	0.88 (0.61–1.29)	0.95 (0.65–1.39)	0.88 (0.60–1.31)	0.97 (0.66–1.44)	0.92
Vitamin C (mg)	0.78 (0.55–1.11)	0.79 (0.55–1.13)	0.65 (0.44–0.96)	0.66 (0.43–1.01)	0.03
Folate (μg)	0.82 (0.56–1.19)	0.82 (0.56–1.21)	1.07 (0.72–1.58)	0.71 (0.46–1.11)	0.48
Vitamin E (mg)	0.91 (0.63–1.32)	0.63 (0.41–0.96)	0.85 (0.55–1.33)	0.56 (0.34–0.94)	0.05
Other vitamins
Vitamin B1 (mg)	1.05 (0.71–1.57)	1.13 (0.72–1.75)	1.13 (0.72–1.75)	0.95 (0.52–1.74)	0.78
Vitamin B2 (mg)	0.76 (0.51–1.12)	1.01 (0.67–1.51)	1.01 (0.67–1.51)	0.58 (0.34–1.00)	0.12
Niacin (mg)	0.92 (0.62–1.36)	0.79 (0.50–1.23)	0.79 (0.50–1.23)	0.77 (0.43–1.39)	0.60
Vitamin B6 (mg)	1.02 (0.69–1.50)	0.75 (0.48–1.18)	0.75 (0.48–1.18)	0.76 (0.44–1.34)	0.84

Notes: Q1 is taken as reference; OR after adjusting for age, sex, marriage status, BMI, history of asthma and tuberculosis, energy, and cigarette smoking.

Abbreviations: OR, odds ratio; Q, quintile; RE, retinol equivalents; BMI, body mass index.

Table 4 The association between daily nutrients intake and COPD risk among men and women

	ORM				Pfor trend
	Q2	Q3	Q4	Q5
Men
Energy-source nutrients
Energy (kcal)	0.73 (0.45–1.18)	1.06 (0.68–1.65)	1.06 (0.65–1.59)	0.91 (0.58–1.43)	0.77
Protein (g)	0.87 (0.53–1.44)	0.96 (0.55–1.66)	1.01 (0.53–1.93)	0.66 (0.30–1.42)	0.45
Fat (g)	0.98 (0.60–1.61)	1.18 (0.72–1.96)	0.80 (0.45–1.40)	0.70 (0.37–1.35)	0.19
Carbohydrate (g)	1.18 (0.72–1.95)	0.94 (0.51–1.76)	1.00 (0.46–2.15)	0.80 (0.31–2.03)	0.53
Fiber (g)	1.06 (0.68–1.64)	0.89 (0.56–1.42)	0.97 (0.60–1.60)	0.80 (0.47–1.35)	0.37
Antioxidant vitamins
Vitamin A (RE)	1.31 (0.84–2.03)	1.08 (0.68–1.72)	0.88 (0.53–1.44)	0.99 (0.61–1.62)	0.40
Retinol (μg)	0.81 (0.53–1.22)	0.94 (0.61–1.46)	0.79 (0.50–1.25)	0.46 (0.28–0.78)	0.01
β-carotene (μg)	1.02 (0.66–1.58)	0.98 (0.63–1.54)	0.83 (0.52–1.33)	0.92 (0.58–1.45)	0.48
Vitamin C (mg)	0.83 (0.56–1.23)	0.68 (0.45–1.04)	0.56 (0.36–0.89)	0.61 (0.37–1.01)	0.01
Folate (μg)	0.82 (0.53–1.27)	0.83 (0.53–1.30)	0.86 (0.54–1.37)	0.58 (0.34–0.97)	0.09
Vitamin E (mg)	0.89 (0.58–1.38)	0.53 (0.32–0.87)	0.78 (0.46–1.31)	0.54 (0.31–0.98)	0.06
Women
Energy-source nutrients
Energy (kcal)	0.79 (0.41–1.54)	0.86 (0.41–1.81)	0.92 (0.43–1.99)	1.43 (0.67–3.05)	0.51
Protein (g)	0.71 (0.33–1.49)	0.99 (0.41–2.37)	0.84 (0.27–2.57)	0.90 (0.23–3.49)	0.92
Fat (g)	0.52 (0.23–1.14)	1.05 (0.50–2.23)	1.13 (0.46–2.77)	1.07 (0.36–3.20)	0.65
Carbohydrate (g)	0.42 (0.18–1.01)	0.97 (0.38–2.52)	0.67 (0.17–2.63)	1.15 (0.22–6.09)	0.99
Fiber (g)	0.72 (0.32–1.61)	1.05 (0.47–2.34)	1.47 (0.67–3.23)	1.42 (0.57–3.56)	0.21
Antioxidant vitamins
Vitamin A (RE)	0.76 (0.34–1.68)	1.22 (0.57–2.62)	1.12 (0.51–2.48)	1.56 (0.71–3.43)	0.20
Retinol (μg)	0.54 (0.22–1.29)	1.29 (0.64–2.59)	1.04 (0.50–2.18)	0.97 (0.39–2.22)	0.73
β-carotene (μg)	0.53 (0.23–1.24)	0.87 (0.40–1.88)	1.12 (0.54–2.33)	1.16 (0.55–2.47)	0.36
Vitamin C (mg)	0.52 (0.22–1.23)	1.15 (0.57–2.34)	0.90 (0.41–1.96)	0.78 (0.33–1.85)	0.92
Folate (μg)	0.78 (0.36–1.70)	0.67 (0.28–1.61)	1.93 (0.92–4.05)	1.38 (0.57–3.31)	0.14
Vitamin E (mg)	0.82 (0.40–1.67)	0.94 (0.42–2.09)	0.92 (0.39–2.20)	0.43 (0.14–1.38)	0.37

Notes: Q1 is taken as reference; OR after adjusting for age, sex, marriage status, BMI, history of asthma and tuberculosis, energy, and cigarette smoking.

Abbreviations: OR, odds ratio; Q, quintile; RE, retinol equivalents; BMI, body mass index.

Table 5 Association of FEV₁, FVC, and FEV₁/FVC with increased intake of vitamins C and E

	Value per increase 100 mg vitamin C (mL)		Value per increase 5 mg vitamin E (mL)
	Crude	Adjusted	Crude	Adjusted
FEV1	27.2 (P=0.03)	17.1 (P=0.03)	14.9 (P<0.01)	1.64 (P=0.02)
FVC	22.2 (P=0.15)	24.1 (P=0.01)	17.3 (P<0.01)	2.01 (P=0.03)
FEV1/FVC	2.50 (P=0.01)	−0.60 (P=0.51)	0.24 (P=0.01)	0.01 (P=0.88)

Note: The values are adjusted for age, sex, marriage status, BMI, history of asthma and tuberculosis, and cigarette smoking.

Abbreviations: FEV₁, forced expiratory volume; FVC, forced vital capacity; BMI, body mass index.

Table 6 Interaction between smoking and antioxidant vitamins C or E intake on COPD risk among men

	Subjects at risk		COPD cases		ORs
	Highest	Lowest	Highest	Lowest	Highest	Lowest
Vitamin C
Noncurrent smoker	1,082	475	59	47	Ref	1.42 (0.90–2.24)
Current smoker	835	445	78	71	2.54 (1.51–4.26)	2.96 (1.88–4.67)
						Pinteraction =0.43
Vitamin E
Noncurrent smoker	1,050	507	54	52	Ref	1.54 (0.94–2.52)
Current smoker	862	408	87	62	3.14 (1.87–5.25)	2.98 (1.78–4.97)
						Pinteraction =0.11

Note: OR after adjusting for age, marriage status, BMI, history of asthma and tuberculosis, and energy.

Abbreviations: OR, odds ratio; BMI, body mass index.