From: Serum antioxidant vitamins and respiratory morbidity and mortality: a pooled analysis
 | % participants | Vitamin A (µg/dl) | Vitamin C (mg/dl) | 25-OHD (ng/mL) | Vitamin E [α-Tocopherol (mg/dl)] | ||||
---|---|---|---|---|---|---|---|---|---|
Characteristics | Median (Q1,Q3) | P | Median (Q1,Q3) | P | Median (Q1,Q3) | P | Median (Q1,Q3) | P | |
All participants | 100 | 56.6 (47.1, 67.5) | Â | 0.74 (0.36, 1.04) | Â | 24.4 (18.2, 31.2) | Â | 1.04 (0.85, 1.31) | Â |
Age groups | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 20–39 years | 46.5 | 53.5 (44.5, 63.7) | Ref. | 0.70 (0.31, 0.99) | Ref. | 25.7 (19.0, 32.8) | Ref. | 0.91 (0.78, 1.11) | Ref. |
 40–59 years | 31.8 | 57.5 (48.3, 68.8) |  < 0.001 | 0.74 (0.35, 1.03) | 0.992 | 23.7 (17.8, 30.0) | 0.003 | 1.13 (0.93, 1.40) |  < 0.001 |
 60 + years | 21.6 | 61.8 (52.1, 73.3) |  < 0.001 | 0.87 (0.51, 1.18) |  < 0.001 | 23.1 (17.4, 29.0) | 0.022 | 1.27 (1.03, 1.62) |  < 0.001 |
Sex | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Men | 47.8 | 60.5 (51.7, 70.7) |  < 0.001 | 0.67 (0.29, 0.96) |  < 0.001 | 25.8 (20.0, 32.4) |  < 0.001 | 1.04 (0.85, 1.28) |  < 0.001 |
 Women | 52.2 | 52.3 (43.3, 63.6) | 0.82 (0.44, 1.13) | 23.0 (16.7, 29.8) | 1.05 (0.86, 1.34) | ||||
Race/ethnicity | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Non-Hispanic Whites | 76.4 | 58.0 (48.6, 68.7) | Ref. | 0.77 (0.36, 1.08) | Ref. | 26.3 (20.4, 32.8) | Ref. | 1.08 (0.87, 1.36) | Ref. |
 Non-Hispanic Blacks | 10.7 | 51.2 (42.1, 62.4) |  < 0.001 | 0.57 (0.25, 0.87) |  < 0.001 | 15.6 (11.9, 20.6) |  < 0.001 | 0.91 (0.76, 1.11) |  < 0.001 |
 Mexican Americans | 5.3 | 51.7 (43.0, 61.1) |  < 0.001 | 0.70 (0.38, 0.96) |  < 0.001 | 20.8 (16.0, 26.3) |  < 0.001 | 1.00 (0.83, 1.23) |  < 0.001 |
 Other | 7.6 | 51.8 (43.3, 64.1) |  < 0.001 | 0.76 (0.47, 1.00) | 0.582 | 20.4 (15.8, 26.8) |  < 0.001 | 0.98 (0.82, 1.25) |  < 0.001 |
Income | Â | Â | Â | Â | Â | Â | Â | Â | Â |
  < $20,000 | 33.2 | 54.9 (45.5, 66.6) |  < 0.001 | 0.63 (0.25, 0.98) |  < 0.001 | 23.1 (16.8, 29.7) |  < 0.001 | 0.99 (0.81, 1.26) |  < 0.001 |
 $20,000 +  | 66.8 | 57.4 (47.9, 67.9) | 0.78 (0.43, 1.07) | 25.1 (19.0, 32.1) | 1.07 (0.87, 1.34) | ||||
Education levels | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Below high school graduate | 24.9 | 56.3 (46.9, 67.2) |  < 0.001 | 0.61 (0.23, 0.97) |  < 0.001 | 23.3 (17.4, 29.6) |  < 0.001 | 1.02 (0.83, 1.31) |  < 0.001 |
 High school graduate/Some college | 54.5 | 55.9 (46.3, 66.4) |  < 0.001 | 0.73 (0.35, 1.04) |  < 0.001 | 24.3 (17.9, 31.4) |  < 0.001 | 1.03 (0.84, 1.29) |  < 0.001 |
 College graduate or higher | 20.6 | 58.5 (49.4, 69.6) | Ref. | 0.86 (0.60, 1.11) | Ref. | 25.9 (20.3, 32.5) | Ref. | 1.10 (0.90, 1.36) | Ref. |
Cigarette smoke exposure | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 No smoke exposure | 8.5 | 57.2 (45.9, 68.0) | Ref. | 0.95 (0.71, 1.22) | Ref. | 24.1 (18.0, 30.8) | Ref. | 1.17 (0.94, 1.52) | Ref. |
 Secondhand smoke exposure | 37.3 | 55.1 (45.4, 65.6) |  < 0.001 | 0.81 (0.48, 1.07) |  < 0.001 | 24.1 (18.0, 30.4) |  < 0.001 | 1.02 (0.84, 1.28) |  < 0.001 |
 Past smokers (Quit > 5 years ago) | 18.4 | 60.9 (51.9, 72.5) |  < 0.001 | 0.85 (0.53, 1.10) |  < 0.001 | 25.4 (19.7, 31.6) |  < 0.001 | 1.18 (0.96, 1.50) | 1.000 |
 Past smokers (Quit within 5 years) | 7.1 | 58.8 (49.2, 69.6) | 0.360 | 0.75 (0.40, 1.01) |  < 0.001 | 24.4 (18.2, 32.0) | 1.000 | 1.06 (0.85, 1.30) |  < 0.001 |
 Current smokers | 28.6 | 54.9 (46.3, 65.6) | 0.057 | 0.43 (0.15, 0.84) |  < 0.001 | 24.1 (17.8, 32.0) |  < 0.001 | 0.96 (0.80, 1.19) |  < 0.001 |
BMI | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Underweight | 2.4 | 46.3 (39.9, 56.5) |  < 0.001 | 0.72 (0.30, 1.13) | 0.22 | 24.5 (17.8, 32.8) | 0.295 | 0.91 (0.79, 1.10) | 0.001 |
 Normal | 42.3 | 54.6 (45.4, 65.5) | Ref. | 0.80 (0.41, 1.11) | Ref. | 26.0 (19.6, 33.0) | Ref. | 0.99 (0.81, 1.24) | Ref. |
 Overweight | 32.9 | 59.2 (49.7, 69.7) |  < 0.001 | 0.74 (0.36, 1.02) |  < 0.001 | 24.5 (18.5, 31.0) |  < 0.001 | 1.11 (0.90, 1.41) |  < 0.001 |
 Obese | 22.4 | 56.9 (47.2, 68.0) | 0.994 | 0.63 (0.30, 0.95) |  < 0.001 | 21.4 (16.0, 27.4) |  < 0.001 | 1.08 (0.89, 1.33) |  < 0.001 |
Alcohol consumption | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Heavy drinker | 10.3 | 61.9 (51.0, 73.4) |  < 0.001 | 0.61 (0.21, 0.97) |  < 0.001 | 25.0 (18.6, 32.8) | 0.016 | 1.01 (0.84, 1.26) |  < 0.001 |
 Light/moderate drinker | 44.3 | 57.6 (48.9, 67.7) |  < 0.001 | 0.74 (0.39, 1.02) |  < 0.001 | 26.0 (19.7, 32.6) |  < 0.001 | 1.03 (0.84, 1.26) |  < 0.001 |
 Non-drinker | 45.4 | 54.0 (44.5, 65.0) | Ref. | 0.77 (0.38, 1.08) | Ref. | 23.0 (17.1, 29.5) | Ref. | 1.07 (0.86, 1.37) | Ref. |
Taking vitamin supplements | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Yes | 42.2 | 58.8 (48.7, 70.1) |  < 0.001 | 0.93 (0.63, 1.20) |  < 0.001 | 25.5 (19.5, 32.1) |  < 0.001 | 1.20 (0.96, 1.54) |  < 0.001 |
 No | 57.8 | 54.9 (45.8, 65.6) | 0.58 (0.24, 0.91) | 23.5 (17.4, 30.5) | 0.96 (0.80, 1.17) | ||||
Caloric intake tertiles | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 3rd (higher) | 33.3 | 58.8 (49.0, 68.9) |  < 0.001 | 0.69 (0.32, 0.98) |  < 0.001 | 26.2 (20.0, 32.8) |  < 0.001 | 1.02 (0.83, 1.24) |  < 0.001 |
 2nd | 34.0 | 56.5 (47.0, 67.0) | 0.279 | 0.76 (0.37, 1.07) | 0.817 | 24.8 (18.6, 31.6) |  < 0.001 | 1.04 (0.85, 1.33) |  < 0.001 |
 1st (lower) | 32.6 | 54.4 (44.8, 65.8) | Ref. | 0.78 (0.40, 1.11) | Ref. | 22.3 (16.8, 29.1) | Ref. | 1.07 (0.87, 1.38) | Ref. |
General health status | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Excellent or very good | 51.3 | 56.6 (47.4, 67.3) | Ref. | 0.80 (0.45, 1.07) | Ref. | 25.9 (19.8, 32.3) | Ref. | 1.04 (0.86, 1.30) | Ref. |
 Good | 32.9 | 56.7 (46.6, 67.3) |  < 0.001 | 0.69 (0.30, 1.03) |  < 0.001 | 23.5 (17.4, 30.7) |  < 0.001 | 1.04 (0.83, 1.31) | 0.061 |
 Fair or poor | 15.8 | 56.4 (46.7, 68.3) | 0.728 | 0.63 (0.25, 0.98) |  < 0.001 | 21.4 (16.1, 27.9) |  < 0.001 | 1.08 (0.87, 1.36) | 0.003 |
Current asthma | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Yes | 5.1 | 56.8 (48.2, 67.9) | 0.725 | 0.67 (0.33, 1.01) | 0.099 | 23.8 (17.4, 31.5) | 0.065 | 1.03 (0.87, 1.27) | 0.948 |
 No | 94.9 | 56.6 (47.0, 67.4) | 0.74 (0.36, 1.04) | 24.4 (18.2, 31.2) | 1.04 (0.85, 1.32) | ||||
Wheeze in past 12Â months | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Yes | 17.4 | 55.9 (46.7, 66.5) | 0.064 | 0.62 (0.24, 0.98) |  < 0.001 | 24.5 (18.3, 31.7) | 0.099 | 1.03 (0.85, 1.27) | 0.765 |
 No | 82.6 | 56.8 (47.1, 67.6) | 0.76 (0.39, 1.06) | 24.4 (18.1, 31.1) | 1.05 (0.85, 1.32) | ||||
Chronic bronchitis or emphysema | Â | Â | Â | Â | Â | Â | Â | Â | Â |
 Yes | 7.8 | 56.3 (46.7, 67.7) |  < 0.001 | 0.61 (0.23, 0.98) |  < 0.001 | 23.0 (17.6, 31.0) | 0.217 | 1.07 (0.88, 1.34) |  < 0.001 |
 No | 92.2 | 56.6 (47.1, 67.4) | 0.75 (0.37, 1.04) | 24.5 (18.2, 31.2) | 1.04 (0.85, 1.31) |