Table 3.
Association Between Quintiles of the Cumulative Average of Fiber Intake and Newly Diagnosed Chronic Obstructive Pulmonary Disease in Women and Men Among Former Smokers (n = 51,652) and Current Smokers (n = 32,353), Nurses’ Health Study (1984–2000) and Health Professionals Follow-up Study (1986–1998)
| Quintile of Intake |
Ptrend | |||||
| Quintile 1 | Quintile 2 | Quintile 3 | Quintile 4 | Quintile 5 | ||
| Former smokers | ||||||
| Total fiber | ||||||
| Median, g/day | 11.3 | 15.1 | 18.3 | 22.0 | 28.4 | |
| No. of cases | 49 | 45 | 48 | 40 | 44 | |
| No. of person-years | 57,235 | 61,659 | 62,775 | 62,015 | 60,314 | |
| Multivariate RR (95% CI)a | 1.00 | 0.74 (0.48, 1.13) | 0.74 (0.48, 1.15) | 0.56 (0.35, 0.91) | 0.60 (0.36, 0.99) | 0.03 |
| Multivariate RR (95% CI)b | 1.00 | 0.76 (0.50, 1.16) | 0.78 (0.50, 1.21) | 0.61 (0.37, 1.00) | 0.68 (0.40, 1.16) | 0.11 |
| Cereal fiber | ||||||
| Median, g/day | 2.2 | 3.5 | 4.7 | 6.2 | 9.0 | |
| No. of cases | 50 | 53 | 37 | 42 | 44 | |
| No. of person-years | 58,278 | 60,803 | 62,282 | 61,553 | 61,082 | |
| Multivariate RR (95% CI)a | 1.00 | 1.03 (0.69, 1.54) | 0.68 (0.44, 1.07) | 0.76 (0.48, 1.18) | 0.73 (0.46, 1.14) | 0.07 |
| Multivariate RR (95% CI)b | 1.00 | 1.04 (0.69, 1.54) | 0.71 (0.46, 1.12) | 0.81 (0.52, 1.28) | 0.80 (0.51, 1.29) | 0.20 |
| Fruit fiber | ||||||
| Median, g/day | 1.4 | 2.6 | 3.7 | 5.1 | 7.6 | |
| No. of cases | 47 | 47 | 44 | 51 | 37 | |
| No. of person-years | 56,217 | 61,520 | 62,604 | 62,612 | 61,045 | |
| Multivariate RR (95% CI)a | 1.00 | 0.95 (0.63, 1.43) | 0.84 (0.55, 1.28) | 0.94 (0.62, 1.43) | 0.64 (0.40, 1.01) | 0.09 |
| Multivariate RR (95% CI)b | 1.00 | 0.98 (0.65, 1.48) | 0.91 (0.59, 1.39) | 1.05 (0.68, 1.61) | 0.75 (0.46, 1.23) | 0.41 |
| Vegetable fiber | ||||||
| Median, g/day | 3.5 | 5.0 | 6.2 | 7.8 | 10.6 | |
| No. of cases | 49 | 42 | 49 | 38 | 48 | |
| No. of person-years | 56,095 | 61,292 | 62,338 | 62,683 | 61,590 | |
| Multivariate RR (95% CI)a | 1.00 | 0.76 (0.50, 1.15) | 0.87 (0.58, 1.31) | 0.65 (0.42, 1.01) | 0.82 (0.53, 1.28) | 0.31 |
| Multivariate RR (95% CI)b | 1.00 | 0.78 (0.51, 1.19) | 0.92 (0.59, 1.40) | 0.72 (0.45, 1.14) | 0.95 (0.59, 1.54) | 0.77 |
| Current smokers | ||||||
| Total fiber | ||||||
| Median, g/day | 10.8 | 14.9 | 18.1 | 22.0 | 28.7 | |
| No. of cases | 168 | 123 | 86 | 90 | 41 | |
| No. of person-years | 39,819 | 30,031 | 25,014 | 20,443 | 16,942 | |
| Multivariate RR (95% CI)a | 1.00 | 0.84 (0.66, 1.08) | 0.70 (0.52, 0.93) | 0.91 (0.67, 1.23) | 0.56 (0.38, 0.85) | 0.03 |
| Multivariate RR (95% CI)b | 1.00 | 0.85 (0.66, 1.08) | 0.70 (0.54, 0.97) | 0.96 (0.69, 1.29) | 0.60 (0.40, 0.94) | 0.09 |
| Cereal fiber | ||||||
| Median, g/day | 2.1 | 3.4 | 4.6 | 6.1 | 9.0 | |
| No. of cases | 162 | 126 | 94 | 84 | 42 | |
| No. of person-years | 40,488 | 30,423 | 24,541 | 20,469 | 16,328 | |
| Multivariate RR (95% CI)a | 1.00 | 1.02 (0.80, 1.30) | 0.94 (0.72, 1.24) | 0.98 (0.73, 1.30) | 0.63 (0.44, 0.91) | 0.05 |
| Multivariate RR (95% CI)b | 1.00 | 1.02 (0.79, 1.30) | 0.95 (0.73, 1.26) | 0.99 (0.76, 1.36) | 0.66 (0.46, 0.94) | 0.09 |
| Fruit fiber | ||||||
| Median, g/day | 1.2 | 2.5 | 3.7 | 5.0 | 7.6 | |
| No. of cases | 200 | 114 | 90 | 68 | 36 | |
| No. of person-years | 44,676 | 29,369 | 23,304 | 19,006 | 15,894 | |
| Multivariate RR (95% CI)a | 1.00 | 0.88 (0.69, 1.11) | 0.93 (0.72, 1.21) | 0.94 (0.70, 1.25) | 0.65 (0.45, 0.95) | 0.09 |
| Multivariate RR (95% CI)b | 1.00 | 0.90 (0.71, 1.14) | 0.98 (0.75, 1.27) | 1.00 (0.74, 1.35) | 0.72 (0.49, 1.06) | 0.33 |
| Vegetable fiber | ||||||
| Median, g/day | 3.4 | 4.9 | 6.2 | 7.7 | 10.8 | |
| No. of cases | 133 | 97 | 107 | 101 | 70 | |
| No. of person-years | 32,290 | 28,263 | 25,770 | 23,385 | 22,541 | |
| Multivariate RR (95% CI)a | 1.00 | 0.80 (0.61, 1.04) | 0.93 (0.72, 1.21) | 1.02 (0.78, 1.34) | 0.82 (0.60, 1.13) | 0.74 |
| Multivariate RR (95% CI)b | 1.00 | 0.81 (0.62, 1.06) | 0.97 (0.75, 1.27) | 1.09 (0.82, 1.45) | 0.92 (0.66, 1.28) | 0.68 |
Abbreviations: CI, confidence interval; RR, relative risk.
Adjusted for age, sex, pack-years, pack-years2, energy intake, US region, physician visits, body mass index, and physical activity.
Adjusted for age, sex, pack-years, pack-years2, energy intake, US region, physician visits, body mass index, physical activity, omega-3 polyunsaturated fatty acid intake (from foods and supplements), cured meat intake, and other sources of fiber (total fiber intake not adjusted for the specific fiber types).