Table 4.
Multivariate analysis of COPD according to smoking history and amount of vitamin C intake
| Smoking history | Vitamin C intake (mg) | Multivariate analysis
|
||
|---|---|---|---|---|
| OR | 95% CI | P-value | ||
| Never smoker | Lowest quartile (Q1, <48.50) | Reference | 0.802 | |
| Low-middle quartile (Q2, 48.50–84.38) | 0.906 | 0.564–1.456 | ||
| High-middle quartile (Q3, 84.38–141.63) | 0.980 | 0.559–1.717 | ||
| Highest quartile (Q4, >141.63) | 0.738 | 0.377–1.447 | ||
| Light smoker | Lowest quartile (Q1, <48.50) | Reference | 0.011* | |
| Low-middle quartile (Q2, 48.50–84.38) | 1.753 | 0.707–4.346 | ||
| High-middle quartile (Q3, 84.38–141.63) | 1.657 | 0.756–3.630 | ||
| Highest quartile (Q4, >141.63) | 0.540 | 0.226–1.290 | ||
| Medium smoker | Lowest quartile (Q1, <48.50) | Reference | 0.786 | |
| Low-middle quartile (Q2, 48.50–84.38) | 0.637 | 0.211–1.921 | ||
| High-middle quartile (Q3, 84.38–141.63) | 0.612 | 0.213–1.759 | ||
| Highest quartile (Q4, >141.63) | 0.655 | 0.253–1.694 | ||
| Heavy smoker | Lowest quartile (Q1, <48.50) | Reference | 0.019* | |
| Low-middle quartile (Q2, 48.50–84.38) | 0.586 | 0.138–2.484 | ||
| High-middle quartile (Q3, 84.38–141.63) | 0.233 | 0.094–0.576 | ||
| Highest quartile (Q4, >141.63) | 0.375 | 0.140–1.004 | ||
Note:
*
P<0.05 obtained by multivariate logistic regression analysis with adjustment of age and sex.
Abbreviations: OR, odds ratio; CI, confidence interval.