Sensitivity analysis of the association between chronic obstructive pulmonary disease (COPD) severity grades and underweight and obesity using different reference values in a multinomial regression analysis with normal weight as the reference
| Subjects | Underweight | Obesity | |
| OLIN reference values using LLN for COPD and restrictive spirometry | |||
| Non-COPD | 1462 | 1 | 1 |
| COPD grade 1 | 56 | 1.23 (0.35–4.25) | 0.58 (0.26–1.26) |
| COPD grade 2 | 114 | 1.69 (0.78–3.66) | 0.53 (0.30–0.94) |
| COPD grades 3 and 4 | 35 | 3.38 (1.16–9.82) | 0.52 (0.20–1.36) |
| Berglund reference values, fixed ratio | |||
| Non-COPD | 2342 | 1 | 1 |
| COPD grade 1 | 75 | 1.35 (0.67–2.71) | 0.41 (0.26–0.66) |
| COPD grade 2 | 183 | 1.49 (0.71–3.14) | 0.92 (0.60–1.40) |
| COPD grades 3 and 4 | 52 | 3.66 (1.24–10.84) | 0.52 (0.22–1.25) |
| ECSC reference values, fixed ratio | |||
| Non-COPD | 1590 | 1 | 1 |
| COPD grade 1 | 199 | 1.14 (0.58–2.25) | 0.40 (0.26–0.63) |
| COPD grade 2 | 157 | 1.46 (0.70–3.0) | 0.86 (0.56–1.30) |
| COPD grades 3 and 4 | 37 | 3.47 (1.20–10.06) | 0.48 (0.20–1.17) |
| GLI reference values using LLN | |||
| Non-COPD | 2614 | 1 | 1 |
| COPD grade 1 | 63 | 0.91 (0.27–3.10) | 0.34 (0.19–0.61) |
| COPD grade 2 | 142 | 1.30 (0.55–3.06) | 0.87 (0.61–1.26) |
| COPD grades 3 and 4 | 42 | 2.85 (0.90–9.03) | 0.54 (0.28–1.05) |
| Analyses on random sample with fixed ratio and GLI reference values | |||
| Non-COPD | 573 | 1 | 1 |
| COPD grade 1 | 75 | 1.77 (0.65–4.87) | 0.46 (0.22–0.98) |
| COPD grade 2 | 53 | 1.42 (0.41–4.95) | 0.70 (0.31–1.58) |
| COPD grades 3 and 4 | 9 | 2.91 (0.31–27.76) | 0.80 (0.13–4.80) |
Data are presented as odds ratios (95% CI) unless otherwise stated. All analyses were adjusted for sex, age, smoking habits, socioeconomic status, coronary artery disease, heart failure, hypertension and diabetes with the same model as in table 4. OLIN: Obstructive Lung Disease in Northern Sweden; LLN: lower limit of normal; ECSC: European Community for Steel and Coal; GLI: Global Lung Initiative.