Table 1.
Distribution of the characteristics of the COPD cases and matched controls nested at first follow-up period within the Jinchang Cohort Study membership.
| Characteristics | Cases (n = 224) | Controls (n = 896) | p |
|---|---|---|---|
| Sex | |||
| Male | 145 | 580 | |
| Female | 79 | 316 | p > 0.05 |
| Age group | |||
| 21–34 | 8 | 33 | |
| 35–49 | 60 | 205 | p > 0.05 |
| 50–65 | 89 | 411 | p > 0.05 |
| 65~ | 67 | 247 | p > 0.05 |
| Race | |||
| Han Chinese | 218 | 876 | |
| Hui Chinese | 5 | 12 | p > 0.05 |
| Other ethnic groups | 1 | 8 | p > 0.05 |
| Education level | |||
| No normal education | 12 | 70 | |
| Primary school | 54 | 194 | p > 0.05 |
| Middle school | 68 | 231 | p > 0.05 |
| High school | 60 | 160 | p < 0.05 |
| College or higher | 30 | 241 | p > 0.05 |
| Working years | |||
| 0~9.99 | 15 | 52 | |
| 10~19.99 | 19 | 68 | p > 0.05 |
| 20~29.99 | 90 | 350 | p > 0.05 |
| 30~ | 100 | 426 | p > 0.05 |
| Marital status | |||
| Never married | 3 | 18 | |
| Married | 192 | 779 | p > 0.05 |
| Remarried | 3 | 16 | p > 0.05 |
| Divorced | 6 | 25 | p > 0.05 |
| Widowed | 20 | 58 | p > 0.05 |
| BMI (kg/m2) | |||
| ~25 | 137 | 576 | |
| 25~29.9 | 79 | 297 | p > 0.05 |
| 29.9~ | 8 | 23 | p > 0.05 |
| Occupational classification | |||
| Cadre | 30 | 228 | |
| Worker * | 167 | 585 | p < 0.01 |
| Technical staff | 7 | 27 | p > 0.05 |
| Office service staff | 20 | 56 | p < 0.01 |
* Workers are defined the mining/production workers (including chemical and metal products manufacturing workers and the workers involved in mining and ore dressing), the smelting workers and the refining workers.