Table 3.
Associations between SES and COPD among participants in this study.
| Overall (n = 2421) | Men (n = 1188) | Women (n = 1233) | Gender interaction | ||||||||
| Items | COPD prevalence, n (%) | OR (95% CI) | COPD prevalence, n (%) | OR (95% CI) | COPD prevalence, n (%) | OR (95% CI) | OR (95% CI) | ||||
| Model 1∗ | Model 2† | Model 1∗ | Model 2† | Model 1∗ | Model 2† | Model 1∗ | Model 2† | ||||
| Educational attainment (years)‡ | |||||||||||
| ≤9 | 245/1928 (12.7) | 1 | 1 | 176/893 (19.7) | 1 | 1 | 69/1033 (6.7) | 1 | 1 | 1 | 1 |
| 10–12 | 35/405 (8.6) | 0.65 (0.45, 0.94) | 0.72 (0.48, 1.07) | 32/239 (13.4) | 0.63 (0.42, 0.95) | 0.81 (0.53, 1.24) | 3/168 (1.8) | 0.26 (0.08, 0.82) | 0.37 (0.11, 1.21) | 0.61 (0.78, 0.79) | 0.78 (0.59, 1.03) |
| ≥13 | 5/88 (5.7) | 0.41 (0.17, 1.03) | 0.41 (0.16, 1.07) | 3/56 (5.4) | 0.23 (0.07, 0.75) | 0.27 (0.08, 0.90) | 2/32 (6.3) | 0.93 (0.22, 3.98) | 1.94 (0.43, 8.79) | 0.58 (0.34, 0.99) | 0.73 (0.39, 1.37) |
| Occupation§ | |||||||||||
| Blue collar | 206/1673 (12.3) | 1 | 1 | 149/777 (19.2) | 1 | 1 | 57/893 (6.4) | 1 | 1 | 1 | 1 |
| White collar | 79/748 (10.6) | 0.84 (0.64, 1.11) | 0.60 (0.43, 0.83) | 62/411 (15.1) | 0.75 (0.54, 1.04) | 0.62 (0.43, 0.90) | 17/340 (5.0) | 0.78 (0.45, 1.36) | 0.60 (0.31, 1.16) | 0.57 (0.49, 0.66) | 0.73 (0.62, 0.87) |
| FAI (tertiles) | |||||||||||
| Lower | 135/823 (16.4) | 1 | 1 | 101/385 (26.2) | 1 | 1 | 34/437 (7.8) | 1 | 1 | 1 | 1 |
| Middle | 87/856 (10.2) | 0.58 (0.43, 0.77) | 0.78 (0.57, 1.07) | 60/422 (14.2) | 0.47 (0.33, 0.67) | 0.62 (0.42, 0.89) | 27/435 (6.2) | 0.79 (0.47, 1.33) | 1.39 (0.78, 2.47) | 0.61 (0.51, 0.74) | 0.91 (0.73, 1.13) |
| Upper | 63/742 (8.5) | 0.47 (0.34, 0.65) | 0.68 (0.49, 0.97) | 50/381 (13.1) | 0.43 (0.29, 0.62) | 0.63 (0.42, 0.93) | 13/361 (3.6) | 0.44 (0.23, 0.86) | 0.82 (0.41, 1.64) | 0.51 (0.41, 0.63) | 0.76 (0.59, 0.98) |
Model 1 was a univariable analysis with SES indicators as main effects and study sites as random effects.
Model 2 was a multivariable analysis after adjustment for age, gender, residence, outdoor and indoor air pollution, body weight status and cigarette smoking, in addition to Model 1.
Educational attainment referred to schooling years completed.
Blue collars included farmers, factory workers, forestry workers, fishers, salespersons, houseworkers, and vehicle drivers; white collars included office workers, teachers, doctors, academic researchers, and government officials. CI: Confidence interval; COPD: Chronic obstructive pulmonary disease; FAI: Family average income; OR: Odds ratio; SES: Socioeconomic status.