Table 2.
Prevalence of COPD among participants by socio-demographic attributes and risk factors in this study.
| COPD prevalence (n = 2421) | ||||
| Items | n | % (95% CI) | χ2 values | P values |
| Overall | 285 | 11.8 (10.5, 13.1) | ||
| Age (years) | 139.81 | <0.001 | ||
| 40–49 | 20 | 3.1 (1.8, 4.4) | ||
| 50–59 | 71 | 8.6 (6.7, 10.6) | ||
| 60–69 | 126 | 17.7 (14.9, 20.6) | ||
| ≥70 | 68 | 27.9 (22.2, 33.5) | ||
| Residence | 1.47 | 0.225 | ||
| Urban | 151 | 12.6 (10.7, 14.4) | ||
| Rural | 134 | 11.0 (9.2, 12.7) | ||
| Gender | 80.56 | <0.001 | ||
| Men | 211 | 17.8 (15.6, 19.9) | ||
| Women | 74 | 6.0 (4.7, 7.3) | ||
| Educational attainment (years) | 8.59 | 0.014 | ||
| ≤9 | 245 | 12.7 (11.2, 14.2) | ||
| 10–12 | 35 | 8.6 (5.9, 11.4) | ||
| ≥13 | 5 | 5.7 (0.8, 10.5) | ||
| Occupation∗ | 1.53 | 0.217 | ||
| Blue collar | 206 | 12.3 (10.7, 13.9) | ||
| White collar | 79 | 10.6 (8.4, 12.8) | ||
| FAI (tertile) | 26.82 | <0.001 | ||
| Lower | 135 | 16.4 (13.9, 18.9) | ||
| Middle | 87 | 10.2 (8.1, 12.2) | ||
| Upper | 63 | 8.5 (6.5, 10.5) | ||
| BMI (kg/m2)† | 7.74 | 0.021 | ||
| <24 | 130 | 11.3 (11.7, 16.1) | ||
| 24–27 | 117 | 11.0 (9.1, 12.9) | ||
| ≥28 | 38 | 9.0 (6.3, 11.8) | ||
| Smoking status‡ | 111.05 | <0.001 | ||
| Smokers | 200 | 20.0 (17.5, 22.4) | ||
| Non-smokers | 85 | 6.0 (4.8, 7.2) | ||
| Outdoor air pollution (PM2.5) | 5.07 | 0.023 | ||
| <75 μg/m3 | 169 | 10.7 (9.2, 12.2) | ||
| ≥75 μg/m3 | 116 | 13.8 (11.5, 16.1) | ||
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.
Body weight status was assessed based on BMI cutoffs specifically recommended for Chinese adults.
Smokers referred to either current (continuously smoked at least one cigarette every day for at least 1 year or totally smoked over 18 packs in a year) or former (met the criteria of current smokers previously but had not smoked for >1 year) smokers, while non-smokers were those not meeting the current/former smokers’ criteria. BMI: Body mass index; CI: Confidence interval; COPD: Chronic obstructive pulmonary disease; FAI: Family average income; PM2.5: Particulate matter (PM) with a diameter less than 2.5 μm.