Table S4. Crude and adjusted stratified medium-term SHS exposure prevalences in COPD patients without active smoking.
| Characteristic variables | Crude rates (95% CI) | Adjusted rates (95% CI) |
|---|---|---|
| Ethnicity, % | ||
| Non-Hispanic black | 51.87 (36.01–67.47) | 53.09 (38.81–67.37) |
| Non-Hispanic white | 35.12 (28.10–42.65) | 35.18 (27.97–42.40) |
| Mexican-American and other | 19.91 (9.72–34.08) | 22.92 (13.21–32.62) |
| Family income-to-poverty ratio grading, % | ||
| High (>3.50) | 25.06 (17.69–33.68) | 22.37 (15.89–28.85) |
| Middle (>1.30–3.50) | 46.96 (35.77–58.37) | 47.29 (34.95–59.63) |
| Low (0.00–1.30) | 57.43 (43.38–70.66) | 58.51 (46.16–70.85) |
| Smoking history, % | ||
| Former | 44.07 (35.93–52.45) | 46.49 (37.62–55.37) |
| Never | 19.95 (10.81–32.15) | 18.37 (9.04–27.58) |
| Self-reported SHS at home, % | ||
| Yes | 90.33 (61.42–99.53) | 91.78 (80.56–100.00) |
| No | 32.80 (26.95–39.07) | 32.74 (26.52–38.97) |
Adjusted stratified prevalences were standardized by age groups and gender. Data obtained from the National Health and Nutrition Examination Survey (2007–2012), National Center for Health Statistics. COPD, chronic obstructive lung disease; CI, confidential interval; SHS, secondhand smoke.