Table 2. Association between lifestyle and respiratory factors and COPD among adults aged ≥50 in 10 CKB study areas, China, 2020–2021.
| Factors | Males (n=6,707) | Females (n=11,852) | P for sexual difference |
| Note: Values in the table were ORs (95% CIs). For lifestyle factors, models were adjusted for age, study areas, household income, education leve in the table. For respiratory factors, models were further adjusted the respiratory factors in the table. Physical activity was divided by tertiles. Central obesity was defined as waist circumference ≥90 cm for males and ≥85 cm for females. Respiratory symptoms included coughing frequently, coughing up sputum after getting up in the morning, and wheezing or having a whistle in the chest. History of respiratory diseases before 18 years old included pneumonia, bronchitis, or tuberculosis. Family history of respiratory diseases included COPD, chronic bronchitis, emphysema, and cor pulmonale. Abbreviation: COPD=chronic obstructive pulmonary disease; CKB=China Kadoorie Biobank; MET h/d=metabolic equivalent of task hours per day; BMI=body mass index; OR=odds ratio; CI=confidence interval. | |||
| Lifestyle factors | |||
| Smoking status | 0.152 | ||
| Never | 1.00 | 1.00 | |
| Former | 1.48 (1.11, 1.97) | 3.10 (1.48, 6.48) | |
| Current and 1–14 cigarettes/d | 1.97 (1.57, 2.47) | 2.17 (1.42, 3.31) | |
| Current and ≥15 cigarettes/d | 2.14 (1.73, 2.64) | 2.72 (1.14, 6.50) | |
| Alcohol drinking | 0.288 | ||
| Non-current weekly | 1.00 | 1.00 | |
| Former weekly | 1.06 (0.83, 1.35) | 0.81 (0.47, 1.39) | |
| Current weekly | 0.93 (0.67, 1.29) | 0.42 (0.14, 1.20) | |
| Current daily | 0.87 (0.72, 1.06) | 1.11 (0.65, 1.90) | |
| Daily intake of fresh fruit | 0.236 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.03 (0.86, 1.23) | 1.08 (0.89, 1.31) | |
| Daily intake of red meat | 0.726 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.15 (0.94, 1.42) | 0.81 (0.64, 1.02) | |
| Physical activity (MET h/d) | 0.514 | ||
| Tertile 1 | 1.00 | 1.00 | |
| Tertile 2 | 0.89 (0.73, 1.08) | 0.88 (0.70, 1.09) | |
| Tertile 3 | 0.86 (0.71, 1.04) | 0.97 (0.79, 1.19) | |
| BMI (kg/m2) | 0.916 | ||
| <18.5 | 1.44 (0.98, 2.12) | 1.47 (0.97, 2.22) | |
| 18.5–23.9 | 1.00 | 1.00 | |
| 24.0–27.9 | 0.52 (0.42, 0.65) | 0.57 (0.45, 0.71) | |
| ≥28.0 | 0.42 (0.30, 0.59) | 0.49 (0.35, 0.68) | |
| Central obesity | 0.621 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.21 (0.97, 1.52) | 1.18 (0.94, 1.47) | |
| Passive smoking | 0.617 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.02 (0.86, 1.22) | 1.08 (0.88, 1.33) | |
| Household air pollution | 0.591 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.06 (0.76, 1.48) | 1.32 (0.84, 2.08) | |
| Respiratory factors | |||
| Respiratory symptoms | 0.185 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.65 (1.40, 1.95) | 1.28 (1.05, 1.56) | |
| History of respiratory diseases before 18 years old | 0.571 | ||
| No/don't know | 1.00 | 1.00 | |
| Yes | 2.22 (1.40, 3.53) | 2.65 (1.69, 4.16) | |
| Chronic cough until 14 years old | 0.505 | ||
| Rarely/don’t know | 1.00 | 1.00 | |
| Sometimes | 1.32 (0.87, 2.00) | 1.89 (1.30, 2.75) | |
| >8 weeks/year | 1.96 (1.30, 2.97) | 2.28 (1.59, 3.28) | |
| Family history of respiratory diseases | 0.086 | ||
| No | 1.00 | 1.00 | |
| Yes | 1.80 (1.46, 2.21) | 1.42 (1.14, 1.77) | |