Table 1.
Baseline characteristics of the study population according to spirometric patterns.
| Total (N = 23,615) | Normal spirometry (n = 20,742) | Mild-to-moderate RSP (n = 2758) | Severe RSP (n = 115) | P | |
|---|---|---|---|---|---|
| Age, years | 50.3 (0.2) | 49.7 (0.2) | 55.4 (0.4) | 64.1 (2.5) | < 0.001 |
| Sex, male | 45.4 (0.4) | 44.7 (0.4) | 50.6 (1.2) | 54.4 (5.6) | < 0.001 |
| BMI, kg/m2 | 24.3 (0.0) | 24.2 (0.0) | 25.3 (0.1) | 24.6 (0.5) | < 0.001 |
| Waist circumference, cm | 83.0 (0.1) | 82.5 (0.1) | 86.5 (0.3) | 85.9 (1.4) | < 0.001 |
| Smoking status | 0.022 | ||||
| Current smoker | 27.8 (0.4) | 27.6 (0.4) | 29.3 (1.2) | 26.3 (5.2) | |
| Ex-smoker | 12.7 (0.3) | 12.5 (0.3) | 14.5 (0.8) | 16.3 (4.3) | |
| Never-smoker | 59.5 (0.4) | 59.9 (0.4) | 56.2 (1.3) | 57.4 (5.7) | |
| Education level | < 0.001 | ||||
| High school or less | 71.5 (0.5) | 70.8 (0.6) | 76.4 (1.2) | 93.2 (2.2) | |
| College or above | 28.5 (0.5) | 29.2 (0.6) | 23.6 (1.2) | 6.8 (2.2) | |
| Marital status | 0.159 | ||||
| Married or living together | 80.1 (0.4) | 80.3 (0.5) | 79.0 (1.1) | 72.5 (5.7) | |
| Single/separated/divorced/widowed | 19.9 (0.4) | 19.7 (0.5) | 21.0 (1.1) | 27.5 (5.7) | |
| Family incomea | < 0.001 | ||||
| Low | 40.8 (0.6) | 39.8 (0.6) | 48.1 (1.3) | 62.9 (5.9) | |
| High | 59.2 (0.6) | 60.2 (0.6) | 51.9 (1.3) | 37.1 (5.9) | |
| Comorbidities | |||||
| Diabetes mellitus | 10.7 (0.2) | 9.4 (0.2) | 20.5 (0.9) | 30.2 (5.0) | < 0.001 |
| Hypertension | 32.9 (0.4) | 30.9 (0.4) | 48.3 (1.2) | 55.4 (5.9) | < 0.001 |
| Dyslipidemia | 41.1 (0.4) | 40.1 (0.4) | 49.1 (1.2) | 37.2 (5.1) | < 0.001 |
| Cardiovascular diseases | 3.2 (0.1) | 2.8 (0.1) | 6.3 (0.5) | 14.9 (3.9) | < 0.001 |
| Asthma | 1.9 (0.1) | 1.8 (0.1) | 2.9 (0.3) | 3.8 (1.7) | < 0.001 |
| Osteoporosis | 17.3 (0.7) | 16.3 (0.7) | 24.4 (1.9) | 27.0 (7.8) | < 0.001 |
| Osteoarthritis | 27.9 (0.5) | 26.9 (0.6) | 34.7 (1.5) | 40.2 (7.0) | < 0.001 |
| Malignancy | 3.6 (0.1) | 3.4 (0.1) | 4.8 (0.5) | 10.8 (3.3) | < 0.001 |
| Pulmonary function test | |||||
| FVC, L | 3.63 (0.0) | 3.72 (0.0) | 2.88 (0.0) | 1.95 (0.0) | < 0.001 |
| FVC, %predicted | 93.2 (0.1) | 95.7 (0.1) | 74.5 (0.1) | 54.1 (0.5) | < 0.001 |
| FEV1, L | 2.91 (0.0) | 2.99 (0.0) | 2.32 (0.0) | 1.55 (0.0) | < 0.001 |
| FEV1, %predicted | 93.9 (0.1) | 96.0 (0.1) | 78.0 (0.2) | 59.1 (0.8) | < 0.001 |
| FEV1/FVC | 0.80 (0.0) | 0.80 (0.0) | 0.81 (0.0) | 0.79 (0.0) | 0.068 |
Values are presented as mean (standard deviation) for age, BMI, waist circumference, and pulmonary function test and % (standard deviation) for other variables.
RSP restrictive spirometric pattern, BMI body mass index, FVC forced vital capacity, FEV1 forced expiratory volume in 1 s.
aFamily income levels were classified as upper half and lower half.