Table 1. Clinical characteristics of the study population by the status of restrictive spirometry pattern.
| RSP negative (n = 20,791) | RSP positive (n = 2,398) | P | |
|---|---|---|---|
| Age (years) | 54.9 ± 12.2 | 58.5 ± 12.4 | <0.001 |
| Men, n (%) | 9,169, (44.1) | 1,159, (48.3) | <0.001 |
| Current smoking, n (%) | 3,955, (19.4) | 452, (19.1) | 0.769 |
| Alcohol drinking, n (%) | 4,627, (22.7) | 493, (20.9) | 0.042 |
| College graduate, n (%) | 4,935, (24.4) | 491, (20.9) | <0.001 |
| High monthly income, n (%) | 5,257, (25.5) | 491, (20.7) | <0.001 |
| High mental stress, n (%) | 4,841, (23.7) | 533, (22.6) | 0.210 |
| Pulmonary TB, n (%) | 1,000, (4.9) | 176, (7.5) | <0.001 |
| Bronchial asthma, n (%) | 611, (3.0) | 76, (3.2) | 0.574 |
| Allergic rhinitis, n (%) | 2,142, (10.6) | 182, (7.7) | <0.001 |
| Atopic dermatitis, n (%) | 305, (1.5) | 35, (1.5) | 0.940 |
| Raised BP, n (%) | 7,651, (36.8) | 1,100, (45.9) | <0.001 |
| Systolic BP (mm Hg) | 122.0 ± 16.7 | 126.9 ± 17.7 | <0.001 |
| Diastolic BP (mm Hg) | 77.6 ± 10.2 | 78.4 ± 10.7 | 0.001 |
| Raised fasting glucose, n (%) | 7,480, (36.5) | 1,180, (49.6) | <0.001 |
| Fasting glucose (mmol/l) | 5.6 ± 1.3 | 5.9 ± 1.5 | <0.001 |
| Raised triglyceride, n (%) | 6,744, (32.4) | 955, (39.8) | <0.001 |
| Triglyceride (mmol/l) | 1.6 ± 1.2 | 1.8 ± 1.3 | <0.001 |
| Reduced HDL-C, n (%) | 8,519, (41.4) | 1,170, (49.4) | <0.001 |
| HDL-C (mmol/l) | 1.3 ± 0.3 | 1.2 ± 0.3 | <0.001 |
| Central obesity, n (%) | 8,361, (40.2) | 1,365, (57.0) | <0.001 |
| Waist circumference (cm) | 82.5 ± 8.9 | 86.3 ± 10.3 | <0.001 |
| BMI (kg/m2) | 24.1 ± 3.0 | 25.3 ±3.7 | <0.001 |
| Metabolic syndrome, n (%) | 6,478, (31.9) | 1,155, (49.3) | <0.001 |
| Previous CV disease, n (%) | 796, (3.9) | 173, (7.3) | <0.001 |
| FVC (L) | 3.6 ± 0.9 | 2.8 ± 0.7 | <0.001 |
| FVC (%-predicted) | 95.0 ± 10.3 | 73.9 ± 6.0 | <0.001 |
| FEV1 (L) | 2.8 ± 0.7 | 2.2 ± 0.5 | <0.001 |
| FEV1 (%-predicted) | 94.1 ± 12.9 | 78.1 ± 8.3 | <0.001 |
| FEV1/FVC | 0.78 ± 0.08 | 0.80 ± 0.06 | <0.001 |
| WBC (×103/μl) | 6.03 ± 1.70 | 6.31 ± 1.76 | <0.001 |
| Hemoglobin (g/dl) | 14.0 ± 1.5 | 14.0 ± 1.6 | 0.405 |
| GHF, n (%) | 2,031, (9.8) | 284 (11.8) | 0.001 |
| eGFR (ml/min/1.73m2) | 91.1 ± 14.9 | 87.7 ± 16.6 | <0.001 |
| Proteinuria, n (%) | 218, (1.1) | 48, (2.1) | <0.001 |
RSP, respiratory spirometry pattern; TB, tuberculosis; BP, blood pressure; HDL-C, high density lipoprotein cholesterol; BMI, body mass index; CV, cardiovascular; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 second; WBC, white blood cells; eGFR, estimated glomerular filtration rate; GHF, glomerular hyperfiltration. Values are expressed as mean ± standard deviation for continuous variables. Difference was analyzed by Student t-test for continuous variables and a chi-square test for categorical variables.