Baseline characteristics of the study participants
| N | All participants | Normal spirometry | Impaired spirometry* | P value |
| 464 | 319 | 145 | ||
| Age (years) | 55.09 (±10.45) | 54.79 (±10.86) | 55.76 (±9.49) | 0.330 |
| Sex (%) | <0.001 | |||
| Female | 314 (67.7%) | 193 (60.5%) | 121 (83.4%) | |
| Male | 150 (32.3%) | 126 (39.5%) | 24 (16.6%) | |
| Education (%) | 0.412 | |||
| Below secondary education | 196 (56.6%) | 125 (55.1%) | 71 (59.7%) | |
| Secondary/tertiary education | 150 (43.4%) | 102 (44.9%) | 48 (40.3%) | |
| Smoking status | 0.892 | |||
| Never smoker | 455 (98.1%) | 313 (98.1%) | 142 (97.9%) | |
| Current/previous smoker | 9 (1.9%) | 6 (1.9%) | 3 (2.1%) | |
| Smoking pack years† | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 0.0 (0.0–0.0) | 0.889 |
| Diabetes duration (years) | 10.00 (±7.36) | 9.11 (±7.20) | 12.21 (±7.30) | <0.001 |
| Insulin use (%) | 139 (30.0%) | 92 (28.8%) | 47 (32.4%) | 0.436 |
| Statin use (%) | 192 (41.4%) | 124 (38.9%) | 68 (46.9%) | 0.104 |
| Obesity (%) | 169 (36.4%) | 107 (33.5%) | 62 (42.8%) | 0.056 |
| BMI, kg/m2 | 29.13 (±6.00) | 28.71 (±5.56) | 30.04 (±6.78) | 0.040 |
| Hypertension (%) | 199 (42.9%) | 123 (38.6%) | 76 (52.4%) | 0.005 |
| Systolic BP, mm Hg | 135.26 (±15.67) | 134.62 (±15.04) | 136.65 (±16.93) | 0.196 |
| Diastolic BP, mm Hg | 79.14 (±8.23) | 78.95 (±8.23) | 79.55 (±8.23) | 0.468 |
| Heart rate, bpm | 79.36 (±10.72) | 79.34 (±10.73) | 79.40 (±10.75) | 0.952 |
| Suboptimal BP control (%) | 323 (69.6%) | 214 (67.1%) | 109 (75.2%) | 0.079 |
| Biochemical measures | ||||
| HbA1c, % | 7.98 (±1.77) | 7.85 (±1.79) | 8.23 (±1.71) | 0.046 |
| Total cholesterol, mmol/L | 4.86 (±1.27) | 4.80 (±1.28) | 4.97 (±1.26) | 0.271 |
| Triglyceride, mmol/L | 1.22 (±0.50) | 1.23 (±0.53) | 1.22 (±0.45) | 0.813 |
| HDL-cholesterol, mmol/L | 1.34 (±0.35) | 1.33 (±0.35) | 1.35 (±0.35) | 0.671 |
| LDL-cholesterol, mmol/L | 2.95 (±1.15) | 2.90 (±1.15) | 3.04 (±1.16) | 0.299 |
| eGFR, mL/min/1.73m2 | 97.43 (±22.39) | 97.43 (±22.21) | 97.44 (±22.84) | 0.997 |
Suboptimal BP control was defined per the 2017 American College of Cardiology/American Heart Association guidelines criteria and European Society of Cardiology/European Society of Hypertension guidelines (for individuals with hypertension and diabetes) as systolic BP ≥130 mm Hg and/or diastolic BP ≥80 mm Hg.
*Impaired spirometry defined as the presence of pulmonary restriction and/or airway obstruction.
†Data presented as median (IQR).
BMI, body mass index; BP, blood pressure; bpm, beats per minute; eGFR, estimated glomerular filtration rate; FEF25-75%, forced expiratory flow at 25% point to the 75% point of forced vital capacity; FEV1, forced expiratory volume in 1 s; FEV1/FVC, ratio of FEV1 to FVC; FVC, forced vital capacity; HbA1c, glycated haemoglobin; HDL, high-density lipoprotein; LDL, low-density lipoprotein.