Table 1.
Characteristics of included participants.
| Characteristics | Overall (N = 7331) | Baseline PEF (L/min) | ||||
|---|---|---|---|---|---|---|
| Quartile 1 (N = 1897) | Quartile 2 (N = 1822) | Quartile 3 (N = 1806) | Quartile 4 (N = 1806) | P value | ||
| Baseline PEF, L/min | 290.00 (200.00, 370.00) | 160.00 (130.00, 180.00) | 250.00 (230.00, 270.00) | 330.00 (310.00, 350.00) | 450.00 (400.00;500.00) | <0.001* |
| Baseline PEF % predicted | 243.02 (213.24, 270.45) | 224.81 (190.09, 251.73) | 238.96 (209.23, 262.96) | 248.73 (224.85, 270.46) | 271.74 (242.85, 310.99) | <0.001* |
| Endpoint PEF, L/min | 300.00 (230.00, 380.00) | 220.00 (150.00, 290.00) | 270.00 (220.00, 330.00) | 320.00 (270.00, 380.00) | 420.00 (340.00, 480.00) | <0.001* |
| Endpoint PEF % predicted | 224.90 (192.06, 254.70) | 205.06 (168.55, 235.51) | 221.02 (190.20, 248.70) | 232.11 (205.07, 257.46) | 250.31 (213.26, 285.49) | <0.001* |
| Gender, n (%) | <0.001* | |||||
| Male | 3382 (46.13%) | 565 (29.78%) | 579 (31.78%) | 793 (43.91%) | 1445 (80.01%) | |
| Female | 3949 (53.87%) | 1332 (70.22%) | 1243 (68.22%) | 1013 (56.09%) | 361 (19.99%) | |
| Age, median (IQR) | 58.00 (51.00;64.00) | 62.00 (55.00;69.00) | 58.00 (52.00;65.00) | 56.00 (50.00;62.00) | 55.00 (49.00;61.00) | <0.001 |
| BMI, median (IQR) | 23.17 (20.90, 25.84) | 22.71 (20.18, 25.31) | 23.12 (20.74, 25.82) | 23.57 (21.27, 26.07) | 23.37 (21.31, 25.98) | <0.001* |
| Residence, n (%) | 0.019* | |||||
| Urban | 1138 (15.52%) | 284 (14.97%) | 250 (13.72%) | 291 (16.11%) | 313 (17.33%) | |
| Rural | 6193 (84.48%) | 1613 (85.03%) | 1572 (86.28%) | 1515 (83.89%) | 1493 (82.67%) | |
| Education level, n (%) | <0.001* | |||||
| Illiterate | 3459 (47.20%) | 1203 (63.45%) | 987 (54.17%) | 804 (44.52%) | 465 (25.76%) | |
| Primary school or below | 1687 (23.02%) | 378 (19.94%) | 411 (22.56%) | 417 (23.09%) | 481 (26.65%) | |
| Middle school | 1492 (20.357%) | 218 (11.498%) | 311 (17.069%) | 394 (21.816%) | 569 (31.524%) | |
| High school or above | 691 (9.428%) | 97 (5.116%) | 113 (6.202%) | 191 (10.576%) | 290 (16.066%) | |
| Marital status (n, %) | <0.001* | |||||
| Married/cohabitating | 776 (10.59%) | 312 (16.45%) | 199 (10.92%) | 157 (8.69%) | 108 (5.98%) | |
| Divorced/separated/widowed/never married | 6555 (89.42%) | 1585 (83.55%) | 1623 (89.08%) | 1649 (91.31%) | 1698 (94.02%) | |
| Smoking status, n (%) | <0.001* | |||||
| Never smoke | 4496 (61.33%) | 1321 (69.64%) | 1302 (71.46%) | 1145 (63.40%) | 728 (40.31%) | |
| Former/Current smoke | 2835 (38.67%) | 576 (30.36%) | 520 (28.54%) | 661 (36.60%) | 1078 (59.69%) | |
| Drinking status, n (%) | <0.001* | |||||
| Never drink | 4346 (59.28%) | 1256 (66.21%) | 1247 (68.44%) | 1104 (61.13%) | 739 (40.92%) | |
| Former/Current drink | 2985 (40.72%) | 641 (33.79%) | 575 (31.56%) | 702 (38.87%) | 1067 (59.08%) | |
| Hypertension (n, %) | 1829 (24.95%) | 537 (28.31%) | 466 (25.58%) | 430 (23.81%) | 396 (21.93%) | 0.001* |
| Dyslipidemia (n, %) | 714 (9.74%) | 168 (8.86%) | 157 (8.62%) | 201 (11.13%) | 188 (10.41%) | 0.014* |
| Heart disease (n, %) | 826 (11.27%) | 290 (15.29%) | 200 (10.98%) | 179 (9.91%) | 157 (8.69%) | <0.001* |
| Diabetes (n, %) | 426 (5.81%) | 117 (6.17%) | 103 (5.65%) | 121 (6.70%) | 85 (4.71%) | 0.094 |
| Stroke (n, %) | 147 (2.01%) | 45 (2.37%) | 42 (2.31%) | 40 (2.22%) | 20 (1.11%) | 0.097 |
| Lung disease (n, %) | 656 (8.948%) | 305 (16.078%) | 155 (8.507%) | 123 (6.811%) | 73 (4.042%) | <0.001* |
| VI (n, %) | 5542 (75.60%) | 1507 (79.44%) | 1445 (79.31%) | 1363 (75.47%) | 1227 (67.94%) | <0.001* |
| DVI (n, %) | 4515 (61.59%) | 1298 (68.42%) | 1201 (65.92%) | 1075 (59.52%) | 941 (52.10%) | <0.001* |
| NVI (n, %) | 4774 (65.12%) | 1294 (68.21%) | 1253 (68.77%) | 1186 (65.67%) | 1041 (57.64%) | <0.001* |
| HI (n, %) | 3852 (52.54%) | 1110 (58.51%) | 1000 (54.89%) | 910 (50.39%) | 832 (46.07%) | <0.001* |
| SI status | <0.001* | |||||
| Non-SI (n, %) | 1396 (19.04%) | 293 (15.45%) | 288 (15.81%) | 348 (19.27%) | 467 (25.86%) | |
| SI (n, %) | 2476 (33.77%) | 591 (31.15%) | 623 (34.19%) | 643 (35.60%) | 619 (34.28%) | |
| DSI (n, %) | 3459 (47.18%) | 1013 (53.40%) | 911 (50.00%) | 815 (45.13%) | 720 (39.87%) | |
PEF peak expiratory flow, VI visual impairment, DVI distance vision impairment, NVI near vision impairment, HI hearing impairment, Non-SI non-sensory impairment, SSI single sensory impairment, DSI dual sensory impairment.
*p < 0.05.