Table 2.
Baseline characteristics stratified by baseline drinking water sources after PSM, IPTW, and overlap weighing.
| Variable | After PSM | After IPTW | After overlap weighting | ||||||
|---|---|---|---|---|---|---|---|---|---|
| To tap water | To natural water | ASD | To tap water | To natural water | ASD | To tap water | To natural water | ASD | |
| (n = 9,124) | (n = 9,124) | (n = 11,422) | (n = 15,282.4) | (n = 5,738.6) | (n = 5,738.6) | ||||
| Sex: female | 5,597 (61.3) | 5,314 (58.2) | 0.063 | 6,911.1 (60.5) | 9,234.2 (60.4) | 0.002 | 3,485.2 (60.7) | 3,485.2 (60.7) | <0.001 |
| Age (years) | 91.00 (83.00, 100.00) | 91.00 (81.00, 100.00) | 0.079 | 91.00 (83.00, 100.00) | 91.00 (82.00, 100.00) | <0.001 | 91.00 (83.00, 100.00) | 91.00 (82.00, 100.00) | <0.001 |
| Education: 1 year or more | 2,551 (28.0) | 2,646 (29.0) | 0.023 | 3,220.2 (28.2) | 4,306.8 (28.2) | <0.001 | 1,607.7 (28.0) | 1,607.7 (28.0) | <0.001 |
| Marital status: not in marriage | 6,942 (76.1) | 6,724 (73.7) | 0.055 | 8,619.7 (75.5) | 11,552.8 (75.6) | 0.003 | 4,346.2 (75.7) | 4,346.2 (75.7) | <0.001 |
| Residence: rural | 6,481 (71.0) | 6,667 (73.1) | 0.045 | 8,271.2 (72.4) | 11,051.5 (72.3) | 0.002 | 4,171.1 (72.7) | 4,171.1 (72.7) | <0.001 |
| Current smoking: yes | 1564 (17.1) | 1,784 (19.6) | 0.062 | 2,082.8 (18.2) | 2,777.1 (18.2) | 0.002 | 1,020.2 (17.8) | 1,020.2 (17.8) | <0.001 |
| Current drinking: yes | 1,909 (20.9) | 2,106 (23.1) | 0.052 | 2,470.1 (21.6) | 3,286.0 (21.5) | 0.003 | 1,221.6 (21.3) | 1,221.6 (21.3) | <0.001 |
| Current regular exercise: yes | 2,009 (22.0) | 2,093 (22.9) | 0.022 | 2,481.2 (21.7) | 3,328.1 (21.8) | 0.001 | 1,242.7 (21.7) | 1,242.7 (21.7) | <0.001 |
| Hypertension | 0.055 | 0.002 | <0.001 | ||||||
| No | 7,460 (81.8) | 7,327 (80.3) | 9,325.1 (81.6) | 12,484.4 (81.7) | 4,686.4 (81.7) | 4,686.4 (81.7) | |||
| Yes | 1,259 (13.8) | 1,286 (14.1) | 1,537.8 (13.5) | 2,057.0 (13.5) | 785.5 (13.7) | 785.5 (13.7) | |||
| Unknown | 405 (4.4) | 511 (5.6) | 559.1 (4.9) | 741.1 (4.8) | 266.7 (4.6) | 266.7 (4.6) | |||
| Diabetes | 0.051 | 0.005 | <0.001 | ||||||
| No | 8,619 (94.5) | 8,513 (93.3) | 10,726.9 (93.9) | 14,368.4 (94.0) | 5,404.5 (94.2) | 5,404.5 (94.2) | |||
| Yes | 91 (1.0) | 95 (1.0) | 118.3 (1.0) | 153.3 (1.0) | 58.4 (1.0) | 58.4 (1.0) | |||
| Unknown | 414 (4.5) | 516 (5.7) | 576.9 (5.1) | 760.8 (5.0) | 275.7 (4.8) | 275.7 (4.8) | |||
| Heart diseases | 0.053 | 0.003 | <0.001 | ||||||
| No | 8,235 (90.3) | 8,106 (88.8) | 10,261.2 (89.8) | 13,728.0 (89.8) | 5,166.5 (90.0) | 5,166.5 (90.0) | |||
| Yes | 490 (5.4) | 521 (5.7) | 610.9 (5.3) | 824.3 (5.4) | 309.1 (5.4) | 309.1 (5.4) | |||
| Unknown | 399 (4.4) | 497 (5.4) | 549.9 (4.8) | 730.1 (4.8) | 263.1 (4.6) | 263.1 (4.6) | |||
| Cerebrovascular diseases | 0.058 | 0.004 | <0.001 | ||||||
| No | 8,421 (92.3) | 8,313 (91.1) | 10,498.5 (91.9) | 14,048.3 (91.9) | 5,286.0 (92.1) | 5,286.0 (92.1) | |||
| Yes | 336 (3.7) | 333 (3.6) | 409.5 (3.6) | 554.9 (3.6) | 207.6 (3.6) | 207.6 (3.6) | |||
| Unknown | 367 (4.0) | 478 (5.2) | 514.0 (4.5) | 679.2 (4.4) | 245.0 (4.3) | 245.0 (4.3) | |||
| Respiratory diseases | 0.071 | 0.003 | <0.001 | ||||||
| No | 7,838 (85.9) | 7,638 (83.7) | 9,697.1 (84.9) | 12,989.9 (85.0) | 4,897.3 (85.3) | 4,897.3 (85.3) | |||
| Yes | 949 (10.4) | 1,035 (11.3) | 1,253.4 (11.0) | 1,665.2 (10.9) | 617.3 (10.8) | 617.3 (10.8) | |||
| Unknown | 337 (3.7) | 451 (4.9) | 471.6 (4.1) | 627.3 (4.1) | 224.0 (3.9) | 224.0 (3.9) | |||
| Cancer | 0.071 | 0.002 | <0.001 | ||||||
| No | 8,662 (94.9) | 8,515 (93.3) | 10,772.3 (94.3) | 14,417.6 (94.3) | 5,432.0 (94.7) | 5,432.0 (94.7) | |||
| Yes | 28 (0.3) | 27 (0.3) | 32.6 (0.3) | 42.6 (0.3) | 16.7 (0.3) | 16.7 (0.3) | |||
| Unknown | 434 (4.8) | 582 (6.4) | 617.1 (5.4) | 822.2 (5.4) | 289.9 (5.1) | 289.9 (5.1) | |||
Values are median (IQR) or n (%).
ASD, absolute standardized mean differences; IPTW, inverse probability treatment weighting; PSM, propensity score matching.
Because the table is too large, some baseline information was included in the Supplementary Table S4.