Table 1. Demographic characteristics of study participants by school level.
| Total§ | Middle school, Grade 7 | High school, Grade 7 | |||
|---|---|---|---|---|---|
| Male§ | Female§ | Male§ | Female§ | ||
| Total | 2,879 (100.0) | 852 (100.0) | 720 (100.0) | 659 (100.0) | 648 (100.0) |
| Household income per month, $US | |||||
| < 2,000 | 77 (2.3) | 22 (2.7) | 17 (2.8) | 22 (1.4) | 16 (2.1) |
| 2,000–3,000 | 323 (9.8) | 77 (7.4) | 79 (10.1) | 80 (10.1) | 87 (12.2) |
| 3,000–4,000 | 1,133 (39.2) | 338 (35.9) | 293 (40.9) | 236 (39.9) | 266 (40.6) |
| ≥ 4,000 | 962 (35.9) | 309 (38.9) | 259 (36.9) | 195 (33.7) | 199 (33.8) |
| Missing | 384 (12.8) | 106 (15.1) | 72 (9.4) | 126 (15.0) | 80 (11.3) |
| Cigarette smoking status | |||||
| Never | 2,534 (89.0) | 754 (91.5) | 677 (95.1) | 493 (76.0) | 610 (94.1) |
| Ever | 323 (10.8) | 82 (7.9) | 37 (4.6) | 166 (24.0) | 38 (5.9) |
| Missing | 22 (0.2) | 16 (0.6) | 6 (0.2) | 0 (0) | 0 (0) |
| Alcohol use | |||||
| Never | 2,310 (81.0) | 756 (89.3) | 665 (93.6) | 420 (64.6) | 469 (75.4) |
| Ever | 543 (18.8) | 77 (10.0) | 48 (6.1) | 239 (35.4) | 179 (24.6) |
| Missing | 26 (0.3) | 19 (0.7) | 7 (0.3) | 0 (0) | 0 (0) |
| History of sinusitis | |||||
| Yes | 265 (9.3) | 63 (9.1) | 49 (5.9) | 85 (12.2) | 68 (10.3) |
| No | 2,358 (81.5) | 687 (78.5) | 616 (87.8) | 518 (78.5) | 537 (81.2) |
| Missing | 256 (9.2) | 102 (12.4) | 55 (6.4) | 56 (9.3) | 43 (8.4) |
| Took medication for sinusitis in past 2 weeks | |||||
| Yes | 41 (1.5) | 13 (2.0) | 9 (0.9) | 11 (2.4) | 8 (0.8) |
| No | 2,299 (80.2) | 667 (78.0) | 593 (84.9) | 525 (80.7) | 514 (76.7) |
| Missing | 539 (18.3) | 172 (20.0) | 118 (14.2) | 123 (16.9) | 126 (22.5) |
| History of ear infection | |||||
| Yes | 295 (9.8) | 69 (7.5) | 78 (10.3) | 67 (8.8) | 81 (13.4) |
| No | 2,317 (80.4) | 677 (79.0) | 590 (83.9) | 535 (81.5) | 515 (76.7) |
| Missing | 267 (9.8) | 106 (13.5) | 52 (5.8) | 57 (9.7) | 52 (9.9) |
| Took medication for otitis media in past 2 weeks | |||||
| Yes | 21 (0.6) | 9 (0.7) | 7 (1.0) | 2 (0.1) | 3 (0.5) |
| No | 2,307 (80.4) | 667 (77.6) | 597 (85.1) | 531 (82.7) | 512 (75.8) |
| Missing | 551 (19.0) | 176 (21.7) | 116 (13.9) | 126 (17.1) | 133 (23.8) |
| Subjective hearing discomfort | |||||
| None | 2,279 (79.5) | 689 (81.3) | 568 (80.8) | 522 (77.9) | 500 (77.7) |
| Mild-to-moderate | 427 (15.2) | 94 (11.8) | 105 (13.8) | 108 (18.0) | 120 (17.5) |
| Severe | 11 (0.4) | 1 (0.1) | 1 (0.1) | 5 (0.6) | 4 (0.7) |
| Profound | |||||
| Missing | 162 (4.9) | 68 (6.7) | 46 (5.2) | 24 (3.4) | 24 (4.1) |
| Has hearing aid | |||||
| Yes | 14 (0.2) | 9 (0.6) | 3 (0.2) | 1 (0.02) | 1 (0.1) |
| Yes, but do not use | 4 (0.02) | 1 (0.04) | 1 (0.04) | 1 (0.002) | 1 (0) |
| No | 885 (30.3) | 233 (26.1) | 196 (25.3) | 230 (36.8) | 226 (33.8) |
| Missing | 1,976 (69.4) | 609 (73.3) | 520 (74.5) | 427 (63.2) | 420 (66) |
| Tinnitus | |||||
| Yes | 1,298 (43.9) | 247 (27.0) | 319 (45.0) | 310 (45.0) | 422 (62.6) |
| No | 1,035 (37.5) | 430 (53.8) | 240 (33.9) | 232 (37.3) | 133 (21.5) |
| I don’t know | 416 (14.6) | 116 (13.8) | 126 (17.7) | 90 (13.1) | 84 (13.8) |
| Missing | 130 (4.0) | 59 (5.4) | 35 (3.3) | 27 (4.7) | 9 (2.2) |
| Personal stereo usage | |||||
| Yes | 2,518 (87.1) | 666 (76.8) | 638 (89.2) | 596 (89.7) | 618 (94.3) |
| No | 345 (12.8) | 175 (22.8) | 77 (10.6) | 63 (10.3) | 30 (5.7) |
| Missing | 16 (0.2) | 11 (0.4) | 5 (0.2) | 0 (0) | 0 (0) |
| Type of personal stereo | |||||
| With earphones | 2,330 (80.8) | 575 (67.6) | 596 (83.0) | 553 (83.0) | 606 (92.3) |
| Any other device With headphones |
152 (5.2) | 77 (8.0) | 30 (4.7) | 36 (5.8) | 9 (1.8) |
| Not applicable | 361 (12.9) | 186 (23.2) | 82 (10.8) | 63 (10.3) | 30 (5.7) |
| Missing | 36 (1.0) | 14 (1.2) | 12 (1.5) | 7 (1.0) | 3 (0.2) |
| Usage period | |||||
| Not applicable | 345 (12.8) | 175 (22.8) | 77 (10.6) | 63 (10.3) | 30 (5.7) |
| 0–4 years | 1,379 (48.3) | 499 (57.7) | 421 (58.7) | 269 (41.9) | 190 (31.8) |
| ≥ 4 years | 1,139 (38.8) | 167 (19.1) | 217 (30.5) | 327 (47.8) | 428 (62.5) |
| Missing | 16 (0.2) | 11 (0.4) | 5 (0.2) | 0 (0) | 0 (0) |
| Volume level | |||||
| Not applicable | 345 (12.8) | 175 (22.8) | 77 (10.6) | 63 (10.3) | 30 (5.7) |
| 0–4 | 1,446 (52.2) | 375 (42.3) | 384 (56.3) | 336 (55.9) | 351 (55.5) |
| 5–9 | 1,072 (34.8) | 291 (34.5) | 254 (32.9) | 260 (33.7) | 267 (38.8) |
| Missing | 16 (0.2) | 11 (0.4) | 5 (0.2) | 0 (0) | 0 (0) |
| Request to turn down the volume | |||||
| Ever experienced | 401 (14.0) | 76 (9.4) | 121 (18.3) | 88 (12.5) | 116 (16.8) |
| Never experienced | 2,062 (71.4) | 572 (65.7) | 497 (69.2) | 500 (75.9) | 493 (75.7) |
| Missing | 416 (14.6) | 204 (24.9) | 102 (12.6) | 71 (11.6) | 39 (7.5) |
| Usage of noisy facility in the past year | |||||
| LAN gaming center | 1,701 (59.8) | 568 (66.1) | 224 (31.8) | 576 (88.6) | 333 (50.4) |
| Karaoke room | 2072 (74.7) | 392 (48.5) | 624 (87.7) | 482 (76.9) | 574 (89.7) |
| Concert auditorium | 370 (12.3) | 50 (6.2) | 114 (14.8) | 60 (7.3) | 146 (23.2) |
| Dance club | 8 (0.3) | 1 (0.02) | 1 (0.04) | 4 (1.0) | 2 (0.3) |
§ Unweighted frequencies with weighted percentages.