Table 1. General Characteristics of Participants.
| Characteristics | The Number of participants (matched 1:4) | ||
|---|---|---|---|
| Tonsillectomy group | Control group | Total participants | |
| Age (years old) | |||
| 0–4 | 1,661 | 6,644 | 8,305 |
| 5–9 | 1,089 | 4,356 | 5,445 |
| 10–14 | 692 | 2,768 | 3,460 |
| 15–19 | 521 | 2,084 | 2,605 |
| 20–24 | 460 | 1,840 | 2,300 |
| 25–29 | 412 | 1,648 | 2,060 |
| 30–34 | 331 | 1,324 | 1,655 |
| 35–39 | 225 | 900 | 1,125 |
| 40–44 | 184 | 736 | 920 |
| 45–49 | 124 | 496 | 620 |
| 50–54 | 56 | 224 | 280 |
| 55–59 | 44 | 176 | 220 |
| 60–64 | 27 | 108 | 135 |
| 65–69 | 4 | 16 | 20 |
| 70–74 | 0 | 0 | 0 |
| 75–79 | 1 | 4 | 5 |
| Sex | |||
| Male | 3,432 | 13,728 | 17,160 |
| Female | 2,399 | 9,596 | 11,995 |
| Income | |||
| 1 (lowest) | 50 | 200 | 250 |
| 2 | 215 | 860 | 1,075 |
| 3 | 270 | 1,080 | 1,350 |
| 4 | 365 | 1,460 | 1,825 |
| 5 | 495 | 1,980 | 2,475 |
| 6 | 569 | 2,276 | 2,845 |
| 7 | 669 | 2,676 | 3,345 |
| 8 | 790 | 3,160 | 3,950 |
| 9 | 835 | 3,340 | 4,175 |
| 10 | 838 | 3,352 | 4,190 |
| 11 (highest) | 735 | 2,940 | 3,675 |
| Region of residence | |||
| Urban | 2,634 | 10,536 | 13,170 |
| Rural | 3,197 | 12,788 | 15,985 |