Table 1 Demographic and exposure variables in a sample of Chinese adolescents (N = 1609)
Variables | N | % |
|---|---|---|
Total | 1609 | 100 |
Gender | ||
  Male | 588 | 36.5 |
  Female | 1021 | 63.5 |
Age(yr) | ||
   ≤ 15 | 243 | 15.1 |
  16 | 526 | 32.7 |
  17 | 552 | 34.3 |
  18 | 288 | 17.9 |
Grade | ||
  10 | 485 | 30.1 |
  11 | 692 | 43.0 |
  12 | 432 | 26.9 |
Only-child status | ||
  Yes | 397 | 24.7 |
  No | 1212 | 75.3 |
Someone in the community is infected | ||
  Yes | 92 | 5.7 |
  No | 1517 | 94.3 |
A relative or friend is infected | ||
  Yes | 13 | 0.8 |
  No | 1596 | 99.2 |
A relative or friend died from the infection | ||
  Yes | 3 | 0.2 |
  No | 1606 | 99.8 |
Smoker | ||
  Yes | 31 | 19.3 |
  No | 1578 | 80.7 |
Drinker | ||
  Yes | 93 | 5.8 |
  No | 1516 | 94.2 |