| |
None
|
1–2 times
|
Sometimes
|
Once a week
|
More than 2–3 times a week
| |
|---|
| |
N
|
(%)
|
N
|
(%)
|
N
|
(%)
|
N
|
(%)
|
N
|
(%)
| |
|---|
|
Totala
|
2713
|
(93.5)
|
84
|
(2.9)
|
66
|
(2.3)
|
7
|
(0.2)
|
32
|
(1.1)
| |
|
Boys
|
1350
|
(92.1)
|
47
|
(3.2)
|
41
|
(2.8)
|
4
|
(0.3)
|
24
|
(1.6)
|
**b
|
|
Girls
|
1363
|
(94.9)
|
37
|
(2.6)
|
25
|
(1.7)
|
3
|
(0.2)
|
8
|
(0.6)
| |
|
Gradea
| | | | | | | | | | |
**d
|
|
7th
|
843
|
(95.9)
|
18
|
(2.0)
|
15
|
(1.7)
|
2
|
(0.2)
|
1
|
(0.1)
| |
|
Boys
|
426
|
(95.7)
|
9
|
(2.0)
|
8
|
(1.8)
|
1
|
(0.2)
|
1
|
(0.2)
| |
|
Girls
|
417
|
(96.1)
|
9
|
(2.1)
|
7
|
(1.6)
|
1
|
(0.2)
|
0
|
(0)
| |
|
8th
|
935
|
(92.9)
|
35
|
(3.5)
|
21
|
(2.1)
|
4
|
(0.4)
|
12
|
(1.2)
|
**e
|
|
Boys
|
449
|
(90.5)
|
20
|
(4.0)
|
14
|
(2.8)
|
3
|
(0.6)
|
10
|
(2.0)
|
*c
|
|
Girls
|
486
|
(95.1)
|
15
|
(2.9)
|
7
|
(1.4)
|
1
|
(0.2)
|
2
|
(0.4)
| |
|
9th
|
935
|
(92.0)
|
31
|
(3.1)
|
30
|
(3.0)
|
1
|
(0.1)
|
19
|
(1.9)
|
***f
|
|
Boys
|
475
|
(90.5)
|
18
|
(3.4)
|
19
|
(3.6)
|
0
|
(0)
|
13
|
(2.5)
| |
|
Girls
|
460
|
(93.7)
|
13
|
(2.6)
|
11
|
(2.2)
|
1
|
(0.2)
|
6
|
(1.2)
| |
- Prevalence of tobacco use in the last six months among Japanese adolescent boys and girls by grade are shown.
- Significant at * p < 0.05; ** p < 0.01; *** p < 0.001 (two-tailed).
- a Does not total 2,923 due to missing data. (N = 2,902)
- b In the two-independent-sample tests by the Mann-Whitney U test among gender, the prevalence among boys was significantly higher than among girls.
- c In 8th graders, the prevalence among boys was significantly higher than among girls.
- d In the multiple comparison tests by the Kruskal Wallis test, there was significant difference among grades.
- e In the two-independent-sample tests by the Mann-Whitney U test between each of the two grades, the prevalence among 8th graders was higher than among 7th graders.
- f The prevalence among 9th graders was higher than among 7th graders.
