Prevalence of alcohol use depending on smoking and prevalence of smoking depending on alcohol use among Japanese adolescents (aged 12–18 years) between 1996 and 2017 by sex
| Year | 1996 | 2000 | 2004 | 2008 | 2012 | 2017 | Reduction rate† | ||
| %* 95% CI | %* 95% CI | %* 95% CI | %* 95% CI | %* 95% CI | %* 95% CI | ||||
| Alcohol use in the past 30 days | Boys | Non-smokers | 30.4 (30.3 to 30.5) | 30.1 (30.1 to 30.2) | 23.0 (22.9 to 23.0) | 12.7 (12.7 to 12.8) | 9.0 (9.0 to 9.1) | 4.3 (4.3 to 4.3) | 0.86 |
| Smokers | 72.0 (71.9 to 72.1) | 72.0 (71.9 to 72.1) | 72.5 (72.4 to 72.7) | 66.3 (66.1 to 66.5) | 64.8 (64.5 to 65.0) | 55.3 (54.9 to 55.7) | 0.23 | ||
| Girls | Non-smokers | 27.8 (27.7 to 27.8) | 29.1 (29.1 to 29.2) | 23.7 (23.7 to 23.8) | 13.8 (13.8 to 13.8) | 10.7 (10.7 to 10.8) | 3.7 (3.7 to 3.8) | 0.87 | |
| Smokers | 76.7 (76.5 to 76.9) | 76.3 (76.2 to 76.5) | 77.0 (76.8 to 77.2) | 73.7 (73.5 to 74.0) | 79.5 (79.2 to 79.9) | 62.0 (61.5 to 62.5) | 0.19 | ||
| Both | Non-smokers | 29.0 (29.0 to 29.0) | 29.6 (29.6 to 29.6) | 23.4 (23.3 to 23.4) | 13.3 (13.2 to 13.3) | 9.9 (9.8 to 9.9) | 4.0 (4.0 to 4.0) | 0.86 | |
| Smokers | 73.3 (73.2 to 73.4) | 73.3 (73.2 to 73.4) | 74.1 (74.0 to 74.2) | 68.7 (68.6 to 68.9) | 69.2 (69.0 to 69.4) | 57.4 (57.1 to 57.7) | 0.22 | ||
| Smoking in the past 30 days | Boys | Non-drinkers | 10.6 (10.6 to 10.7) | 9.2 (9.1 to 9.2) | 4.0 (4.0 to 4.1) | 2.5 (2.5 to 2.5) | 1.4 (1.4 to 1.5) | 1.0 (1.0 to 1.0) | 0.91 |
| Drinkers | 41.2 (41.1 to 41.3) | 37.6 (37.5 to 37.7) | 27.1 (27.0 to 27.2) | 25.8 (25.7 to 25.9) | 21.3 (21.2 to 21.5) | 22.1 (21.9 to 22.3) | 0.46 | ||
| Girls | Non-drinkers | 3.1 (3.1 to 3.1) | 3.4 (3.3 to 3.4) | 1.9 (1.8 to 1.9) | 1.0 (1.0 to 1.0) | 0.4 (0.4 to 0.4) | 0.4 (0.4 to 0.4) | 0.87 | |
| Drinkers | 21.4 (21.3 to 21.5) | 21.4 (21.3 to 21.5) | 17.0 (16.9 to 17.1) | 15.1 (15.0 to 15.2) | 11.2 (11.1 to 11.3) | 14.8 (14.6 to 15.0) | 0.31 | ||
| Both | Non-drinkers | 6.7 (6.7 to 6.7) | 6.2 (6.2 to 6.2) | 3.0 (2.9 to 3.0) | 1.8 (1.8 to 1.8) | 0.9 (0.9 to 0.9) | 0.7 (0.7 to 0.7) | 0.90 | |
| Drinkers | 32.5 (32.4 to 32.5) | 30.2 (30.1 to 30.2) | 22.2 (22.2 to 22.3) | 20.6 (20.5 to 20.7) | 16.2 (16.1 to 16.3) | 18.9 (18.8 to 19.0) | 0.42 | ||
*Adjusted for grade and sex.
†Reduction rate = (prevalence in 1996 − prevalence in 2017)/prevalence in 1996.