Table 2. Characteristics of male initial sample and follow-up samples.
| Percentage or mean (95%CI) | ||||||
|---|---|---|---|---|---|---|
| Initial (18–19 years old) n = 371 |
2-year follow-up (20–21 years old) n = 206 (55.5%) |
4-year follow-up (22–23 years old) n = 139 (37.5%) |
6-year follow-up (24–25 years old) n = 81 (21.8%) |
9-year follow-up (27–28 years old) n = 90 (24.2%) |
p-value | |
| Maternal educational level | ||||||
| Primary school | 32.0 (26.5–37.8) | 35.8 (28.4–43.3) | 41.6 (32.8–50.8) | 43.0 (31.6–54.8) | 41.6 (31.5–53.5) | |
| High school | 27.6 (22.1–33.3) | 27.4 (19.9–34.9) | 25.5 (16.8–34.7) | 24.1 (12.7–35.8) | 27.0 (16.8–38.9) | |
| University | 40.3 (34.8–46.0) | 36.8 (29.3–44.3) | 32.8 (24.1–42.0) | 32.9 (21.5–44.7) | 31.5 (21.3–43.4) | 0.449 |
| Residence | ||||||
| In the parental home | 29.7(25.1–34.5) | 27.8 (21.9–34.1) | 28.8 (21.6–36.4) | 31.6 (23.9–40.6) | 28.9 (20.0–38.3) | |
| Away from the parental home | 70.3 (65.7–75.1) | 72.2 (66.3–78.5) | 71.2 (64.0–78.9) | 68.4 (60.7–77.4) | 71.7 (62.2–80.5) | 0.949 |
| Positive expectations about alcohol | ||||||
| Low | 29.7 (23.7–36.0) | 33.0 (25.1–41.0) | 34.2 (25.0–44.3) | 35.4 (25.3–46.4) | 31.6 (20.3–43.7) | |
| Medium | 38.0 (32.0–44.4) | 30.7 (22.9–38.8) | 31.7 (22.5–41.8) | 32.3 (22.2–43.4) | 30.4 (19.0–42.5) | |
| High | 32.3 (26.3–38.7) | 36.3 (28.5–44.4) | 34.2 (25.0–44.3) | 32.3 (22.2–43.4) | 38.0 (26.6–50.0) | 0.705 |
| Age of onset of alcohol use | ||||||
| After age 16 | 18.1 (12.5–24.1) | 16.8 (9.2–24.7) | 15.5 (6.9–25.5) | 16.4 (6.0–29.7) | 18.2 (7.8–30.3) | |
| Age 16 | 36.9 (31.2–42.8) | 41.0 (33.5–49.0) | 44.0 (35.3–54.0) | 50.7 (40.3–64.0) | 48.1 (37.7–60.1) | |
| Age 15 | 21.6 (15.9–27.5) | 20.2 (12.7–28.2) | 21.6 (12.9–1.6) | 23.9 (13.4–37.2) | 20.8 (10.4–32.8) | |
| Before age 15 | 23.4 (17.8–29.4) | 22.0 (14.4–30.0) | 19.0 (10.3–9.0) | 9.0 (0.0–22.3) | 13.0 (2.6–25.1) | 0.381 |
| Binge drinkinga | ||||||
| Never | 39.1 (34.0–44.7) | 43.2 (36.4–50.6) | 42.4 (34.5–51.7) | 46.9 (37.0–58.9) | 45.6 (35.6–56.5) | |
| Less than once a month | 25.3 (20.2–31.0) | 20.4 (13.6–27.8) | 21.6 (13.7–30.8) | 21.0 (11.1–33.0) | 21.1 (11.1–32.1) | |
| Monthly | 12.7 (7.5–18.3) | 14.6 (7.8–22.0) | 13.7 (5.7–22.9) | 17.3 (7.4–29.3) | 15.6 (5.6–26.5) | |
| More frequently | 22.9 (17.8–28.6) | 21.8 (15.0–29.2) | 22.3 (14.4–31.6) | 14.8 (4.9–26.8) | 17.8 (7.8–28.8) | 0.905 |
| AUDIT: Total (mean) | 7.8 (7.2–8.4) | 7.4 (6.6–8.2) | 7.3 (6.4–8.2) | 6.5 (5.4–7.6) | 7.1 (6.0–8.2) | 0.784 |
a Question 3 of the Alcohol Use Disorders Identification Test (AUDIT).