Table 1. Characteristics of female initial sample and follow-up samples.
| Percentage or mean (95%CI) | ||||||
|---|---|---|---|---|---|---|
| Initial (18–19 years old) n = 992 |
2-year follow-up (20–21 years old) n = 669 (67.4%) |
4 year follow-up (22–23 years old) n = 461 (46.5%) |
6 year follow-up (24–25 years old) n = 266 (26.8%) |
9 year follow-up (27–28 years old) n = 325 (26.8%) |
p-value | |
| Maternal educational level | ||||||
| Primary school | 41.8 (38.4–45.3) | 44.2 (40.1–48.4) | 43.1 (38.3–48.3) | 47.3 (41.3–54.1) | 45.7 (40.1–51.8) | |
| High school | 33.6 (30.2–37.1) | 30.5 (26.4–34.7) | 30.6 (25.8–35.8) | 26.5 (20.4–33.3) | 28.1 (22.5–34.2) | |
| University | 24.6 (21.2–28.1) | 25.3 (21.3–29.6) | 26.3 (21.4–31.4) | 26.1 (20.1–32.9) | 26.2 (20.7–32.4) | 0.642 |
| Residence | ||||||
| In parental home | 24.7 (22.1–27.5) | 22.9 (19.7–26.1) | 22.2 (18.5–26.0) | 22.1 (18.1–26.1) | 20.9 (16.5–25.1) | |
| Away from the parental home | 75.3 (72.6–78.0) | 77.1 (74.0–80.3) | 77.8 (74.1–81.6) | 77.9 (73.9–81.9) | 79.1 (74.9–83.5) | 0.720 |
| Positive expectations about alcohol | ||||||
| Low | 37.1 (33.4–40.9) | 37.5 (33.2–42.1) | 36.5 (31.4–42.0) | 36.5 (30.9–42.3) | 37.9 (31.7–44.3) | |
| Medium | 34.0 (30.3–37.8) | 32.6 (28.3–37.3) | 34.6 (29.4–40.1) | 35.4 (29.8–41.1) | 34.8 (28.6–41.2) | |
| High | 28.9 (25.2–32.7) | 29.9 (25.5–34.5) | 28.9(23.7–34.4) | 28.1 (22.5–33.8) | 27.2 (21.0–33.6) | 0.999 |
| Age of onset of alcohol use | ||||||
| After age 16 | 19.0 (16.5–21.8) | 17.9 (14.9–21.3) | 16.5 (13.0–20.5) | 16.7 (12.1–22.5) | 14.5 (10.5–19.2) | |
| Age 16 | 38.9 (35.6–42.2) | 38.1 (34.1–42.2) | 36.8 (32.0–41.7) | 40.1(33.6–46.8) | 36.6 (30.9–42.6) | |
| Age 15 | 25.6 (22.7–28.7) | 25.9 (22.3–29.6) | 26.5 (22.2–31.1) | 26.4 (20.8–32.7) | 28.3 (23.0–34.0) | |
| Before age 15 | 16.5 (14.0–19.7) | 18.1 (15.0–21.5) | 20.3 (16.4–24.5) | 16.7 (12.1–22.5) | 20.7 (16.0–25.9) | 0.438 |
| Binge drinkinga | ||||||
| Never | 61.2 (58.2–64.3) | 61.3 (57.7–65.1) | 59.0 (54.7–63.7) | 59.4 (53.8–65.5) | 60.0 (54.8–65.4) | |
| Less than once a month | 20.9 (17.8–23.9) | 20.9 (17.3–24.7) | 23.4 (19.1–28.1) | 22.2 (16.5–28.3) | 22.5 (17.2–27.9) | |
| Monthly | 9.8 (6.7–12.8) | 9.1 (5.5–12.9) | 9.1 (4.8–13.8) | 9.8 (4.1–15.9) | 9.8 (4.6–15.3) | |
| More frequently | 8.2 (5.1–11.2) | 8.7 (5.1–12.5) | 8.5 (4.1–13.2) | 8.6 (3.0–14.8) | 7.7 (2.5–13.1) | 0.999 |
| AUDIT: Total (mean) | 5.4 (5.2–5.7) | 5.6 (5.1–5.8) | 5.6 (5.2–6.0) | 5.6 (5.0–6.1) | 5.3 (4.9–5.8) | 0.884 |
a Question 3 of the Alcohol Use Disorders Identification Test (AUDIT).