Table 2.
Absolute risk and average causal risk difference (ATE) of having a tattoo before age 25 years by sex and lifestyle factors. Inverse probability weight adjustment for population representativeness
| Individual analysis (%, 95% CI) |
Matched analysis i (%, 95% CI) |
|
|---|---|---|
| Female | 42.2 (38.6–45.8) | 37.6 (31.7–43.6) |
| Male | 32.3 (28.2–36.5) | 32.7 (24.6–40.7) |
| ATE (sex) | 9.9 (4.4–15.4) | 5.0 (− 7.0–19.1) |
| Ever smoker | 65.2 (59.1–71.3) | 59.8 (50.0–69.7) |
| Never smoker | 29.3 (26.4–32.2) | 29.6 (25.5–33.6) |
| ATE (smoking) | 35.9 (29.1–42.7) | 30.3 (19.6–41.0) |
| Alcohol | ||
| > 7 units per week | 43.1 (35.0–51.3) | 35.1 (24.7–45.4) |
| ≤ 7 units per week | 37.2 (34.2–40.2) | 35.9 (31.8–40.0) |
| ATE (alcohol) | 5.9 (− 2.8–14.7) | − 0.8 (− 12.0–10.4) |
| Physical activity ii | ||
| Active | 37.0 (31.9–42.0) | 33.2 (26.4–40.0) |
| Inactive | 38.8 (35.5–42.1) | 38.4 (33.9–42.9) |
| ATE (phys. activity) | − 1.9 (− 8.0–4.2) | − 5.2 (− 13.4–3.1) |
i)Among twin pairs discordant for exposure (e.g., sex or smoking)
ii)Active defined as more than 210 min of physical activity per week of moderate intensity