Skip to main content

Table 2 Percentage of heavy drinking and frequency of binge drinking at one and six months follow-up by condition (WDYD intervention versus control): intention-to-treat analyses (multiple imputation) (N = 609) and completers-only analyses (n = 280) adjusted for clustering and covariates (i.e., gender and education level)

From: The effectiveness of a web-based brief alcohol intervention in reducing heavy drinking among adolescents aged 15–20 years with a low educational background: a two-arm parallel group cluster randomized controlled trial

   Intervention Control     
   n % n % OR 95% CI P NNT
Heavy drinking
1-month follow-up          
  Intention-to-treat 318 25.3 291 26.3 0.96 [0.84 to 1.10] 0.54 83
  Completers-only 130 34.6 150 37.3 0.91 [0.79 to 1.04] 0.18 37
6-month follow-up          
  Intention-to-treat 318 29.5 291 31.5 0.97 [0.84 to 1.11] 0.65 49
  Completers-only 130 30.8 150 34.7 0.91 [0.77 to 1.08] 0.28 26
Frequency of binge drinking
1-month follow-up          
  Intention-to-treat 318 43.3 291 47.7 0.92 [0.82 to 1.04] 0.18 23
  Completers-only 130 57.7 150 66.7 0.85 [0.73 to 0.98] 0.03 11
6-month follow-up          
  Intention-to-treat 318 55.3 291 57.5 0.95 [0.85 to 1.06] 0.35 49
  Completers-only 130 50.8 150 55.3 0.91 [0.80 to 1.03] 0.13 24
  1. Note. N number of participants OR odds ratios, CI confidence interval, P p-value, NNT number needed to treat.