Table 5

Results of the hierarchical logistic regression analysis

VariablesStep 1Step 2Step 3Step 4
OR (95% CI)OR (95% CI)OR (95% CI)OR (95% CI)
Demographic characteristics
 Age1.01 (0.81 to 1.26)1.01 (0.81 to 1.27)0.96 (0.76 to 1.21)0.97 (0.76 to 1.22)
 Sex1.38 (0.96 to 2.01)1.23 (0.84 to 1.79)1.47 (0.98 to 2.21)1.49 (0.99 to 2.24)
 Grade1.01 (0.69 to 1.46)1.00 (0.68 to 1.47)0.85 (0.57 to 1.28)0.86 (0.57 to 1.30)
 Father’s education1.19 (0.77 to 1.83)1.11 (0.71 to 1.72)1.09 (0.69 to 1.75)1.07 (0.67 to 1.72)
 Mother’s education0.90 (0.59 to 1.37)0.90 (0.58 to 1.38)0.89 (0.56 to 1.41)0.90 (0.57 to 1.43)
 Stress about grades1.08 (0.73 to 1.60)1.11 (0.74 to 1.66)0.98 (0.64 to 1.51)0.98 (0.64 to 1.51)
 Parents’ health status0.86 (0.46 to 1.61)0.90 (0.48 to 1.71)1.03 (0.53 to 2.00)0.99 (0.51 to 1.95)
 Parents’ economic status0.96 (0.61 to 1.52)0.96 (0.60 to 1.53)0.96 (0.58 to 1.57)0.96 (0.58 to 1.59)
 Pre-education of medicine0.82 (0.58 to 1.18)0.92 (0.64 to 1.33)0.89 (0.60 to 1.32)0.89 (0.60 to 1.32)
Perceived health threat*
 Susceptibility0.73 (0.50 to 1.06)0.62† (0.41 to 0.94)0.62† (0.41 to  0.94)
 Severity0.44† (0.29 to 0.67)0.41† (0.26 to 0.64)0.40† (0.25 to 0.62)
Likelihood of action‡
 Benefits
4.43† (2.77 to 7.09)4.32† (2.69 to 6.92)
 Harms
1.86† (1.16 to 2.99)1.78† (1.10 to 2.86)
Cues to act§ 
 Media1.36 (0.91 to 2.05)
 Recommendations from family members or friends1.22 (0.68 to 2.17)
Model summary
Na R20.015†0.070†0.195†0.202†
Δ R20.055†0.125†0.007†
  • *Perceptions of susceptibility and that the health threat of caffeinated drinks is serious.

  • †Statistically significant.

  • ‡Perceptions of the expected benefits or harms of using highly caffeinated energy drinks.

  • §The effect of suggestions from media or recommendations from family members or friends on motivation to consume highly caffeinated energy drinks.

  • Na, Nagelkerke.