6 months after the end of programme implementation , students of intervention classes showed significantly lower rates for lifetime smoking ( adjusted OR = 0.63 ; 95 % CI 0.41 to 0.96 ; p = 0.026 ) and incidence of smoking ( adjusted OR = 0.66 ; 95 % CI 0.43 to 1.00 ; p = 0.047 ) , a higher increase of smoking-related knowledge ( adjusted = 9.38 ; 95 % CI 6.73 to 12.04 ; p < 0.001 ) and a greater change in attitudes towards a more critical perception of risks and disadvantages of smoking ( adjusted = 0.10 ; 95 % CI 0.03 to 0.16 ; p = 0.002 ) .