Effectiveness of smoking-cessation intervention in all of the smokers at a worksite in Japan.

In Japan, the prevalence of smoking among males and females was 56.1% and 14.2%, respectively, in 1997. Male smoking prevalence was exceedingly high as compared to those in other industrialized countries. We conducted a randomized controlled intervention study on smoking cessation for all smokers in a worksite regardless of their willingness to quit smoking. All of the male smokers in a radiator manufacturing factory (n=263) were randomly allocated to an intervention group (n=132) or a control group (n=131). Subjects in the intervention group received individual counseling by a doctor, and those who signed a Smoking Cessation Declaration underwent a five-month intervention. Subjects in the control group received equivalent delayed intervention for four months. The cessation rate after the original intervention was 12.9% (17/132) and 3.1% (4/131) in the intervention and control groups, respectively (p=0.003). Among those who once succeeded in quitting, 48.6% (18/37) maintained cessation at the long-term survey. Overall, the cessation rate was 8.4% (22/263) and the prevalence of smoking among males significantly decreased from 62.9 to 56.7% (p=0.038). As a conclusion, intervention in all smokers at a worksite regardless of their willingness to quit is effective and impacts the overall smoking rate.