Objective:
More than 25% of smokers in Japan want to quit smoking, but half of them reportedly fail to do so even if they receive medical treatment for nicotine dependence. This study assessed the factors affecting the maintenance of smoking cessation.

Methods:
This retrospective cohort study was conducted using health examination and administrative claim data from 2012 to 2014, extracted from a database containing information on the insurance of beneficiaries employed in medium- and small-sized Japanese companies. The study included subjects who quit smoking. Logistic regression analysis was used to assess factors related to the smoking status after the subjects quit smoking, which included sex, age, income, occupation, and medical treatment for nicotine dependence.

Results:
Smoking prevalence among subjects was 37.1% in 2012, and 5.1% of them quit smoking in 2013. The percentage of smokers who quit smoking with medical treatment was 8.5%, mainly with varenicline. Data relating to smoking status in 2014 was available for 4,034 subjects, and 69.6% maintained smoking cessation. Logistic regression analysis showed that females and older individuals could significantly maintain smoking cessation. Treatment with varenicline was also significant: OR: 1.50 (95% CI, 1.14–1.96).

Conclusions:
Medical treatment for nicotine dependence using varenicline could maintain smoking cessation significantly, although it is reported that half the smokers who were treated started to smoke again. It is difficult for smokers to maintain smoking cessation and they require an effective support system. The difference between this treatment and other methods of smoking cessation could be attributed to the medication, as well as to the regular support provided by doctors and nurses. We need to consider the post-treatment support system in order to further improve the maintenance of smoking cessation.