A 10-year observational study on the trends and determinants of smoking status.

Introduction: Most studies on motivation and intention to quit smoking have been conducted among adolescents and young adults but little is known regarding middle-aged subjects. We aimed to assess the trends and determinants of smoking status in a population-based cohort.

Method: Observational, prospective study with a first mean follow-up at 5.6 years and a second at 10.9 years. Data from 3999 participants (49.2% women, aged 35-75 years) living in Lausanne (Switzerland).

Results: Baseline prevalence of never, former and current smokers was 41.3, 34.3 and 24.3%, respectively. During the study period, more than 90% of never and former and almost 60% of current smokers at baseline retained their status after 10.9 years. Among 973 current smokers, 216 (22.2%) had quit for at least 5 years. Multivariable analysis showed increasing age to be positively associated with quitting (p-value for trend <0.001). Among 1373 former smokers, 149 (10.9%) had relapsed; increasing age (p-value for trend <0.001) was negatively associated and family history of lung disease was positively associated with relapse [OR and 95% CI: 1.53 (1.06-2.21)]. Among 1653 never smokers, 128 (7.7%) initiated smoking; Male gender [1.46 (1.01-2.12)] and living in coupled relationship [0.66 (0.45-0.97)] were associated with smoking initiation.

Conclusion: Most middle-aged never and former smokers did not change their status with time, while 22.2% of current smokers sustained quitting. This is encouraging and could be improved with adequate supportive methods. In comparison to available data, this study confirms the difficult task of identifying subjects at risk of a negative behavioral change.