Smoking initiation among Israeli adolescents: a 24-year time-to-event analysis

Introduction: Preventing smoking initiation will protect future generations from smoking-attributable death and disease. This study examines the correlates and patterns of initiation among Israeli youth using time-to-event analysis and other methods.

Methods: Twenty-four consecutive representative samples (1986-2009) of new military recruits (N=50,254) were analyzed. Cox regression and Kaplan-Meier analysis were used to identify factors associated with smoking initiation, and logistic regression was used to identify factors associated with smoking status.

Results: The most hazardous age for smoking initiation was seventeen, subsequent to the mean age of smoking initiation (males: 15.7, females: 16.0). Age of initiation and age of greatest hazard for initiation declined among recruits between the years 1986 and 2009. Earlier smoking initiation among boys and girls was significantly associated with low education levels (<12years) (males: HR=2.98, CI: [2.79, 3.18]; females: HR=3.35, CI: [2.96, 3.80]), low paternal education levels, Russian birthplace, and religion. Earlier initiation in boys was associated with high fitness levels and low/medium socio-economic status. Earlier initiation in girls was associated with being Western-born and ever-use of contraception.

Conclusions: Smoking initiation among Israeli youth recruited to the armed forces is associated with individual and family characteristics, particularly low education levels. Time-to-event analysis complements traditional means of understanding smoking initiation by identifying ages at which initiation hazard is high.