Older age at smoking initiation predicts successful cessation in adults who smoke: A prospective study

Abstract

Objectives

We investigated the association between age at smoking initiation (ASI) and cigarette consumption, nicotine dependence, and smoking abstinence.

Methods

Data were drawn from 11 community-based, pragmatic randomized controlled trials nested within Hong Kong's annual ‘Quit to Win’ Contest, conducted from 2010 to 2021. Participants (n = 11,948) were people aged ≥ 18 years who smoked cigarettes daily. ASI was measured at baseline. Biochemically-validated and self-reported 7-day point-prevalence abstinence was assessed 6 months from baseline. Binary and multinomial logistic regressions estimated odds ratios of heavy cigarette consumption (cigarettes per day > 30), high nicotine dependence (Heaviness of Smoking Index > 4), and smoking abstinence for ASI.

Results

Of participants, 19.7 % were female, 54.8 % aged ≥ 40 years, and 87.3 % had secondary or higher education. Being female and higher educated was associated with later smoking initiation (all p < 0.001). As ASI increased from ≤ 14 to ≥ 23 years, the proportion of heavy cigarette consumption (6.2 % to 3.0 %, OR 0.87; 95 % CI 0.83–0.90) and high nicotine dependence (11.3 % to 5.3 %, OR 0.87; 95 % CI 0.83–0.90) reduced, while 6-month validated (4.7 % to 8.2 %, OR 1.05; 95 % CI 1.02–1.07) and self-reported abstinence (10.8 % to 18.1 %, OR 1.05; 95 % CI 1.03–1.05) increased.

Conclusions

Older age at smoking initiation was associated with lower cigarette consumption and higher nicotine dependence and predicted higher validated and self-reported abstinence. Implementing more stringent measures to prevent or delay smoking initiation could reduce tobacco use and improve cessation outcomes.