Changes in concentrations of tobacco specific nitrosamines in saliva in the general population of Barcelona before and after implementation of tobacco control legislation

CONTEXT: This study evaluated changes in salivary tobacco-specific nitrosamines (TSNAs) in smokers and non-smokers before and after Spain's smoke-free legislation. METHODS: We conducted a longitudinal study of 272 adults in Barcelona, surveyed in 2004-2005 and 2013-2014, spanning the 2006 legislation and its 2011 extension. Saliva samples were analyzed for NNN, NNK, and NNAL, and geometric means with 95% confidence intervals were calculated. Data were stratified by sociodemographics, smoking status, smoking behavior, and anthropometrics. Linear mixed-effects models assessed adjusted percentage changes in TSNA concentrations. RESULTS: At baseline, overall TSNA concentrations were 1.5 [1.2-1.8] pg/mL for NNN, 1.4 [1.3-1.5] pg/mL for NNK, and 0.5 [0.5-0.6] pg/mL for NNAL. Among baseline smokers who quit, TSNAs decreased by -90.5% (NNN), -48.7% (NNK), and -86.2% (NNAL). Continuing smokers showed a 149.8% increase in NNN, while non-smokers showed no significant change. CONCLUSIONS: Concentrations of salivary TSNAs declined in those who quit smoking but increased for continuing smokers. Monitoring TSNAs in saliva is useful for assessing legislative impact.