Assessing the real-world impact of a low nicotine product standard for smoked tobacco in New Zealand - A low nicotine product standard for cigarettes and other combusted tobacco products has been proposed as a cornerstone of the FDA’s Comprehensive Plan for Tobacco and Nicotine Regulation in the United States (US). This proposed standard is based largely on randomized clinical trials demonstrating that when people switch to very low nicotine content (VLNC) cigarettes, cigarettes per day, dependence and biomarkers of smoke exposure decrease and quit attempts and cessation increase. Yet, these trials have important limitations. Notably, they limit the duration of exposure to VLNC cigarettes; cannot recreate the complex context of real-world product standards; are characterized by the use of non-study, normal nicotine cigarettes; and generally focus on samples of convenience. The Smokefree 2025 Action Plan outlines a strategy to reduce smoking prevalence to less than 5%. A major component of the initiative is to mandate a low nicotine product standard for all smoked tobacco. Our primary research objective is to assess impact of a mandated reduction of nicotine in all smoked tobacco products. We propose to conduct a longitudinal, mixed methods cohort study of adults who smoke daily or nearly daily (N=1500), using online surveys, biomarkers of exposure, physiological assessments, qualitative interviews, and medical records to assess changes in smoking behavior, health and well-being. We will follow the cohort for 3.5 years (1.5 years before and 1 year after implementation of a low nicotine product standard). We will also explore potential differences by explicitly sampling individuals with self-reported anxiety and depression, adults with low educational attainment, and heavy alcohol and/or cannabis use. We will also enroll people who smoke but do not have these characteristics. The primary outcome for Aim 1 is abstinence from smoked tobacco (self-reported and biochemically-verified) at 52 weeks after policy implementation. The primary outcome for Aim 2 is Health-Related Quality of Life ratings at 52 weeks after policy implementation. Aim 3 will explore potential differences in response to a low nicotine products standard. As a team, we have complementary areas of expertise (e.g., behavioral pharmacology, public health and medicine, biostatistics, epidemiology, qualitative and mixed methods) to ensure the successful completion of the current proposal.