Food Insecurity as a Driver of Nicotine Exposure in Smokers? Evidence from NHANES 2015–2018

Background: Tobacco use and food insecurity (FI) often co-occur and may influence each other bidirectionally. While cross-sectional studies primarily focus on tobacco use's impact on FI, they typically rely on self-reported measures of tobacco use. This study aimed to investigate the effects of food insecurity on cotinine concentrations, a biomarker of nicotine exposure, and evaluate mediating and moderating factors. Methods: Data from the 2015–2018 National Health and Nutrition Examination Survey (NHANES) were analyzed for 2,843 adult smokers. Cotinine was log-transformed and modeled using generalized linear models, adjusted for socio-demographic covariates, body mass index (BMI), and depression score. Casual mediation analysis and structural equation modeling assessed mediation and moderation effects, with interaction terms between FI and covariates to test for moderation. Results: Each unit increase in FI severity was linked to a 33.6% rise in cotinine concentrations, controlling for covariates. Depression partially mediated this relationship, while college graduation moderated it. Among females, but not males, BMI mediated and depression moderated the association. In a subset of participants, smoking frequency also moderated the link, with FI weakening the relationship between smoking frequency and cotinine levels. Conclusions: FI may be an independent risk factor for higher cotinine concentrations, separate from smoking behavior and depression. These findings suggest that addressing FI could enhance tobacco cessation efforts. Future research should explore how FI influences nicotine metabolism and smoking patterns.