Dietary Iron Intake and Mental and Behavioral Disorders Due to Use of Tobacco: A UK Biobank Study

Background: Over 1 billion smokers worldwide, one-third of whom have mental and behavioral disorders, exist. However, factors influencing mental and behavioral disorders due to the use of tobacco remain largely unexplored. This study aims to investigate the relationship between dietary iron intake and mental and behavioral disorders due to the use of tobacco. Methods: Using large population cohort data from the UK Biobank (500,000 participants at 22 assessment centers between 2006 and 2010), we employed logistic and Cox regression analyses to explore both cross-sectional and longitudinal associations between dietary iron intake and mental and behavioral disorders due to the use of tobacco. Additionally, we assessed the nonlinear relationship between dietary iron intake and these disorders using restricted cubic spline plots. Results: Logistic regression analysis indicated that dietary iron intake was negatively associated with mental and behavioral disorders due to the use of tobacco. The Cox regression results supported a protective effect of increased dietary iron intake against these disorders. Stratified and sensitivity analyses were consistent with the primary findings. Restricted cubic spline plots revealed a nonlinear relationship between dietary iron intake and mental and behavioral disorders due to the use of tobacco. In the total sample, as well as in both age groups and the male subgroup, the risk reduction rate initially accelerated before slowing down. In contrast, the risk reduction rate in the female group declined rapidly at first and then leveled off. Conclusions: This study demonstrates that dietary iron intake has a protective effect against mental and behavioral disorders due to the use of tobacco, revealing a nonlinear association between these two traits. These findings provide important insights for the profilaxy and treatment of mental and behavioral disorders due to the use of tobacco in the future.