Tobacco and alcohol co-use: Lifestyle and sociodemographic factors, and personality aspects as potential predictors in the "Seguimiento Universidad de Navarra" cohort

Tobacco and alcohol co-use are two major lifestyle modifiable risk factors. Understanding the determinants of both behaviors helps to develop interventions to prevent these exposures. However, previous studies have focused on predictors of individual tobacco or alcohol use. This study aims to explore the potential predictors of tobacco and alcohol co-use among Spanish university graduates from the "Seguimiento Universidad de Navarra" (SUN) cohort study. A total of 7175 participants who were co-users of tobacco and alcohol were selected for this cross-sectional analysis. Their mean age was 39.1 years (12.04 SD) and 57.3% were women. Univariate regression models were used to select the potential predictors of tobacco and alcohol co-use, and the areas under the ROC curves (AUC) were calculated. Multivariable logistic regression models were used to create a predictive model. Baseline potential predictors included sociodemographic factors, lifestyle habits, and perceived personality aspects. In the multivariable model, the main significant potential predictors of tobacco and alcohol co-use were driving under the influence of alcohol (odds ratio [OR] = 1.65 [1.43-1.90]), drinking 1-2 cups of coffee daily (OR = 1.50 [1.24-1.84]), and drinking three or more cups of coffee daily (OR = 1.61 [1.35-1.91]) when compared with the reference group. Conversely, those who were married (OR = 0.87 [0.75-0.99], ate at home 7 days a week (OR = 0.69 [0.60-0.80]), did more physical activity than recommended (OR = 1.18 [1.02-1.34]), or had a high perceived level of competitiveness (OR = 0.83 [0.72-0.95]) had a lower risk of co-use (AUC 0.61 [confidence interval 95% 0.59-0.63]), compared to the reference group. These results could be used by healthcare professionals, especially nurses, to effectively assess patients at higher risk of tobacco and alcohol co-use.