Anxiety in Portugal: Associated Factors in Adult Population from 2011 to 2021

Background/Objectives: Anxiety disorders are the most prevalent mental illnesses worldwide and in Portugal, often resulting in chronicity and disability. The objective of this study is to evaluate the sociodemographic and health-related factors associated with anxiety in the Portuguese adult population. Methods: This study included participants aged 18 to 65 years from the nationwide, population-based EpiDoC cohort, who were followed from 2011 to 2021 (n = 2927). Anxiety was assessed using the Hospital Anxiety and Depression Scale (HADS). A mixed logistic regression analysis was performed using a prospective analytical approach. Two strategies were used to adjust the mixed models: (i) model with only complete observations (n = 1950) and (ii) model with imputation of the category “No” in missing self-reported diseases (n = 2554). Results: The proportion of anxiety symptoms decreased from 2011–2013 to 2021 (12.5% vs. 8.5%). Experienced anxiety symptoms were positively associated (OR > 1, p < 0.05) with being female; having a high school, 2nd and 3rd cycle (6–9 years of studies), or primary/no education; being unemployed; seeking the first job; and not working or being temporarily unable to work. Additionally, anxiety symptoms were positively associated (OR > 1, p < 0.05) with smoking daily, lack of physical exercise, and medication use. Digestive diseases, multimorbidity, and region were also positively associated (OR > 1, p < 0.05) with anxiety symptoms. Moreover, age was negatively associated (OR < 1, p < 0.05) with experiencing anxiety symptoms. Conclusions: Some determinants are modifiable and preventable through economic, social, and health policies. Measures to promote healthy lifestyles, like physical exercise, reduce substance abuse, prevent chronic diseases, increase employability, and increase schooling and health literacy, are necessary to reduce the anxiety rate in Portugal.