Objective: The goal of this study was to examine the independent and joint associations between anxiety and depression symptoms with the risk of heart disease.
Methods: A total of 30,635 participants from the CARTaGENE community cohort study in Quebec who did not have heart diseases at baseline were included in the study. Baseline anxiety and depression symptoms were assessed using validated questionnaires. Survey data were linked with diagnostic codes from a public insurance database to examine incident heart disease during a 7-year follow-up period. Cox regression analyses were conducted comparing groups with high anxiety only, high depression only, comorbid anxiety and depression, and no/low symptoms of both on the risk of heart disease. Additional analyses examined anxiety and depression using continuous questionnaire symptom scores, data-driven comorbidity groups, and diagnostic codes. Covariates included sociodemographic characteristics, health behaviors, diabetes, and hypertension.
Results: In the main analyses, we found that, although depression without anxiety symptoms was associated with an increased risk of heart disease (hazard ratio = 1.35, 95% confidence interval = 1.04-1.74), there was no significant association for anxiety without depression symptoms (hazard ratio = 1.00, 95% confidence interval = 0.71-1.41). High anxiety assessed with diagnostic codes or by examining latent classes was, however, associated with a higher risk of heart disease.
Conclusions: The association between anxiety and incident heart disease may be accounted for by comorbid depression, particularly when anxiety and depression symptoms are assessed using self-report questionnaires. Differing methods of assessment and analysis, and adjustment for comorbid depression may explain differences in findings across different studies on anxiety and the risk of heart disease.