The effect of anxiety on all-cause dementia: A longitudinal analysis from the Hunter Community Study

Background: Anxiety is common, however, the effect of chronicity of anxiety on dementia has not been explored. This study aims to assess the longitudinal relationship between chronic versus resolved versus new onset anxiety, and all-cause dementia risk. Methods: A total of 2132 participants with mean age 76 years from the Hunter Community Study were recruited. Anxiety was measured using Kessler Psychological Distress Scale (K10). Dementia was defined as per International Classification of Disease—10 codes. The Fine–Gray subdistribution hazard model was computed to assess dementia risk, while adjusting for the competing risk of death. Results: Chronic anxiety and new onset anxiety at follow-up were associated with all-cause dementia risk (HR 2.80, 95% CI 1.35–5.72 and HR 3.20, 95% CI 1.40–7.45 respectively) with an average time to dementia diagnosis of 10 years (SD = 1.7) whereas resolved anxiety was not. In subgroup analyses, these results were driven particularly by chronic and new anxiety among participants below the age of 70 years (HR 4.58, 95% CI 01.12–18.81 and HR 7.21, 95%CI 1.86–28.02 respectively). Sensitivity analyses imputing missing data and addressing reverse causation gave very similar results. Conclusion: Chronic and new anxiety were associated with increased risk of all-cause dementia, and this association was significant in those 70 years and younger. However, the resolved anxiety at follow-up reduced the risk, similar to that of the non-exposed group. These results suggest that timely management of anxiety may be a viable strategy in reducing the risk of dementia.