Loneliness as a risk factor for dementia and its mediators: A longitudinal cohort analysis of UK Biobank data

Abstract

Background and objectives

Growing evidence suggests that the feeling of loneliness correlates positively with the incidence of dementia, motivating our study of their longitudinal association. Additionally, we sought potential mediators of the association, following the hypotheses that lonely individuals are prone to greater stress and follow less healthy lifestyles, therefore are at greater risk of developping dementia.

Methods

Using longitudinal cohort data from the UK Biobank, we conducted a logistic regression analysis with loneliness as exposure and dementia diagnosis as outcome, and progressively adjusted for putative confounders. In addition, we investigated through mediation models the respective contributions of physiological and behavioural factors to the association between loneliness and dementia diagnosis.

Results

The logistic regression models illustrated a significant positive association between loneliness and a subsequent dementia diagnosis, overall indicating a higher odds of developing dementia in the lonely population (Adjusted Odds Ratio (AOR) = 1.39; 95 % (Confidence Interval) CI 1.24 – 1.56, P < 0.001). The mediation models highlighted that there was very little evidence of mediation by hypertension and unhealthy behaviours, respectively explaining 1 % and 2 % of the effect of loneliness on dementia risk. No indication of mediation was seen between baseline CRP-levels and all-cause dementia. Every mediation model described a positive correlation between loneliness and each potential mediating factor, illustrating the widespread negative impact of loneliness on health.

Conclusion

Our findings confirm the association between loneliness and risk of dementia. They show minimal mediation by hypertension and unhealthy behaviours, highlighting the need for investigation into other potential mediators as targets for modification.