Prevalence and Risk Factors of Cognitive Impairment and its Effect on Quality of Life: A Cross-Sectional Analysis of the TILDA Cohort

Objectives: Examine the prevalence of cognitive impairment within Wave 1 of the Irish Longitudinal Study on Aging (TILDA) cohort and its relationship with comorbidities and lifestyle factors. The effect of cognitive impairment on quality-of-life scores was also investigated. Methods: A secondary cross-sectional analysis of data from Wave 1 of the TILDA cohort was undertaken. Results: Prevalence of cognitive impairment ranged between 5.8% and 51.2%, depending on the instrument used (Mini-Mental State Examination [MMSE] and Montreal Cognitive Assessment [MoCA], respectively). Having hypertension (odds ratio [OR] 1.68; 95% confidence interval [CI] 1.36–2.08), being a past or current smoker (OR 1.25; 95% CI 1.01–1.55) and having low physical activity (OR 2.04; 95% CI 1.64–2.53) increased the odds of being classified as cognitively impaired (MMSE <25). Similarly, being obese (OR 1.31; 95% CI 1.17–1.47), having hypertension (OR 1.42; 95% CI 1.27–1.57), and having diabetes (OR 1.71; 95% CI 1.40–2.09) increased the odds of cognitive impairment (MoCA <26). High cholesterol was associated with a protective effect (OR 0.79; 95% CI 0.63–0.98) under MMSE <25 classification while, problematic alcohol behavior reduced the odds of being classified as cognitively impaired using MoCA <26 by 35% (OR 0.65; 95% CI 0.55–0.76). Depression was not associated with increased odds of cognitive decline. Lastly, mean quality of life (QoL) scores decreases as severity of cognitive impairment increases from normal to moderate cognitive impairment (P < 0.001). Conclusions: Several modifiable risk factors for cognitive decline were identified, including smoking, low physical activity, hypertension, diabetes, and obesity. Policies aimed at reducing the prevalence of these risk factors in the population might reduce the impact of cognitive decline on public health.