Risk of dementia associated with cardiometabolic abnormalities and depressive symptoms: a longitudinal cohort study using the English longitudinal study of ageing

Abstract

Objectives: Depression and cardiometabolic abnormalities are independently associated with a high risk of dementia. This study aimed to examine the association of comorbid depressive symptoms and cardiometabolic abnormalities with risk of dementia.

Methods: The sample comprised 4859 participants aged 50 or older without baseline dementia who took part in the English Longitudinal Study of Ageing (waves 2-7). Depressive symptoms were assessed using the Center for Epidemiologic Studies-Depression tool. Cardiometabolic abnormalities were defined as three or more cardiometabolic risk factors (inflammation, central obesity, raised triglycerides, low high-density lipoprotein [HDL] cholesterol, hypertension, and hyperglycaemia or diabetes). Participants were classified into four groups based on presence of depressive symptoms and cardiometabolic abnormalities. Results were analysed using the Cox proportional hazards regression adjusted for covariates.

Results: A total of 216 cases of incident dementia were reported over 10 years of follow-up. The group with high depressive symptoms only had an increased hazard of developing incident dementia during follow-up (HR = 2.68; 95%CI, 1.70-4.23), which was attenuated after adjustment for baseline cognition. No evidence was found for an association of overall cardiometabolic abnormalities with incident dementia; though hyperglycaemia, hypertension, and abdominal obesity with depressive symptoms had an unadjusted association with incident dementia. Only low-HDL cholesterol with depressive symptoms had an adjusted association with incident dementia (HR = 0.18; 95%CI, 0.04-0.75).

Conclusions: This work confirms depressive symptoms as a risk factor for incident dementia. However, low HDL-cholesterol with depressive symptoms may be protective against dementia, though more work is required to confirm this association.

Keywords: cardiometabolic risk factors; dementia; depression.

Figure 1

Participant flow chart. noDnoCM: no or low depressive symptoms and no cardiometabolic abnormalities group; DnoCM: high depressive symptoms only group; noDCM: cardiometabolic abnormalities only group; DCM: comorbid high depressive symptoms and cardiometabolic abnormalities group

Figure 2

Kaplan–Meier survival curves stratified by depression and cardiometabolic abnormalities groups. The survival curves display survival probabilities (cumulative survival probability) of individuals remaining disease free at any time after baseline. The survival time was the time‐to‐dementia, measured in months. noDnoCM: no or low depressive symptoms and no cardiometabolic abnormalities group; DnoCM: high depressive symptoms only group; noDCM: cardiometabolic abnormalities only group; DCM: comorbid high depressive symptoms and cardiometabolic abnormalities group