Multimorbidity Tied to Neurodegeneration and Vascular Pathology in Older Adults – Renal and Urology News

Multimorbidity among older adults is associated with accelerated structural brain changes affecting neurodegeneration and vascular pathology. These are the findings of a population-based cohort study published in the journal Alzheimer’s & Dementia.

Multiple chronic conditions, such as atrial fibrillation, diabetes, and pulmonary diseases have been associated with changes to the structure and function of the brain. However, many patients who are affected by a chronic condition have multiple comorbidities.

To evaluate the effect of multimorbidity on structural brain changes, researchers sourced data for this study from the magnetic resonance imaging (MRI) substudy of the Swedish National study on Aging and Care in Kungsholmen (SNAC-K MRI). Individuals (N=390; 57.7% women; mean age, 70.8) without dementia, disability, or institutionalization were recruited for this ongoing study starting in 2001. The study population comprised 27.6% apolipoprotein E (APOE) e4 carriers and 40.8% attended university.

Participants underwent MRI at baseline and at 3- and/or 6-year follow-ups.

In this study, changes in total brain, ventricular, hippocampal, and white matter hyperintensities (WMHs) volumes were evaluated on the basis of:

Multimorbidity: Co-occurrence of 2 or more chronic conditions

Mild multimorbidity: Co-occurrence of 2 or more chronic conditions affecting 1 or more body systems

Complex multimorbidity: Co-occurrence of 3 or more chronic conditions affecting 3 or more body systems

The most common chronic diseases included:

• hypertension (66.2%),
• dyslipidemia (56.4%),
• chronic kidney disease (26.7%),
• osteoarthrosis (13.6%), and
• obesity (12.6%).

The most affected systems were:

• cardiocirculatory (70.8%),
• endocrine or metabolism (69.2%),
• genitourinary (29.7%), and
• musculoskeletal (29.2%) systems.

The study participants had complex multimorbidity (n=200), mild multimorbidity (n=106), and no multimorbidity (n=84). Patients with multimorbidity were older, more were women, and they had lower levels of education than individuals without multimorbidity.

During a mean follow-up of 5.9 years, 12 individuals developed dementia. The dementia cohort had complex multimorbidity (n=8), mild multimorbidity (n=3), and no multimorbidity (n=1) at baseline.

Incident dementia was associated with a:

• nonsignificant, more rapid reduction in total brain tissue volume (TBTV; b*time, -0.15),
• accumulation of WMH (b*time, 0.35),
• hippocampal volume shrinkage (b*time, -0.14), and
• ventricular volume enlargement (b*time, 0.09).

Compared with the group without multimorbidity, those with multimorbidity had:

• significant reductions in TBTV (b, -0.33; 95% CI, -0.51 to -0.14),
• enlargement in ventricular volume (b, 0.27; 95% CI, 0.03 to 0.51),
• more rapid reduction in TBTV (b*time, -0.03; 95% CI, -0.05 to -0.01),
• accumulation of WMH (b*time, 0.03; 95% CI, 0.01-0.06),
• hippocampal volume shrinkage (b*time, -0.04; 95% CI, -0.07 to -0.01), and
• ventricular volume enlargement (b*time, 0.02; 95% CI, 0.01-0.04).

The number of chronic diseases at baseline was found to affect changes to TBTV and hippocampal volume and interactions with time were observed for ventricular and WMH volume changes.

This study may be limited as the participants were relatively healthy and fit with a high socioeconomic status.

“In a sample of older adults without dementia, a high disease burden, especially when multiple body systems are affected, accelerates the occurrence of mixed brain pathological changes, encompassing neurodegeneration and vascular pathology,” the researchers concluded.

This article originally appeared on Neurology Advisor