Summary: A new study finds that older adults with more pronounced depressive symptoms tend to have smaller overall brain volume and a 55% higher likelihood of having small vascular lesions in the brain, and those symptoms are associated with poorer episodic memory.
Source: AAN
Depressive symptoms in older adults are associated with memory deficits and structural brain changes, according to a study published online May 9, 2018, in Neurology. The research suggests that late-life depressive symptoms may coincide with markers of brain aging, including reduced brain volume and subclinical vascular lesions.
“Because depressive symptoms can be treated, it is possible that addressing depression could also help limit or reduce associated thinking and memory problems,” said study author Adina Zeki Al Hazzouri, PhD, MS, of the University of Miami Miller School of Medicine. “With up to one in four older adults experiencing depressive symptoms, understanding how depression relates to cognitive health is clinically important.”
The analysis drew on data from 1,111 stroke-free participants in the Northern Manhattan Study, with a mean age of 71. The cohort was predominantly Caribbean Hispanic. At baseline, participants completed MRI brain imaging, a standardized depression questionnaire, and cognitive testing that included measures of memory and other thinking skills. Cognitive testing was repeated after an average follow-up of five years.
Depressive symptoms were assessed using the Center for Epidemiological Studies–Depression Scale (CES-D). A CES-D score of 16 or higher (on a 0–60 scale) was used to indicate greater depressive symptoms and increased risk of clinical depression. At baseline, 22% of participants met or exceeded this threshold.
After adjusting for age, race/ethnicity, use of antidepressant medications, vascular risk factors, and other covariates, greater depressive symptoms were significantly associated with poorer episodic memory. On standardized testing, those with greater depressive symptoms scored approximately 0.21 standard deviations lower on episodic memory tasks compared with those with lower symptom levels. Episodic memory refers to the ability to recall specific events and personal experiences.
Neuroimaging analyses revealed that higher depressive symptoms were linked to smaller overall brain volume (measured as a reduced cerebral parenchymal fraction) and to higher odds of having silent subclinical brain infarcts—small vascular lesions often attributed to small vessel disease. Specifically, participants with greater depressive symptoms had about a 55% increased likelihood of silent brain infarcts. No significant associations were found between depressive symptoms and hippocampal volume, white matter hyperintensity volume, or measurable decline in cognitive performance over the five-year interval.
“Small subclinical vascular lesions reflect damage to the walls of small blood vessels in the brain,” Zeki Al Hazzouri explained. “Our findings are consistent with the idea that depressive symptoms and brain aging processes may occur together, and that depression could be linked to brain health through small vessel disease.”
The study provides important information about depression and cognition in an understudied population—older Hispanic adults—who may face elevated risks for dementia in later life. Because the cohort was largely Caribbean Hispanic, these results add valuable data about disparities in brain aging and mental health.
Limitations noted by the investigators include selection bias: participants had to be well enough to undergo MRI, so the sample may have been healthier than the general older population. In addition, the average follow-up of five years may not have been long enough to detect subtle or delayed cognitive decline associated with depressive symptoms and structural brain changes.
Funding: The study was supported by the National Institutes of Health, the American Heart Association, and the Evelyn F. McKnight Brain Institute.
Source: Renee Tessman – AAN
Publisher: Organized by NeuroscienceNews.com.
Image source: NeuroscienceNews.com image is in the public domain.
Original research: Abstract for “Greater depressive symptoms, cognition, and markers of brain aging: Northern Manhattan Study” by Adina Zeki Al Hazzouri et al., published in Neurology on May 9, 2018.
doi: 10.1212/WNL.0000000000005639
Greater depressive symptoms, cognition, and markers of brain aging: Northern Manhattan Study
Objective: The investigators examined whether higher levels of depressive symptoms were associated with specific cognitive abilities, with cognitive change over time, and with MRI markers of brain atrophy and subclinical cerebrovascular disease in a diverse sample of older adults.
Methods: Data came from the Northern Manhattan Study, a prospective cohort of mostly Caribbean Hispanic, stroke-free older adults. A total of 1,111 participants had baseline measures of depressive symptoms (CES-D), MRI markers, and cognitive performance. A CES-D score ≥16 was used to define greater depressive symptoms. Multivariable linear and logistic regression models adjusted for sociodemographic, behavioral, vascular risk factors, and antidepressive medication use were employed to evaluate associations.
Results: At baseline, 22% of participants had greater depressive symptoms. Higher depressive symptoms were significantly linked to worse baseline episodic memory (β = −0.21; 95% CI −0.33 to −0.10; p = 0.0003). Greater depressive symptoms were also associated with smaller cerebral parenchymal fraction (β = −0.56; 95% CI −1.05 to −0.07; p = 0.02) and increased odds of subclinical brain infarcts (OR = 1.55; 95% CI 1.00–2.42; p = 0.05). There were no significant associations with white matter hyperintensity volume, hippocampal volume, or cognitive change over an average follow-up of five years. Results remained consistent after accounting for selective attrition.
Conclusions: In this mostly Caribbean Hispanic, stroke-free sample of older adults, greater depressive symptoms were associated with poorer episodic memory, smaller overall brain volume, and higher prevalence of silent infarcts, suggesting a link between depressive symptoms and markers of brain aging.