Study Suggests Depression, Cognitive Impairment Negatively Impact Quality of Life Scores Among Older Adults

The combined effects of depressive symptoms and probable mild cognitive impairment (MCI) are associated with the worst-ranked outcomes for older adults’ quality of life, research suggests.

Depression and early stages of cognitive impairment (MCI) have been studied with regard to their associations with one another. While a causal link has not been established between the two, a research study led by Yan Liang, PhD, and Yinghua Yang, PhD, sought to assess their relationship more closely.

Liang and colleagues organized this cross-sectional study to analyze the combined effects of both depressive symptoms and cognitive impairment on what is described as health-related quality of life (HRQoL), specifically as it relates to older adults living in Chinese communities within Shanghai.

"This study focused on the subgroups with cognitive impairment and depressive symptoms in order to explore the more vulnerable groups and thus target preventive efforts on those most in need of them,” they wrote.

Research and Methods

The investigators used a cross-sectional study for their research, recruiting 2525 older adults ≥60 years old, dwelling in communities in Shanghai by the year 2019. They separated the older adult community-dwellers into 4 distinct categories for the purposes of the research:

• No depressive symptoms with no dementia
• No depressive symptoms with probable mild cognitive impairment (MCI)
• Depressive symptoms with no dementia
• Depressive symptoms with MCI

To calculate the participants’ HRQol, the investigators used the 36-Item Short-Form Health Survey (SF-36). The SF-36 uses a 0 - 100 ranking to evaluate bodily pain, physical functioning, role physical, general health, social functioning, vitality, role emotional, and general mental health.

The AD8 was used to assess evidence of cognitive impairment, using an answering system (yes is 1, no is 0) for 8 items with questions for participants to rate changes in memory, problem-solving, and daily activities. Those surveyed were then categorized as having dementia when they achieved a ≥2 cutoff score. The investigators used the Geriatric Depression Scale (GDS) to assess depressive symptoms in study participants, with 30 questions for the assessment in total.

They calculated overall HRQoL through the data collected from the AD8 and GDS analyses. The investigators determined a ranking system in which the data could be classified:

• Ad8 score ≥2 are classified as probably having MCI
• Ad8 score ≥2 and GDS score <11 are non-depressed with probable MCI
• Ad8 score <2 and GDS score ≥11 are depressed without dementia
• Ad8 score ≥2 and GDS score ≥11 are depressed with probable MCI
• Ad8 score <2 and GDS score <11 are not depressed and without dementia

Study Results

The investigators analyzed characteristics of participants and used linear regression analysis to determine factors associated with HRQoL. They found that the participants without depression and without dementia, unsurprisingly, scored the highest in all domains of HRQoL. This group was then followed by those without depression but with probable MCI, and then by those with depression but without dementia.

The researchers describe HRQoL as being made up of 2 elements: the physical component score (PCS) and the mental component score (MCS). They found that the participants who had depression along with probable MCI were the oldest, maintained the highest ADL and IADL disability levels, and maintained the lowest PCS and MCS.

Additionally, they found that participants with probable MCI—with or without depression—were more likely in their research to have reported a chronic disease. The major finding of the study was that both activities of daily living (ADL) and instrumental activities of daily living (IADL) were found to be mediating roles in the observed relationship between depression, cognitive impairment, and PCS.

“The indirect effect of ADL disability accounted for 32.86% of the total effect of depression with probable MCI on PCS and for 24.71% of the total effect of depression without MCI on PCS,” they wrote. “The indirect effect of IADL disability accounted for 30.94% of the total effect of no depression with probable MCI on PCS, accounting for 23.88% of the total effect of depression with probable MCI on PCS and for 21.10% of the total effect of depression without dementia on PCS.”

The investigators also added that improving HRQoL outcomes in aging adult populations may be more effectively improved with this research being used to detect early and adequately manage dementia, depression, and related disabilities.

This study, “Effects of cognitive impairment and depressive symptoms on health-related quality of life in community-dwelling older adults: The mediating role of disability in the activities of daily living and the instrumental activities of daily living,” was published on Wiley Online Library.