Loneliness is Independently Associated With Functioning in the Oldest Old: A Cross-Sectional Study Using Data From the Survey of Health, Ageing and Retirement in Europe.

Importance: Functionality is crucial for older adults' autonomy, and loneliness has emerged as a potential risk factor for chronic diseases. However, its role in functional limitations remains unclear.

Objective: The objective of this study was to analyze the association between loneliness and limitations in 1 or more basic activities of daily living (BADL) and instrumental activities of daily living (IADL) in individuals who were 80 years old or older.

Design: This was a cross-sectional study using data from wave 8 of the Survey of Health, Ageing and Retirement in Europe.

Setting: The study was conducted in 26 European countries.

Participants: Participants were 7434 community-dwelling adults who were 80 years old or older.

Exposure: Loneliness was assessed using the Three-Item Loneliness Scale, covering companionship, exclusion, and isolation.

Main outcome and measures: Functional limitations were defined as difficulty in 1 or more BADL (dressing, walking, bathing, eating, bed transfer, toileting), IADL (map use, preparing a hot meal, shopping, phone use, medication management, housework, finances, transportation, laundry), or in both types of activities (BADL and IADL). Sociodemographic and health-related variables were considered. Logistic regression and multivariate analyses were applied, using the odds ratio (OR) as the effect measure.

Results: The mean age was 84.4 (SD = 3.8) years; 58.2% of participants were women, and 52.5% had a low educational level. Loneliness affected 56% of participants, and 66% reported limitations in BADL/IADL. Loneliness was significantly associated with functional limitation in BADL/IADL in both univariate (OR = 2.18 [95% CI = 1.98-2.39]) and multivariate (OR = 1.50 [95% CI = 1.34-1.67]) models, even after adjustment for covariates, with an area under the receiver operating characteristic curve of 76%.

Conclusions: Loneliness is significantly and independently associated with limitations in BADL/IADL among the oldest-old.

Relevance: These findings highlight the importance of assessing psychosocial factors, such as loneliness, when evaluating functional health in the oldest-old.