Social Frailty Has a Stronger Impact on the Onset of Depressive Symptoms than Physical Frailty or Cognitive Impairment: A 4-Year Follow-up Longitudinal Cohort Study

Objectives: To examine the association between each type of frailty status and the incidence rate of depressive symptoms among community-dwelling older adults.

Design: Prospective cohort study.

Setting: General communities in Japan.

Participants: Participants comprised 3538 older Japanese adults.

Measurements: We assessed our participants in terms of frailty status (physical frailty, cognitive impairment, and social frailty), depressive symptoms (geriatric depression scale ≥6), and other covariates, and excluded those who showed evidence of depression. Then, after a 4-year interval, we again assessed the participants for depressive symptoms. Physical frailty was defined by the Fried criteria, showing 1 or more of these were physical frailty. To screen for cognitive impairment, receiving a score below an age-education adjusted reference threshold in 1 or more tests was cognitive impairment. Finally, social frailty was defined using 5 questions, and those who answered positively to 1 or more of these were considered to have social frailty.

Results: After multiple imputations, the incidence rate of depressive symptoms after 4 years of follow-up was 7.2%. The incidence rates of depressive symptoms for each frailty status were as follows: 9.6% for physical frailty vs 4.6% without, 9.3% for cognitive impairment vs 6.5% without, and 12.0% for social frailty vs 5.1% without. Finally, through the application of multivariable logistic regression analysis, the incidence of depressive symptoms was found to have a significant association with social frailty (odds ratio 1.55; 95% confidence interval 1.10-2.20) but not with physical frailty or cognitive impairment.

Conclusions: This study revealed that social frailty, in comparison with physical frailty and cognitive impairment, is more strongly associated with incidences of depressive symptoms among elderly.