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.