The bidirectional relationship between depressive symptoms and functional limitations among centenarian survivors in their 80s: Testing bivariate latent change score models.

OBJECTIVES: The purpose of the study was to examine a bivariate latent change score model of depressive symptoms and functional limitations (activities of daily living) among centenarian or near-centenarian survivors over four waves using the Health and Retirement Study.

METHOD: Four hundred and sixty participants who eventually survived to age 98 or older were included by calculating their death age. Data from the time when the participants were in their 80s were analyzed. The mean age at baseline (1994) was 85.5 years. The observation interval was 2 years, from 1994 to 2000. Including age, gender, and education as a covariate, eight different models were conducted to examine the bivariate effects among depressive symptoms and functional limitations.

RESULTS: Of the eight models, the bivariate model of depressive symptoms predicting change in functional limitations fitted the data best. The parameter estimates of the final model indicated significant predictive pathways from depressive symptoms to subsequent changes in depressive symptoms and functional limitations.

CONCLUSION: This study tested the bidirectional relationship between depressive symptoms and functional limitations among centenarian survivors in their 80s, which uncovered that depressive symptoms is a dominant variable among the two constructs. Our findings add to a lacking number of longitudinal studies with oldest old adults.