The prediction of subjective wellness among the old-old: implications for the "fourth-age" conception.

Objectives: As the "fourth-age" conception suggests that the adaptability of psychosocial capabilities is disrupted at old-old age due to failures in maintaining balanced functions, this study examines the predictability of subjective wellness outcomes by factual dysfunction markers of health among old-old people across 12 years.

Method: Participants were self-respondents in a 3-wave survey that sampled the older (age 75-94) Jewish population in Israel. Wave 1 (N = 1,369, mean age = 83.5) preceded Wave 2 (N = 687, mean age = 85.4) by 4 years and Wave 3 (N = 164, mean age = 91.6) by 12 years.

Results: The dysfunction markers (comorbidity, medication consumption, doctor's visits, and difficulties in activities of daily living [ADL]) predicted subjective wellness by relating to an increase in depressive symptoms, as well as to a decrease in life evaluation and self-rated health, beyond adjustment for sociodemographics. However, in most cases, an interaction finding indicated that dysfunction markers were weaker predictors of age-related change in subjective wellness among older participants.

Discussion: At old-old age, the results point to reduced predictability of subjective wellness by factual dysfunction. This finding supports the fourth-age model. Still, researchers should consider an alternative interpretation, by which increasing independence between factual and subjective indicators is protective, rather than debilitating, among old-old people.