Twenty-Year Depressive Trajectories Among Older Women

Context Despite the frequent occurrence of depressive symptoms among older adults, especially women, little is known about the long-term course of late-life depressive symptoms.\ud \ud Objective To characterize the natural course of depressive symptoms among older women (from the young old to the oldest old) followed up for almost 20 years.\ud \ud Design Using latent-class growth-curve analysis, we analyzed women enrolled in an ongoing prospective cohort study (1988 through 2009).\ud \ud Setting Clinic sites in Baltimore, Maryland; Minneapolis, Minnesota; the Monongahela Valley near Pittsburgh, Pennsylvania; and Portland, Oregon.\ud \ud Participants We studied 7240 community-dwelling women 65 years or older.\ud \ud Main Outcome Measure The Geriatric Depression Scale short form (score range, 0-15) was used to routinely assess depressive symptoms during the follow-up period.\ud \ud Results Among older women, we identified 4 latent classes during 20 years, with the predicted probabilities of group membership totaling 27.8% with minimal depressive symptoms, 54.0% with persistently low depressive symptoms, 14.8% with increasing depressive symptoms, and 3.4% with persistently high depressive symptoms. In an adjusted model for latent class membership, odds ratios (ORs) for belonging in the increasing depressive symptoms and persistently high depressive symptoms classes, respectively, compared with a group having minimal depressive symptoms were substantially and significantly (P < .05) elevated for the following variables: baseline smoking (ORs, 4.69 and 7.97), physical inactivity (ORs, 2.11 and 2.78), small social network (ORs, 3.24 and 6.75), physical impairment (ORs, 8.11 and 16.43), myocardial infarction (ORs, 2.09 and 2.41), diabetes mellitus (ORs, 2.98 and 3.03), and obesity (ORs, 1.86 and 2.90).\ud \ud Conclusions During 20 years, almost 20% of older women experienced persistently high depressive symptoms or increasing depressive symptoms. In addition, these women had more comorbidities, physical impairment, and negative lifestyle factors at baseline. These associations support the need for intervention and prevention strategies to reduce depressive symptoms into the oldest-old years.\ud \ud While evidence suggests that as many as 27% of community-dwelling older adults (≥65 years) experience depressive symptoms,1 little is known about the long-term course and heterogeneity of late-life depression. Given the projected expansion of the older populations and the health and economic costs of depression,2,3 greater understanding of the long-term course of depressive symptoms into the oldest-old years and the typologies that describe this long-term course will inform intervention and prevention strategies.\ud \ud Most prior investigations have assessed depressive symptoms at only one time point.4 However, while depression peaks in young adulthood, it also tends to occur at high and varying rates in late life.5 Because of the associations of depression with morbidity, poor health outcomes, and mortality,6- 10 a persistent increase in depressive symptoms over time may have major health implications. Few studies11- 16 have assessed trajectories of depressive symptoms in older participants, and these have been limited by short follow-up periods. In addition, because the oldest old (≥80 years) are the fastest growing age group in the United States and because a high incidence of depressive symptoms has been found among the oldest old,17 long-term investigation of depressive symptoms is needed in this age group.\ud \ud The primary objective of our study was to characterize the natural course of depressive symptoms among older women followed up for almost 20 years into their ninth and tenth decades of life. A secondary objective was to examine if lifestyle factors, functional impairment, and comorbidities known to be associated with late-life depression differentially predict more severe depressive symptom trajectories