Higher burden of depression among older women: the effect of onset, persistence, and mortality over time.

Context: The prevalence of depression is disproportionately higher in older women than men, yet the reasons for this sex difference are not clear.

Objective: To determine whether the higher burden of depression among older women than men might be attributable to sex differences in the onset (ie, first or recurrent episodes) or persistence of depression and/or to differential mortality among those who are depressed.

Design: Prospective cohort study.

Setting: General community in greater New Haven, Connecticut, from March 23, 1998, to August 31, 2005.

Participants: A total of 754 persons, 70 years or older, who were evaluated at 18-month intervals for 72 months.

Main Outcome Measures: The 3 outcome states were depressed, nondepressed, and death, with scores of 20 or more and less than 20 on the Center for Epidemiological Studies Depression Scale denoting depressed and nondepressed, respectively. The association between sex and the likelihood of 6 possible transitions (namely, from nondepressed or depressed to nondepressed, depressed, or death) was evaluated over time.

Results: The prevalence of depression was substantially higher among women than men at each of the 5 time points (P < .001). In most cases, transitions between the nondepressed and depressed states were characterized by moderate to large absolute changes in depression scores (ie, > or = 10 points). Adjusting for other demographic characteristics, women had a higher likelihood of transitioning from nondepressed to depressed (odds ratio, 2.02; 95% confidence interval, 1.39-2.94) and a lower likelihood of transitioning from depressed to nondepressed (odds ratio, 0.27; 95% confidence interval, 0.13-0.56) or death (odds ratio, 0.24; 95% confidence interval, 0.09-0.60).

Conclusion: Among older persons, the higher burden of depression in women than men seems to be attributable to a greater susceptibility to depression and, once depressed, to more persistent depression and a lower probability of death.