Depressive symptoms and incident cognitive impairment in cognitively well-functioning older men and women.

OBJECTIVES

To investigate whether the effect of depressive symptoms on the risk of cognitive decline and incident cognitive impairment (CI) in cognitively well-functioning older persons differed between men and women and whether sex differences in cerebrovascular factors might explain this.

DESIGN

Prospective cohort study.

SETTING

General community.

PARTICIPANTS

One thousand four hundred eighty-seven well-functioning Chinese older adults (Mini-Mental State Examination (MMSE) score > or =24) assessed at baseline for the presence of depressive symptoms (Geriatric Depression Scale score > or =5), and covariates (age, apolipoprotein E epsilon4, education, smoking, alcohol drinking, and vascular risk factors and diseases).

MAIN OUTCOME MEASURES

Incident CI and change in MMSE were assessed at 2-year follow-up.

RESULTS

In the whole sample, participants with depression showed significantly more incident CI than those without (5.7% vs 2.6%, P=.04; adjusted odds ratio (OR)=2.29, 95% confidence interval (CI)=1.05-5.00. Significantly higher OR was observed only in men (OR=4.75, 95% CI=1.22-18.5) and not for women (OR=1.29). There was a correspondingly greater rate of cognitive decline in participants with depressive symptoms that was observed to be marked only in men and not in women. The association was accentuated in subgroups with hypertension or vascular factors, but the sex differences in association were consistently observed.

CONCLUSION

The association between depressive symptoms and risk of cognitive decline was observed only in men and was not explained by sex differences in vascular factors. The comorbid presence of underlying cerebral vascular pathology or multi-infarct disease was possibly not a mediating factor but might amplify the process of cognitive decline.