Association of Social Support with Mild Cognitive Impairment and Dementia among Older Women: The Women's Health Initiative Memory Study

Background: Social support may be a modifiable risk factor for cognitive impairment. However, few long-term, large prospective studies have examined associations of various forms of social support with incident mild cognitive impairment (MCI) and dementia. Objective: To examine associations of perceived social support with incident MCI and dementia among community-dwelling older women. Methods: This prospective cohort study included 6,670 women from the Women's Health Initiative Memory Study who were cognitively unimpaired at enrollment. We used Cox proportional hazards models to assess associations between perceived social support with incident MCI, dementia, or either MCI/dementia during an average 10.7 (SD=6.1)-year follow-up. Modelling was repeated for emotional/information support, affection support, tangible support, and positive social interaction subscales of social support. Results: Among 6,670 women (average age=70 years [SD=3.8]; 97.0% non-Hispanic/Latina; 89.8% White), greater perceived social support was associated with lower risk of MCI/dementia after adjustment for age, ethnicity, race, hormone therapy, education, income, diabetes, hypertension, and body mass index (Tertile [T]3 versus T1: HR=0.85, 95% CI 0.74-0.99; ptrend=0.08). Associations were significant for emotional/information support (T3 versus T1: HR=0.84, 95% CI 0.72-0.97; ptrend=0.04) and positive social interaction (T3 versus T1: HR=0.85, 95% CI 0.73-0.99; ptrend=0.06) subscales. Associations were attenuated and not significant after adjustment for depressive symptom severity. Objective: Perceived social support, emotional/information support, and positive social interaction were associated with incident MCI/dementia among older women. Results were not significant after adjustment for depressive symptom severity. Improving social support may reduce risk of MCI and dementia in older women.