Neurology
Sleep disturbance and neighborhood disadvantage interact to affect cognitive health in older Mexican Americans Yu Yu* Yu Yu Shiwen Li Kimberly Paul Beate Ritz
Background: Both sleep disturbance and neighborhood disadvantage have been separately linked to cognitive impairment. Here, we aim to examine how sleep disturbance and neighborhood disadvantage interact to influence the development of incident dementia or cognitive impairment without dementia (CIND) among older Mexican Americans followed over almost a decade for cognitive decline.
Methods: We used 1,582 Mexican American participants from the Sacramento Area Latino Study on Aging conducted from 1998 to 2007. Sleep disturbance was defined according to five questions such as waking up to urinate during night and having trouble falling asleep at baseline and was converted into a standardized score (z-score). A neighborhood disadvantage index was created via principal component analysis based on percent of population with education below high school, linguistically isolated households, population with income below federal poverty line, population that were unemployed from 2010 American Community Survey. Using Cox proportional hazard models, we estimated the hazard of incident dementia or CIND according to the sleep disturbance score and further investigated whether neighborhood disadvantage modified the association between sleep disturbances and dementia or CIND.
Results: In total, 96 incident dementia and 150 incident dementia/CIND cases were identified during 10-years of follow-up. For each 1 standard error increase in the sleep disturbance score, the hazard of incident dementia increased 24% (HR= 1.24, 95%CI: 1.00, 1.55). The hazard ratio for sleep disturbance related dementia was stronger (HR=1.41, 95% CI: 1.04, 1.91) among those living in the disadvantaged neighborhood areas compared to those living in the advantaged areas.
Conclusion: Our study indicates that sleep disturbances adversely affect cognition in older Mexican Americans and that this effect may be modified by neighborhood disadvantages such that cognitive function in vulnerable populations is most affected.