Neighborhood Walking Environment and Activity Level Are Associated with Obstructive Sleep Apnea: The Multi-Ethnic Study of Atherosclerosis.

BACKGROUND
There has been growing interest in understanding how neighborhoods may relate to cardiovascular risk. Neighborhood effects on sleep apnea may be one contributing mechanism. We investigated whether neighborhood walking environment and personal activity levels are related to obstructive sleep apnea.

METHODS
We analyzed data from a subpopulation of the Multi-Ethnic Study of Atherosclerosis (MESA), including subjects who participated in both MESA Sleep and Neighborhood studies (n=1,896). Perceived neighborhood walking environment and subjects' objective activity were evaluated in multivariate, multi-level models for an association with sleep apnea severity as defined by the apnea hypopnea index. Sex, race/ethnicity and obesity were examined as moderators.

RESULTS
Residing in the lowest quartile walking environment neighborhoods (score <3.75) was associated with more severe sleep apnea [mean 2.7 events/hr greater AHI, 95% CI (0.7, 4.6)], after adjusting for demographics, body mass index, co-morbidities, health behaviors, neighborhood socio-economic status and site. Associations were stronger among obese and male individuals. Approximately one standard deviation greater objective activity in men, was associated with a lower AHI [mean -2.4 95% CI (-3.5, -1.3) events/hr]. This association was partially mediated by body mass index (P<0.001).

CONCLUSIONS
Living in neighborhoods with a low walking environment score is associated with greater sleep apnea severity, especially in male and obese individuals. In men, greater activity level is associated with less severe sleep apnea, independent of body mass index, co-morbidities and socio-economics. Neighborhood-level interventions that increase walkability and enable increased physical activity may potentially reduce sleep apnea severity.