STUDY OBJECTIVE
To examine the association between light at night (LAN) and multiple sleep health dimensions.
METHODS
Among 47,765 Sister Study participants, indoor LAN (TV on in the room, light(s) on in room, light from outside the room, nightlight, no light) and sleep dimensions were self-reported at baseline (2003-2009). We used Poisson regression with robust variance to estimate adjusted prevalence ratios (PR) and 95% confidence intervals (CI) for the cross-sectional associations between LAN and short sleep duration (<7 hours/night), insomnia symptoms (difficulty falling or staying asleep), frequent napping (≥3 naps/week), inconsistent sleep/wake time (differed day-to-day and week-to-week), sleep debt (≥2 hours between longest and shortest duration), recent sleep medication use, and a cumulative poor sleep score (≥3 poor sleep dimensions). Population attributable risks (PARs) were determined for any light exposure vs. none by race/ethnicity.
RESULTS
Compared to sleeping with no light in the bedroom, sleeping with a TV on was associated with a higher prevalence of most dimensions of poor sleep (e.g., short sleep duration: PR=1.38, 95% CI: 1.32-1.45; inconsistent sleep/wake time: PR=1.55, 95% CI: 1.44-1.66; sleep debt: PR=1.36, 95% CI: 1.29-1.44; poor sleep score: PR=1.58, 95% CI: 1.48-1.68). PARs tended to be higher for non-Hispanic Black women compared to non-Hispanic white women.
CONCLUSIONS
Sleeping with a TV on was associated with poor sleep health among U.S. women, and non-Hispanic Black women may be disproportionately burdened.