Xiao, Q., Gee, G., Jones, R. R., Jia, P., James, P., & Hale, L. (2019). Cross-sectional association between outdoor artificial light at night and sleep duration in middle-to-older aged adults: The NIH-AARP Diet and Health Study. Environ Res, 180, 108823.
Abstract: INTRODUCTION: Artificial light at night (ALAN) can disrupt circadian rhythms and cause sleep disturbances. Several previous epidemiological studies have reported an association between higher levels of outdoor ALAN and shorter sleep duration. However, it remains unclear how this association may differ by individual- and neighborhood-level socioeconomic status, and whether ALAN may also be associated with longer sleep duration. METHODS: We assessed the cross-sectional relationship between outdoor ALAN and self-reported sleep duration in 333,365 middle- to older-aged men and women in the NIH-AARP Diet and Health Study. Study participants reported baseline addresses, which were geocoded and linked with outdoor ALAN exposure measured by satellite imagery data obtained from the U.S. Defense Meteorological Satellite Program's Operational Linescan System. We used multinomial logistic regression to estimate the multinomial odds ratio (MOR) and 95% confidence intervals (CI) for the likelihood of reporting very short (<5h), short (<7h) and long (>/=9h) sleep relative to reporting 7-8h of sleep across quintiles of LAN. We also conducted subgroup analyses by individual-level education and census tract-level poverty levels. RESULTS: We found that higher levels of ALAN were associated with both very short and short sleep. When compared to the lowest quintile, the highest quintile of ALAN was associated with 16% and 25% increases in the likelihood of reporting short sleep in women (MORQ1 vs Q5, (95% CI), 1.16 (1.10, 1.22)) and men (1.25 (1.19, 1.31)), respectively. Moreover, we found that higher ALAN was associated with a decrease in the likelihood of reporting long sleep in men (0.79 (0.71, 0.89)). We also found that the associations between ALAN and short sleep were larger in neighborhoods with higher levels of poverty. CONCLUSIONS: The burden of short sleep may be higher among residents in areas with higher levels of outdoor LAN, and this association is likely stronger in poorer neighborhoods. Future studies should investigate the potential benefits of reducing light intensity in high ALAN areas in improve sleep health.
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Zabiliute, A., Vaicekauskas, R., Vitta, P., & Zukauskas, A. (2014). Phosphor-converted LEDs with low circadian action for outdoor lighting. Opt Lett, 39(3), 563–566.
Abstract: Dichromatic phosphor-converted (pc) light-emitting diodes (LEDs) with low circadian action are proposed for low-luminance photobiologically safe outdoor illumination. The LEDs feature the partial conversion of blue radiation in an orange phosphor with the resulting correlated color temperature in the “firelight” range of 1700-2500 K. The circadian action factor, which is the ratio of the biological efficacy of radiation due to the excitation of intrinsically photosensitive retinal ganglion cells to the mesopic luminous efficacy of radiation, is considerably lower than that of commercial white pc LEDs. The equivalent general color-rendering index estimated with regard to the reduced color-discrimination ability of human vision at low luminances has appropriate values in between those of common white pc LEDs and high-pressure sodium lamp.
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