Figure 6. Similarity between Parkinson's disease prevalence and sky light pollution in U.S.A.

The prevalence of Parkinson's disease in U.S.A. (a) was reproduced from Willis et al.¹⁴ (with permission from S. Karger AG, Medical and Scientific Publishers, Allschwilerstrasse 10, 4009 Basel, Switzerland).The sky light pollution map of the U.S.A. (b) was obtained with permission from the Earth Observation Group (National Oceanic and Atmospheric Administration (NOAA) and the Department of Commerce, web site: http://www.ngdc.noaa.gov/dmsp/dmsp.html).