Abbreviations: AD, Alzheimer’s dementia; APOE4, apolipoprotein E ε4 genotype; COPD, chronic obstructive pulmonary disease; IQR: interquartile range; LAN: light at night; MCI: mild cognitive impairment, VIIRS: Visible Infrared Imaging Radiometer Suite. The gene discussed is APOE; the disease is Alzheimer disease.