title: Photoperiod at birth does not modulate the diurnal preference in asian population.
abstract: Two research groups reported that diurnal preference in Canadian and South European populations was modulated by the season of birth. The aim of the present study was to examine this association in the Japanese population. In this study, 1156 college students were administered the Morningness-Eveningness Questionnaire and asked the date and place of birth. Our results demonstrated that neither photoperiod nor season of birth modulated diurnal preference in the Japanese population. Two biological differences are reported to exist between Caucasians and Asians: polymorphisms of circadian clock genes and difference in ocular photosensitivity. These ethnic differences might characterize the circadian photosensitivity in infancy.
authors.affiliation: Department of Human and Information Science, Tokai University, Kanagawa, Japan. takao@keyaki.cc.u-tokai.ac.jp
authors.forename: Motoharu
authors.initials: M
authors.lastname: Takao
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Kurachi
authors.forename: Hikaru
authors.initials: H
authors.lastname: Kato
mesh_terms: D000293:Adolescent; D000328:Adult; D044466:Asian People; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D036801:Parturition / Q000502:physiology*; D017440:Photoperiod; D012621:Seasons; D011795:Surveys and Questionnaires; D014041:Tokyo; D055815:Young Adult