Sleep, Diurnal Preference, Health, and Psychological Well-being: A Prospective Single-Allelic-Variation Study

Abstract

Individual differences in sleep and diurnal preference associate with physical and mental health characteristics, but few genetic determinants of these differences have been identified. A variable number tandem repeat (VNTR) polymorphism in the PERIOD3 (PER3) gene (rs57875989) has been reported to associate with diurnal preference, i.e., preferred timing of waking and sleep. Here, the authors investigate in a prospective single-candidate genetic variant study whether allelic variation for this polymorphism associates also with reported actual sleep timing and sleep duration, as well as psychological and health measures. Six hundred and seventy-five subjects, aged 20 to 35 yrs, completed questionnaires to assess sleep and psychological and health characteristics and were genotyped for the PER3 VNTR. Homozygosity for the longer allele (PER3^5/5) of the VNTR was associated with increased morning preference, earlier wake time and bedtime, and reduced daytime sleepiness. Separate analyses of work and rest days demonstrated that the increase in time in bed during rest days was greatest in PER3^5/5 homozygotes. PER3 genotype modified the effects of sleep timing and duration on fluid intelligence and body mass index. Genotype was not associated with physical or psychological characteristics as assessed by the SF-36 Health Questionnaire, the General Health Questionnaire, the Big Five Inventory, the Behavioral Inhibition System–Behavioral Activation System scales, and the Positive and Negative Affect Scale, even though these measures varied significantly with diurnal preference as assessed by the Morningness-Eveningness Questionnaire. Whereas diurnal preference also predicts mental health and psychological characteristics, as well as sleep timing, the PER3 VNTR specifically affects measures of sleep timing and may also modify the effects of sleep on health outcome measures. (Author correspondence: [email protected])

Keywords:

• Body mass index
• Clock genes
• Diurnal preference
• Genetic polymorphism
• Intelligence
• Per3
• Sleepiness

ACKNOWLEDGMENTS

This work was supported by BBSRC (BB/F022883/1), AFOSR (FA-9550-08-1-0080), and Philips Lighting. Any opinions, findings, and conclusions or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of the Office of Naval Research/AFOSR or the other funding agencies. We thank Dr. Sigurd Johnsen and Mr. Patrick McGabe for statistical advice, and Dr. Sibah Hasan and the staff of the Surrey Clinical Research Centre for their help.

Declaration of Interest: The authors report no conflicts of interest related to the topic of this publication. The authors alone are responsible for the content and writing of the paper.