Quantitative analysis of human chronotypes [Elektronische Ressource] / vorgelegt von Tim Kühnle

Tim Kühnle

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• Gesundheit

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• Publié par: ludwig-maximilians-universitat_munchen
• Publié le: 01 janvier 2006
• Nombre de lectures: 33
• Langue: English
• Poids de l'ouvrage: 7 Mo

Extrait

Quantitative Analysis of Human Chronotypes
Dissertation
der Fakult?t f?r Biologie
der Ludwig-Maximilians-Universit?t M?nchen
zur Erlangung des
naturwissenschaftlichen Doktorgrades
Angefertigt am
Zentrum f?r Chronobiologie
Institut f?r Medizinische Psychologie
Ludwig-Maximilians-Universit?t M?nchen
vorgelegt 2006
von Tim K?hnle
geboren in Schw?bisch HallArbeit eingereicht am: 31. Januar 2006
1. Gutachter / Pr?fer: Prof. Gisela Grupe
2. / Pr?fer: Prof. Susanne Foitzik
3. Pr?fer: Prof. Thomas Cremer
4. Pr?fer: Prof. Gerhard Haszprunar
Sondergutachter: Prof. Till Roenneberg
Tage der m?ndlichen Pr?fung: 13. April 2006In Memoriam
Dr. Klaus Pasold
(1947-2004)Contents
1. Introduction
1.1. Rhythmicity, a general quality of life 1
1.2. The four circa rhythms 2
1.2.1. Circannual rhythms 2
1.2.2. Circatidal and circalunar rhythms 3
1.2.3. Circadian rhythms 4
1.3. Biological oscillators 4
1.3.1. Clocks and zeitgeber 4
1.3.2. Entrainment 5
1.3.2.1. The two models of entrainment 5
1.3.2.2. Phase response curve (PRC) 6
1.3.2.3. Different clocks are entrained differently 9
1.4. The mammalian circadian clock(s) 10
1.4.1 Localizing the central mammalian clock 10
1.4.2 Circadian photoreception 11
1.4.3 The suprachiasmatic nucleus (SCN) 11
1.4.3.1. Determination of the SCN as the central circadian pacemaker 11
1.4.3.2. Synchronization within the SCN 12
1.4.3.3. Input signals of the SCN 12
1.4.3.4. Output signals of the SCN 13
1.4.4. Peripheral oscillators 13
1.4.5. Clock genes 14
1.4.5.1. Clock genes from unicells to mammals 14
1.4.5.2. The mammalian molecular circadian clock 14
1.4.6. A net of oscillators 17
1.4.6.1. Different levels of oscillations 17
1.4.6.2. Morning-Evening (M-E) oscillator 18
1.5. Human chronobiology 18
1.5.1. Pros and Cons of human circadian research 18
1.5.2. Endogenous human circadian rhythms 18
1.5.3. Entrainment of human rhythms 20
IContents
1.5.4. Investigating human endogenous rhythms 21
1.5.5. Sleep and (circadian) sleep disorders 21
1.5.5.1. Sleep basics 21
1.5.5.2. The two-oscillator model of sleep and wakefulness 22
1.5.5.3. Circadian rhythm sleep disorders (CRSD) 23
1.5.6. Human clock genes 24
1.5.7. Chronobiology and health 25
1.5.7.1. The circadian clock in modern times 25
1.5.7.2. The clock and pathology 26
a) Circadian rhythm of diseases 26
b) From the circadian clock to diseases 26
c) Shift work and sleep dept 27
1.6. Morningness-Eveningness vs Chronotype 28
1.6.1. The Horne-?stberg Morningness-Eveningness questionnaire (MEQ) 28
1.6.2. Disadvantages of the MEQ 29
1.6.3. Questionnaires in the context of quantitative genetic analysis 30
1.6.3.1. Qualitative vs quantitative scale 30
1.6.3.2. Human chronotype is heavily masked by environmental influences 30
1.7. Aims of this work 31
2. Material & Methods 32
2.1. Munich ChronoType Questionnaire (MCT-Q) 32
2.1.1. Properties of the Munich ChronoType Questionnaire 32
2.1.2. Versions of the MCTQ 32
2.1.3 Available languages 35
2.2. Munich ChronoType Sleep Log (MCT-SL) 36
2.2.1. Properties of the Munich ChronoType Sleep Log 36
2.2.2. Evaluation of sleep log data 36
2.3. Distribution of MCTQ & Sleep log 38
2.3.1. MCTQ 38
IIContents
2.3.2. Sleep log 38
2.4. Definition of the phase marker for chronotype and 39
classification of extreme chronotypes
2.4.1. List of abbreviations 39
2.4.2. Mid-sleep on free days and its correction 40
2.4.3. Use of MS and MS and classification of extreme chronotypes 42F FSc
2.5. Statistical methods and models 43
2.6. Software 44
3. Results 46
3.1. Data collection 46
3.1.1 MCTQ 46
3.1.2. Sleep log (MCT-SL) 47
3.2. Validation of the Munich Chronotype Questionnaire 48
3.2.1. Test – Retest – Reliability 48
3.2.2. Validity of the MCTQ and MS as phase marker for chronotype 53FSc
3.2.3. Factors influencing precision of chronotype assessment 58
3.2.3.1. Variation in actual sleep times on free days 58
3.2.3.2. Differences between MS and MS 60W F
3.3. Classification of chronotypes 62
3.3.1. Correlations of MCTQ variables 62
3.3.2 Normalization for MS 63FSc
3.3.3. Can one determine sub-groups within the sample population of
chronotypes? 65
3.3.4 Confirmatory Factor Analysis 67
3.3.4.1. Conditions of confirmatory Factor Analysis
(Principle Component Analysis) 67
3.3.4.2. Testing assumptions of sampling adequacy 68
a) Multicollinearity 68
IIIContents
b) Anti-Image-Matrix 68
c) Bartlett's test of spericity 69
3.3.4.3. Results of confirmatory Factor Analysis 69
a) Factor extraction 69
b) Communalities 70
c) Factor loadings 70
d) Interpretation of factors (F1, F2, F4) 72
e) of factors (F3) 73
f) Differences between Gender and Age groups 74
3.3.5.4. Conclusions 75
3.4. Biological and social factors associated with chronotype 76
3.4.1. Defining biological and social factors 76
3.4.2. Association of chronotype with biological and social factors 77
3.4.2.1. Multiple regression model 77
3.4.2.2. Testing accuracy of regression model 78
a) General assumptions 78
b) Deviation from normal distribution 79
c) Age dependency of MS and SLD 80FSc ?
3.4.2.3. General regression model 81
a) MS 81FSc
b) SLD 82?
3.4.2.4. Regression models for Work days and for Free days 84
a) MS and MS 84W F
b) SLD and SLD 86W F
c) Summary for differences between Work days and Free days 86
3.4.2.5. Regression models for Age groups and Gender 88
a) MS 88FSc
b) SLD 90?
c) Summary and conclusion for Age and Gender differences 90
3.4.2.6. Conclusions 91
3.4.3 Interaction of factors 92
3.4.3.1. Objectives 92
3.4.3.2. Sub-grouping the sample population 92
3.4.3.3. (In) Accuracy of model 93
3.4.3.4. Effects and interactions between independent variables 93
3.4.3.5. Conclusions 96
IVContents
4. Discussion 97
4.1. Validation of the MCTQ 97
4.1.1. MCTQ vs MCTQ (Test-Retest-Reliability) 97
4.1.2. MCTQ vs Sleep log 98
4.2. Complexity of the MCTQ 99
4.3. Factors associated with chronotype 101
4.3.1. Statistical models 101
4.3.2. AGE 102
4.3.3. GENDER 103
4.3.4. Average daily outside light exposure (? DOLE),
Photoperiod (PHOTO), and Latitude (LAT) 103
4.3.5. Place of residence (POR) 105
4.3.6. Body mass index (BMI) 106
4.3.7. Interactions 106
4.4. Conclusions & recommendations 107
4.4.1. Improvement of the MCTQ 107
4.4.2. Properties of chronotype 108
4.4.3. Factors associated with chronotype 109
5. Summary / Zusammenfassung 110
5.1. Summary 110
5.2. Zusammenfassung 112
6. References 114
7. Erkl?rung 132
8. Curriculum vitae 133
9. Acknowledgements 134
VContents
Appendix 1: Figures 135
Appendix 2: Munich ChronoType Questionnaire (MCTQ) 136
Appendix 3: MCTQ – Improved version 139
Appendix 4: Sleep log 140
Appendix 5: All sleep logs from Germany 141
Appendix 6: Cities >100 000 residents 142
Appendix 7: SPSS Syntax 143
VIIntroduction
1. Introduction
1.1. Rhythmicity, a general quality of life
The central issue of evolution is the selection of randomly occuring genetic modifications
(mutations) beneficial for the adaptation to environmental conditions that define ecological
niches (Darwin 1859). While spatial niches (biotopes) consist of different geological and bio-
logical structures (e.g. rain forest, desert, mountains, deep temporal niches
(chronotopes) comprise time structures like day and night, seasons, and moon phases. (Ro-
enneberg 1992). Adaptation to spatial niches is reflected by an organisms morphology (e.g.
lungs vs. gills) that does not change in general throughout life because spatial niches are
usually not left. Temporal niches in contrast undergo various repeating changes caused by i)
earths rotation around the sun, ii) earths rotation around its own axis, and iii) the moons rota-
tion around earth. Thus, as soon life became dependent on conditions affected by one or
more of these astronomical phenomenons (light, temperature, humidity,?) it had to cope
with rhythmic changes in order to use opportune ranges of these conditions as well as to
avoid the unfavourable ones.
Rhythmically changing environmental conditions are challenges for every organism. There-
fore, it is important to be prepaired for either advantageous or disadvantageous
rather than just reacting to them. For any organism that is prey of another it is vitally impor-
tant to know at which time of the day predators are most likely around. The same reasons
apply for animals inhabiting the beach in order to know when the tide is low or high. Fured
animals need their winter fur before temperature starts to decrease drastically in autumn and
the photosynthetic machinery of plants must be fully working by the first rays of sunlight. Bio-
logical clocks - reflecting rhythms caused by the interplay of sun, moon, and earth - make it
possible to anticipate forthcoming changes in the environment.
Rhythmicity can be found in all organisms, ranging from production/degradation of mole-
cules to fluctuations within and between whole populations. Different classes of rhythms
have been defined: rhythms with periods shorter than one day are called ultradian (for re-