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Circadian Rhythm of Cortisol and Estradiol in Healthy Women Karyn G

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Circadian Rhythm of Cortisol and Estradiol in Healthy Women Karyn G Wayne State University Wayne State University Dissertations 1-1-2011 Circadian rhythm of cortisol and estradiol in healthy women Karyn G. Butler Wayne State University, Follow this and additional works at: http://digitalcommons.wayne.edu/oa_dissertations Part of the Nursing Commons Recommended Citation Butler, Karyn G., "Circadian rhythm of cortisol and estradiol in healthy women" (2011). Wayne State University Dissertations. Paper 304. This Open Access Dissertation is brought to you for free and open access by DigitalCommons@WayneState. It has been accepted for inclusion in Wayne State University Dissertations by an authorized administrator of DigitalCommons@WayneState. CIRCADIAN RHYTHM OF CORTISOL AND ESTRADIOL IN HEALTHY WOMEN by KARYN G. BUTLER DISSERTATION Submitted to the Graduate School of Wayne State University, Detroit, Michigan in partial fulfillment of the Requirements for the degree of DOCTOR OF PHILOSOPHY 2011 MAJOR: NURSING Approved by: ________________________________________ Advisor Date ________________________________________ ________________________________________ ________________________________________ COPYRIGHT BY KARYN G. BUTLER 2011 All Rights Reserved DEDICATION This dissertation is dedicated to all those who have provided me with love, guidance and hope throughout this experience, especially my daughters, Kiri and Eva. ii ACKNOWLEDGEMENTS This dissertation would not have been possible without the support of the following people. I wish to acknowledge the guidance of my advisor, Dr. Jean Davis and the members of my committee, Dr. Nancy George, Dr. Hossein Yarandi and Dr. Janet Hankin. I would like to express my appreciation to the staff and faculty who have been instrumental in my development as a scholar. I wish to extend a special thank you to Dr. Rosalind Peters for being a constant resource and challenge to my ideas and assumptions throughout my doctoral study. I wish to thank my family and colleagues for their support and encouragement. I am especially grateful to Joan Visger for the hours of discussion on the philosophy and practice of science and nursing, the endless proofreading, editing, formatting and critique. Finally, a heartfelt thank you to the women at WSU who so generously contributed their time and energy by participating in this study. iii TABLE OF CONTENTS Dedication…………………………………………………………………………………………ii Acknowledgements………………………………………………………………………………iii List of Tables……………………………………………………………………………………..ix List of Figures…………………………………………………………………..………………....x Chapter 1: Introduction…………………………………………………………………………....1 Circadian Regulation………………………………………...……………………………2 Rhythm Misalignment and Health……………………………..…………………………6 Theories of Circadian Rhythm and Health………………………………………………..7 Sickness Behaviors……………………………………………..…………………………8 Prevalence of Illnesses Exhibiting Chronic Sickness Behaviors………………………….9 Alterations in Affect, Sleep Quality and Energy Level in Women……………………..11 Cortisol…………………………………………………..……………………………….14 Estradiol……………………………………………………………………...…………..15 Chronotype……………………………………………………………………………….16 Study Problem……………………………………………………………………………17 Study Purpose……………………………………………………………………………19 Significance…………………………………………...………………………………….20 Summary………………………………………………………………...……………….24 Chapter 2: Theoretical Framework and Literature Review…………………..………………….26 Cortisol/Estradiol Misalignment Hypothesis………………………….…………………26 Study C-T-E Model………………………………………………..…………………….29 Circadian Rhythm in Humans……………………………………………………………34 iv Chronotype………………………………………………………….……………………35 Circadian Rhythm of Affect……………………………………………………………..36 Chronotype and Affect…………………………………………………………..………39 Circadian Rhythm of Sleep Quality Patterns………………………………...…………..48 Chronotype and Sleep……………………………………………………………………56 Circadian Rhythm of Energy …………………………...……………………………….61 Chronotype and Energy………………………………………….………………………66 Circadian Rhythm of Affect, Sleep Quality and Energy Summary………………..……69 Circadian Regulation of Cortisol………………………………………….…………….69. Studies examining multiple cortisol values across the 24-hour day in affect, sleep quality and energy……………………………………………….…………72 Studies examining the cortisol slope…………………………………………..…85 Studies examining the relationship between cortisol and other rhythms………..96 Circadian rhythm of cortisol summary…………………..……………………..100 Circadian Regulation of Estradiol………………………….…………………………..100 Pilot Study…………………………………………………………..………………….103 Sample……………………………………………………………….………….105 Procedure…………………………………………………………………….…105 Analysis…………………………………………………………………………105 Results……………………………………………..……………………………106 CHAPTER 3: Research Method……………………………………………..…………………110 Design…………………………………………………………………………………..110 Human Subject…………………………………………………………………………112 v Sample……….......………………………………………….………………………….113 Inclusion criteria………………………………………………………..………114 Exclusion criteria…………………...…………………………………………..115 Recruitment……………………………………….…………….………………116 Setting………………………………………………………….….……………116 Major Study Variables……………………………………………………………….…116 Salivary cortisol……………………………………………..………………….117 Salivary estradiol…………………………………….…………………………117 Affect………………………………………………………………….………..117 Sleep quality……………………………………………………………………119 Energy ……..………………………………………......................…………….120 Screening variables……………………………….…………………………….124 Demographic variables…………………………………………..……………..124 Extraneous study variables……………………………………………………..124 Data Collection Procedure……………………………………………………………...125 Data Preparation………………………………………………………….…….…….…127 Missing Data……………………………………………………………………………128 Salivary Cortisol and Estradiol……………………………………………………...….128 Data Analysis……………………………………...……………………………………129 CHAPTER 4: Results of Data Analysis………………………………….…..…………………134 Introduction……………………………………………………….…………………….134 Sample Demographics……………………………………...…………………………..134 Descriptive Statistics for Major Study Variables…………………..……………….…..139 vi Reliability of the Cortisol and Estradiol Measures……………………………………..145 Findings Related to Study Aims and Hypotheses………………….……………..…….145 Specific aim 1………………………………………………………….……….145 Specific aim 2…………………………………………..………………………154 Specific aim 3……………………………………………………………….….157 Affect……………………………………………………..……….……157 Sleep quality…………………………………………………………….161 Energy……………………………………………..……………………162 Time of Wakening and Cortisol and Estradiol Parameters……………….…….………180 CHAPTER 5: Discussion, Conclusions and Recommendations……………………………….185 Introduction……………………………………………………………….……………185 Discussion of Sample Characteristics………………………………….……………….185 Discussion of Study Measures………………………………………………………….187 Affect…………………………………………………………….……………..187 Sleep quality……………………………………………..……………….……..188 Energy……………………………………………………………….………….189 Salivary measures………………………………………………………………190 Discussion of the Findings Related to Study Aims….………………..…….………….191 Specific aim 1…………………………………………………………………..191 Specific aim 2………………………………………….……………………….195 Specific aim 3……………………………………..……………………………195 Conclusions……………………………………………………………………………..198 Findings Related to Theoretical Framework…………………..………………………..198 vii Strengths and Limitations………………………………………………..……………..199 Strengths………………………………………..………………………………199 Limitations…………………………………………………..………………….200 Study Implications……………………………………………………………..……….201 Nursing research………………………………………………………………..202 Nursing practice………………………………………………...………………203 Summary………………………………………………………………………..203 Appendix A: HIC Approval………………………………….…………………………………205 Appendix B: Informed Consent…………………………………………………………….…..206 Appendix C: Flyer…………………………………………………………………..……….….210 Appendix D: Instruments………………………………………………………………….……211 References………………………………………………………………………………………226 Abstract………………………………………………………………………………….……...275 Autobiographical Statement…………………………………………………………..…….…..277 viii LIST OF TABLES Table 2.1. Pilot Study: Peaked Cosine Function with One Additional Harmonic…………..….108 Table 2.2. Pilot Study Scores on Subjective Measures………………………………...……….109 Table 3.1. Cronbach’s Alpha for Instruments Used with Study Sample……………….………123 Table 4.1. Sample Characteristics………………………………………………………..……..137 Table 4.2. Means and Inclusive Ranges for Major Study Variables……………...……………141 Table 4.3. Means and Inclusive Ranges for Major Study Variables by Chronotype…….….….142 Table 4.4. T-test for Significance in Health Measures Between M-types and E-types…..…….144 Table 4.5. Goodness of Fit for Cortisol and Estradiol Curve…………………………….…….148 Table 4.6. Curve Fit for Cortisol and Estradiol………………………………….……………..151 Table 4.7. Cortisol and Estradiol Curve Parameters Correlations in Full Sample and by Chronotype…………………………………………………………….………….....153 Table 4.8. Significance Test for Cortisol and Estradiol Curve Parameters Between M-types and E-types…………………………………………………………………………..156 Table 4.9. Goodness of Fit for Cortisol-Estradiol PAD and Health Indicator Measures for Full Sample………………………………………………………….........…………159 Table 4.10. Goodness of Fit for Cortisol-Estradiol PAD and Health Indicator Measures for M-types….........……………………...…………………………………...………..164 Table 4.11. Goodness of Fit for Cortisol-Estradiol PAD and Health Indicator Measures for E- types…………………………….........…………………………….………………166 Table 4.12. Optimal Cortisol-Estradiol PAD Based on Curve Fit……………..…….…………168 Table 4.13. Comparison of Energy and Fatigue VAS………………………………………….169 Table 4.14. Comparison of Circadian-dominant and Ultradian-dominant Curves on Demographic Variables and Rhythm Parameters……………...…..................……177 Table 4.15. Comparison of Circadian-dominant and Ultradian-dominant
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