Examining the associations of endogenous hormones and phthalate exposure with sleep in midlife women

Poor sleep is among the adverse symptoms that women develop as they age. Midlife women who report poor sleep are at an increased risk of developing depressive symptoms, reporting a poor quality of life, and experiencing overall impaired health quality. Therefore, understanding what risk factors influence sleep in midlife women is critical in order to identify potential areas for intervention. Endogenous hormones, including follicle stimulating hormone (FSH), estradiol, and progesterone, undergo significant changes during midlife. These changes are potential risk factors for menopausal symptoms, including sleep disruptions, hot flashes, and depression. Furthermore, exposure to environmental chemicals, including phthalates, further disrupt these hormones. Therefore, it is likely that exposure to phthalates contribute to the development of adverse symptoms during midlife. Phthalates are a class of industrial plasticizers and stabilizers used in a wide variety of consumer products, including medical plastics, food packaging, cosmetics, personal care products, and fragrances. Exposure to phthalates has been associated with sleep problems in adult men and women. However, no studies have examined the association between phthalates and sleep in women of advanced reproductive age. In my dissertation, I examined how endogenous hormones and exposure to phthalates are associated with sleep in two populations of midlife women. To accomplish this, I conducted studies with two separate populations of midlife women. First, I completed my first two studies (Chapters 3 and 4) with the Midlife Women’s Health Study (MWHS). The MWHS is a longitudinal cohort study with the primary goal of identifying risk factors for hot flashes in perimenopausal women. In my first study, I determined what hormones and phthalate measures were associated with frequency of self-reported sleep disruptions in participants of the MWHS using data from year 1 of this study (CHAPTER 3). Further, I identified if hormones mediated the association between phthalates and sleep disruptions in this population. In my second study, I examined the association between changes in symptoms (i.e. depression and sleep disruptions) across multiple years of the MWHS (CHAPTER 4). I further explored how changes in these symptoms were associated with changes in hormones. Additionally, using a Bayesian network approach, I determined the associations between multiple factors related to sleep disruptions, including race, hormones, menopause status, hot flashes, depression, and quality of life. The second population of women I worked with was the Carle Midlife Women’s Sleep Study (CMWSS). This study was designed to identify the associations of hormones and phthalate exposure with both objective and subjective measures of sleep. Therefore, in my third study, I evaluated the associations of hormones and phthalate exposure with both objective and subjective measures of sleep, as well as depression, in participants of the CMWSS (CHAPTER 5). My studies have assessed additional risk factors for sleep and depression in midlife women. Specifically, I found that hormones beyond FSH and estradiol are associated with measures of sleep. Additionally, I am among the first to detect associations between phthalate exposure and menopausal symptoms. Furthermore, using either mediation analysis or Bayesian network analysis, I established how multiple variables may work together to influence sleep in menopausal women. Finally, I identified that measures of hormones and phthalates may be differentially associated with sleep measured objectively versus subjectively. Collectively, my data contribute to the growing body of literature identifying potential targets for intervention to improve overall quality of life and health in aging women.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Neuroscience

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Hatcher, Katherine M.

Contributors dc:contributor

• Mahoney, Megan M
• Flaws, Jodi A
• Raetzman, Lori T
• Smith, Rebecca L
• Davies, Charles R

• Menopause
• sleep
• phthalates
• depression
• women
• hormones

Statement dc:rights

• Copyright 2020 KATHERINE M. HATCHER

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/108571

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/108571