Examining the Relationship Between Sleep and Obesity Using Subjective and Objective Methods
The increasing prevalence of overweight and obese individuals in the United States makes it imperative to study the various causal factors of obesity. Overweight and obesity are typically thought to be caused by an energy imbalance and a majority of research efforts today focus on studying strategies using diet and physical activity to reduce obesity. Unfortunately, despite decades of effort the struggle with obesity continues for many. Other putative causes of obesity such as sleep quantity and quality need to be further explored. With the causes of obesity being multifaceted, it is important to look beyond energy imbalance and find new clues for solving the obesity puzzle.
In order to explore the relationship between obesity and sleep, we have designed two studies and will explore this relationship in both prospective and retrospective ways. In the first prospective study, we compare sleep, body weight, and physical activity in children and adults using both objective and subjective tools. There is extensive evidence showing familial relationships with obesity. Sleep patterns and habits may also have ties to the family. Our first objective of the study is to compare sleep amounts in children and adults using these methods. Our second objective is to explore the relationship between sleep amount and body adiposity in the families. We will compare two new objective measures of sleep with a subjective method (sleep log). We hypothesized that the sleep assessment tools will report similar sleep amounts in children and adults. In our second study, we retrospectively examined sleep across the life cycle in females including women who are pregnant. This was a cross-sectional study. We used an objective measure to compare bed times, wake times, and sleep amounts in pregnant compared to non-pregnant women. We hypothesize, that pregnant females will have shorter sleep duration, especially at the later measurement period of 35 weeks gestation, compared to non-pregnant females due the added physical discomfort of pregnancy.
This thesis will begin with a literature review focused on obesity, sleep, body composition assessment, physical activity assessment, and sleep assessment. The following sections include the family study manuscript and the female study manuscript each of which includes an abstract, introduction, methods, data analysis, results, and discussion for each manuscript. Following the manuscripts are the conclusions, appendices, references, and acknowledgements.