Sleep Duration, Diet Quality and Type 2 Diabetes

Abstract

Type 2 diabetes has reached epidemic proportions globally, and accumulating evidence suggests extremes of sleep duration increase risk. Diet may be an important mechanism, yet few studies examine prospective relationships of sleep duration and diet quality or whether diet explains associations of sleep duration with childhood obesity or diabetes in adults. In Chapter One, we report a moderate correlation between self-reported sleep duration and actigraphy in Sueño, the sleep ancillary study to the Hispanic Community Health Study/Study of Latinos. Chapter Two identifies associations of chronic insufficient sleep duration since infancy with lower diet quality in mid-childhood in Project Viva: children with the least favorable diet and sleep have the highest body mass index z-scores in mid-childhood, but diet does not explain associations with adiposity. In Chapter Three, adherence to healthful dietary patterns reduces risk of diabetes in the Women’s Health Initiative; high quality diets are protective in all groups, but race/ethnicity modifies associations. In Chapter Four, we find that changes in sleep duration, increases in particular , are associated with diabetes and concomitant changes in diet quality, physical activity and weight in the Nurses’ Health Study. Each of these studies contributes new knowledge: Sueño represents the largest sleep validation to date, the only validation among Hispanic/Latinos and allows researchers to better understand the information contained in (and the limitations of) self-reported measures of sleep duration within subgroups. In the Women’s Health Initiative, we address limitations of the current literature on dietary patterns by calculating four dietary indices within the same cohort, standardizing the scores for comparison and examining associations across racial/ethnic groups. Project Viva is the first study to examine the influence of chronic insufficient sleep on diet quality in childhood when health behaviors and dietary preferences are being formed. Finally, examining changes in sleep duration and changes in diet quality, physical activity and weight in the Nurses’ Health Study represents a novel way to leverage repeated assessments. Results of this dissertation may help build the case for policy and intervention efforts to prevent and treat obesity and diabetes, particularly those that seek to improve both sleep and diet.