THE ROLE OF SLEEP TIMING ON DIET QUALITY AND PHYSICAL ACTIVITY AMONG COLLEGE-AGED WOMEN PARTICIPATING IN THE UNIVERSITY OF MASSACHUSETTS VITAMIN D STATUS STUDY

ABSTRACT

Overweight and obesity are risk factors for chronic diseases such as cardiovascular disease and type-2 diabetes. Sleep has been associated with overweight and obesity. One potential mechanism by which sleep may lead to overweight and obesity is through positive energy balance, in which energy intake exceeds expenditure. There are few studies examining the impact of sleep timing (onset and wake time) on diet and exercise. In a cross sectional study, we examined associations between sleep timing (onset and wake time) and diet quality, as measured by the 2010 Dietary Guidelines for Americans Adherence Index (DGAI-2010), and in separate models, between sleep timing and meeting the 2008 Physical Activity Guidelines for Americans among the participants of the UMass Vitamin D Status Study. A total of 140 young women (aged 18 to 30 years) were grouped into four sleep timing categories based on the median of participants’ sleep onset and wake time (Early sleep-Early wake, Early sleep-Late wake, Late sleep-Early wake, Late sleep-Late wake). Multivariable linear regression was used to model the associations between the four sleep timing categories and diet quality adjusting for BMI, sleep duration, current smoking status, total energy intake, alcohol intake, and sedentary behavior. Multivariable logistic regression was used to model the association between sleep timing and meeting the National Physical Activity Guidelines, adjusting for BMI, sleep duration, current smoking status, and being a member of a sports team. Participants in the Early sleep-Early wake (EE) group, had the highest diet quality scores and were more likely to meet the National Physical Activity Guidelines compared to the other sleep timing categories. The Early sleep-Late wake (EL) group had significantly lower diet quality scores and were less likely to meet the National Physical Activity Guidelines. To our knowledge, this was the first study in the U.S. examining sleep timing and diet quality and physical activity among young women. In conclusion, the old adage early to bed, early to rise appears to be related to higher diet quality and meeting physical activity guidelines.