MedicalResearch.com Interview with:
Dr. Kathryn Orzech PhD
Postdoctoral fellow,Charting the Digital Lifespan
University of Dundee, Scotland, UK
MedicalResesarch.com: What are the main findings of the study?
Dr. Orzech: We found that acute illnesses, such as colds, flu, and gastroenteritis were more common among healthy adolescents with shorter sleep. Specifically, our main analysis found that reported bouts of illness (analyzed on a bouts-of-illness-per-interview basis) declined with longer sleep for both male and female high school students. Longer sleep was also generally protective against school absences that students attributed to illness. There were sex differences, with males reporting fewer illness bouts than females, even with similar sleep durations. This is consistent with another recent study that showed a lower impact of shorter sleep on male adolescents (in that case the outcome was male adiposity), but more research is needed.
We also conducted a secondary analysis to examine total sleep time in matched 6-day windows before illness and before wellness in the same adolescents. Although the number of participants who met our strict criteria for a healthy 6-day window before illness or wellness was only 18 (I was amazed at how difficult it was to find adolescents who reported being completely well for 6 consecutive days), we were able to see a trend in the data toward shorter sleep before illness vs. wellness. Because of the difficulty in comparing sleep before illness vs. wellness, we conducted a qualitative analysis as well, choosing two 17 year old males who were both shorter sleepers, but who reported very different illness profiles - 0 days of illness vs. 35 days of illness across the school term. An in-depth look at notes made by interviewers allowed us to create brief case studies to illustrate that not all shorter sleepers are alike. More irregular sleep timing across weeknights and weekends (much shorter sleep during the week and longer sleep times on the weekend), and a preference for scheduling work and social time later in the evening hours may both contribute to differences in illness outcomes.
(more…)