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CTS Summer Student Investigates Sleep and Cytokines

About the Author

My name is Sarah and I am a university student majoring in in biological sciences. I compete on the Women’s Volleyball team and I am a member of Student Leadership. I have always been curious about the world around me, so when I stepped into my first biology class I knew I had finally found a subject that was truly fun for me in school. However, I also have a passion for art and creativity. My goal is to become a dermatologist and open my own skincare line so that I can combine my passions.


This experience as a summer intern on the California Teachers Study has pushed me to open my mind more by forcing the quantitative and creative sides of my mind to come together to draw conclusions from data. I am looking forward to continuing to learn and create in whatever opportunities life hands me in the future.


Sarah, a CTS summer student, presents her poster on the association between sleep characteristics and cytokine levels

My Research Project

For my project, I worked with Dr. Sophia Wang to study which risk factors might be associated with elevated/abnormal cytokine levels among California Teachers Study participants. Cytokines are hormone-like proteins that are part of the immune system and trigger certain responses such as inflammation. Chronic inflammation and over-active immune responses have been linked to an increased risk of cancer and other diseases.

The goal of this project was to determine if a participants' quality of sleep was associated with having elevated cytokine levels. Poor sleep is linked to many diseases, such as inflammatory bowel disease, cancer, and cardiovascular disease. Inflammation plays a key role in each of these diseases, and previous students have reported significant associations between sleep activity and increased levels of a few inflammatory biomarkers.

This project broadly investigated the association between sleep characteristics and inflammation by measuring cytokine levels. We hypothesized that irregular and poor sleep characteristics would be associated with increased levels of inflammatory cytokines.

We used data from 822 women who answered Questionnaire 5—disseminated in 2012—and had donated a blood sample to the study. The 822 women selected were sampled based on their sleep characteristics and had to have both donated blood and completed questionnaire 5.

This project focused on analyzing the levels of 16 cytokines, and comparing those cytokine levels with participant responses about their personal sleep quality and chronotype, i.e. whether they were a morning vs. evening person.

Our preliminary results indicated that there may be an increased risk of certain elevated inflammatory cytokines associated with participants who reported having “very bad sleep”. These results are consistent with our hypothesis that poor sleep is associated with elevated levels of inflammatory markers. Our evaluation of chronotype, however, did not yield any consistent associations with cytokine levels.

In this project we only examined the associations between sleep and cytokines; however, there are many other variables that may have an influence, such as age, BMI, smoking, diet, etc. In the future we would like to construct a multivariate model that includes potential confounders. After looking at all the possible variables that may be associated to inflammation and elevated cytokines we can more confidently state possible risk factors.

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