The SmartSleep Study is a comprehensive research initiative that was designed to evaluate the effects of night-time smartphone use on sleep patterns and overall health. Utilising an innovative approach, the study combines large-scale repeated surveys, high-resolution smartphone sensor data, in-depth clinical examinations, and linkage to nationwide health registries. This methodology enables detailed investigations into the physiological disruptions and long-term health consequences associated with disrupted sleep due to smartphone use. The study involves 30,673 participants, including subsets with high-resolution tracking data (n=5,927) collected via a custom app and deep clinical phenotypic data (n=245). In addition, 7,208 participants are followed through national registries for comprehensive data coverage and extended follow-up. This robust design provides a unique opportunity to explore the interplay between night-time smartphone behaviors, sleep disturbances, and associated health outcomes.

 

Principal investigator: Professor Naja Hulvej Rod

 

Cohort profile:

 

• Rod NH, Andersen TO, Severinsen ER, Sejling C, Dissing A, Pham VT, Nygaard M, Schmidt LKH, Drews HJ, Varga T, Freiesleben NC, Nielsen HS, Jensen AK (2023). "Cohort profile: The SmartSleep Study, Denmark, combining evidence from survey, clinical and tracking data". BMJ Open 13(10): e063588. Link

 

Key publications:

 

• Drews HJ, Sejling C, Andersen TO, Varga TV, Jensen AK, Rod NH (2024). "Tracked and self-reported nighttime smartphone use, general health, and healthcare utilization: results from the SmartSleep Study". Sleep 47(6): zsae024. Link

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• Andersen TO, Sejling C, Jensen AK, Dissing AS, Severinsen ER, Drews HJ, Sørensen TIA, Varga TV, Rod NH (2024). "Self-reported and tracked nighttime smartphone use and their association with overweight and cardiometabolic risk markers". Scientific Reports 14(1): 4861. Link
   

• Andersen TO, Sejling C, Jensen AK, Drews HJ, Ritz B, Varga TV, Rod NH (2023). "Nighttime smartphone use, sleep quality, and mental health: investigating a complex relationship". Sleep 46(12): zsad256. Link

 

• Severinsen ER, Andersen TO, Dissing AS, Jensen AK, Sejling C, Freiesleben NC, Nielsen HS, Rod NH (2023). "Night-time smartphone use, sleep duration, sleep quality, and menstrual disturbances in young adult women: A population-based study with high-resolution tracking data". Sleep Advances 4(1): zpad013. Link

 

• Otte Andersen T, Skovlund Dissing A, Rosenbek Severinsen E, Kryger Jensen A, Thanh Pham V, Varga TV, Hulvej Rod N (2022). "Predicting stress and depressive symptoms using high-resolution smartphone data and sleep behavior in Danish adults". Sleep 45(6): zsac067. Link

 

• Andersen TO, Dissing AS, Varga TV, Rod NH (2021). "The SmartSleep Experiment: Evaluation of changes in night-time smartphone behavior following a mass media citizen science campaign". PLoS One 16(7): e0253783. Link

 

• Dissing AS, Andersen TO, Nørup LN, Clark A, Nejsum M, Rod NH (2021). "Daytime and nighttime smartphone use: A study of associations between multidimensional smartphone behaviours and sleep among 24,856 Danish adults". Journal of Sleep Research 30(6): e13356. Link