Cohort profile: The SmartSleep Study, Denmark, combining evidence from survey, clinical and tracking data.

PURPOSE: The SmartSleep Study is established to comprehensively assess the impact of night-time smartphone use on sleep patterns and health. An innovative combination of large-scale repeated survey information, high-resolution sensor-driven smartphone data, in-depth clinical examination and registry linkage allows for detailed investigations into multisystem physiological dysregulation and long-term health consequences associated with night-time smartphone use and sleep impairment. PARTICIPANTS: The SmartSleep Study consists of three interconnected data samples, which combined include 30 673 individuals with information on smartphone use, sleep and health. Subsamples of the study population also include high-resolution tracking data (n=5927) collected via a customised app and deep clinical phenotypical data (n=245). A total of 7208 participants are followed in nationwide health registries with full data coverage and long-term follow-up. FINDINGS TO DATE: We highlight previous findings on the relation between smartphone use and sleep in the SmartSleep Study, and we evaluate the interventional potential of the citizen science approach used in one of the data samples. We also present new results from an analysis in which we use 803 000 data points from the high-resolution tracking data to identify clusters of temporal trajectories of night-time smartphone use that characterise distinct use patterns. Based on these objective tracking data, we characterise four clusters of night-time smartphone use. FUTURE PLANS: The unprecedented size and coverage of the SmartSleep Study allow for a comprehensive documentation of smartphone activity during the entire sleep span. The study has been expanded by linkage to nationwide registers, which allow for further investigations into the long-term health and social consequences of night-time smartphone use. We also plan new rounds of data collection in the coming years.

Agreement between the Danish Cancer Registry and the Danish Lung Cancer Registry.

INTRODUCTION: The Danish Cancer Registry (DCR) and the Danish Lung Cancer Registry (DLCR) are nation-wide registries recording Danish patients with lung cancer (LC). The aim of this study was to assess data agreement and possible consequences hereof on estimation of survival between patients in the two registries. METHODS: Descriptive statistics were used for comparison of registered patients in 2013-2014 in the DCR and the DLCR. Furthermore, the one-year relative survival (1y-RS) and Cox proportional mortality hazard rates (MRR) were calculated. RESULTS: In 2013-2014, a total of 9,111 Danish residents were identified with LC in the DCR and 9,316 were found in the DLCR. Merging the two registries showed an agreement of 87%, whereas 6% were included only in the DCR and 8% only in the DLCR. Including patients only registered in one registry, but who seemed to meet the inclusion criteria of both registries, would increase the agreement to 95%. No differences were seen for 1y-RS. However, MRR for patients in the DLCR was significantly lower than for patients in the DCR: 0.94 (95% confidence interval: 0.91-0.98). CONCLUSIONS: Surprisingly, the DCR registered fewer patients in 2013-2014 than the DLCR, even though they employ the same primary data source. The agreement between the DCR and the DLCR was 87%; this may be increased to 95% if patients who seemed to meet the inclusion criteria of the other register were also included. The discrepancies found were mainly due to different definitions of dates of diagnosis, registrations probably missed by the algorithms and possible registration errors. Discrepancies resulted in a significant difference in MRR, but not in 1y-RS. FUNDING: none. TRIAL REGISTRATION: not relevant.