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Introduction: Research has provided novel insights into how light stimulates circadian rhythms through specialised retinal ganglion cells to the suprachiasmatic nucleus. In addition, there has been a revolution in light-emitting diode (LED) technology, leading to tunable LED light sources and lighting systems, enabling 24-hour dynamic light scenarios with bright blue-enriched short wavelength light during the day and dim evening light, stimulating the circadian system. These dynamic LED lighting systems are now being implemented at hospitals without adequate understanding of how it may affect the health and well-being of patients and staff., Methods and Analysis: An optimised dynamic LED lighting scenario is investigated at a newly built psychiatric hospital in Copenhagen. In the 12 months baseline period, a standard lighting scenario with dynamic colour temperature and fixed light intensity is investigated. In the following 12-month intervention period, a new DEL scenario is investigated, having dynamic colour temperature as well as dynamic light intensity with a higher daytime and lower evening-time melanopic daylight equivalent illuminance. This setting is furthermore adjusted for geographical orientation to compensate for differences in sunlight access in wintertime. The study uses a quasiexperimental design comparing patients admitted in the two study periods. Prior to each of the study periods, daylight and the contribution from the LED-lighting scenarios was measured. Patient sociodemographic and mental health data will be retrieved retrospectively from electronic medical records and by questionnaires administered in the two periods, evaluating lighting, noise, sleep quality and quality of life. Primary outcome is the proportion of patients receiving pro re nata medications. Secondary outcomes are the length of stay, sleep onset latency, sleep quality and quality of life., Ethics and Dissemination: No ethical issues are expected. The results will be disseminated through peer-reviewed international journal, lectures, posters and interviews., Trial Registration Number: NCT05868291., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Seasonality in depressive and bipolar disorders, are recognized in the ICD-10/11 and DSM-5 diagnostic systems. The existence of a seasonal pattern of hospital diagnosis of major depression, bipolar disorder and prescription of antidepressant medications has not been evaluated in the Danish population., Methods: We retrieved date and year for all first-time hospital contacts with depression or bipolar disorder between 1999 and 2019, registered in the Danish National Patient Registry. Depression was defined using the ICD-10 F32-F33 codes, and for bipolar disorder the F30 or F31 codes. Date and year of all first-time purchases of antidepressant medications with ATC codes (N06A) between 1999 and 2021 were retrieved from the Danish National Prescription Registry, containing information on all prescribed drugs dispensed at pharmacies since 1995. Data on sunlight hours from 2012 to 2021 were retrieved from the Danish Metrological Institute., Results: Incidences of hospital diagnoses as well as purchases of medication varied with month and season. The monthly variations were larger for antidepressant medication and smallest for bipolar disorder. The multiple linear regression analysis showed that number of first-time diagnoses of depression or bipolar disorder did not correlate with season. For antidepressant medication the number of first-time prescriptions was significantly lower in summer compared to the winter season., Conclusion: This study found a seasonal variation of first-time prescriptions of antidepressant medication. We did not find a seasonal variation in first-time hospital diagnoses. Further research looking into depression severity, polarity of bipolar illness episodes, lag-time for sunlight exposure, and specific parts of the yearly photoperiods should be conducted.

Introduction: This study investigated the health effects of two different architectural glass types: A two-layered low-iron high transmittance glass and a three-layered low energy glass with lower transmittance. The study investigated how these glass types affected daylight conditions in 72 residential apartments, as well as health and satisfaction of the residents. Methods: The study installed high transmittance glass (light transmittance LT:0.82) in 36 apartments and low transmittance (LT:0.74) in 36 identical apartments. The study then analyzed the light transmittance of each glass type in the laboratory and analyzed the indoor environmental quality (IEQ) in eight representative apartments before and after renovation. Self-reported questionnaires were handed out and collected before and after renovation. Results: The results showed that the glass types differed significantly in measured daylight transmittance. The two-layered high transmittance glass transmitted 15% more visual light (380-750 nm) and 20% more light in the spectral range (460-480 nm), stimulating ipRGCs and circadian rhythm, when compared to three-layered low energy glass. In addition, significant differences were observed in the UV-B spectrum (280-315 nm). While two-layered high transmittance glass transmitted UV-B, three-layered low transmittance glass did not. During the 12-month study period, residents in apartments with three-layered low energy glass reported more difficulties sleeping ( p  = 0.05), higher satisfaction with daylight ( p  = 0.03) and higher satisfaction with ventilation ( p  = 0.04). Residents in apartments with three-layered low energy glass experienced fewer days with too cold indoor temperatures ( p  = 0.02), compared to residents with two-layered low-iron glass. The results of energy consumption for heating showed that two-layered low-iron glass reduced the energy consumption by 11.0%, while three-layered low energy glass reduced the energy consumption by 9.4%, compared to the year prior to renovation. Conclusion: The results contribute to a discussion about potential energy savings on one hand and potential non-energy benefits, such as daylight quality, overall health, and total economy/life cycle assessment of the built environment on the other hand. The results suggest further research performed in randomized large-scale studies.

Background: In many Danish schools, the indoor environmental quality (IEQ) is challenged and studies document a poor IEQ in a majority of existing schools. Municipalities cannot afford comprehensive renovations and expensive mechanical ventilation solutions, hence public schools often suffer from poor indoor environment conditions. This study tests a new façade based, demand-controlled ventilation solution called NOTECH in the renovation of school. The study tests NOTECH vs. existing mechanical ventilation solution, comparing performance of both solutions at Skovbrynet Skole in Denmark., Methods: The project investigates the effect of the NOTECH solution in a primary school classroom, comparing it to a similar classroom with conventional, mechanical ventilation. Methodically, indoor environmental quality and energy performance is monitored in the two identical classrooms during one school year 2018 - 2019., Results: The results show that both systems keep the conditions within acceptable limits and CO2 levels below 1000 ppm, which is the requirement according to the Danish Building Regulations. In terms of costs, the NOTECH system has a lower overall cost than the mechanical ventilation system, with total estimated costs for installation, heating, electricity and maintenance amounting to approximately 35% of the mechanical system's costs. Finally, the results show that the NOTECH solution has a smaller embedded CO2 footprint for building materials, reducing the estimated carbon load by 95% compared to the mechanical ventilation solution., Conclusions: While the performance of the both systems complies to the Danish Building Regulations, the indoor environmental quality between systems differs significantly. Results showing a higher air-temperature and lower relative air-humidity in the classroom with mechanical ventilation during winter and lower CO 2 levels in the mechanically ventilated classroom during winter and summer. Costs for implementation, energy consumption for heating and CO 2 footprint for building materials are significantly lower for the NOTECH solution, compared to the mechanical solution., Competing Interests: Competing interests: The system in the study was tested and developed in an independent research project at Skovbrynet Skole. Later on, the NOTECH solution was further improved and the authors C Volf together with Danish Techno-logical Institute (DTI) implemented it at a new school project and won a Danish Design Award 2021 in the category Better Learning. In this process and in the later development of the system, WindowMaster was a commercial part. The timeline for this development process and the study is independent, and data and conclusions only refer to the study at Skovbrynet Skole., (Copyright: © 2024 Volf C et al.)

Introduction: Retrospective studies conducted in psychiatric inpatient wards have shown a relation between the intensity of daylight in patient rooms and the length of stay, pointing to an antidepressant effect of ambient lighting conditions. Light therapy has shown a promising antidepressant effect when administered from a light box. The emergence of light-emitting diode (LED) technology has made it possible to build luminaires into rooms and to dynamically mimic the spectral and temporal distribution of daylight. The objective of this study is to investigate the antidepressant efficacy of a newly developed dynamic LED-lighting system installed in an inpatient ward., Methods and Analysis: In all, 150 inpatients with a major depressive episode, as part of either a major depressive disorder or as part of a bipolar disorder, will be included. The design is a two-arm 1:1 randomised study with a dynamic LED-lighting arm and a static LED-lighting arm, both as add-on to usual treatment in an inpatient psychiatric ward. The primary outcome is the baseline adjusted score on the 6-item Hamilton Depression Rating Scale at week 3. The secondary outcomes are the mean score on the Suicidal Ideation Attributes Scale at week 3, the mean score on the 17-item Hamilton Depression Rating Scale at week 3 and the mean score on the World Health Organisation Quality of Life-BREF (WHOQOL-BREF) at week 3. The spectral distribution of daylight and LED-light, with a specific focus on light mediated through the intrinsically photosensitive retinal ganglion cells, will be measured. Use of light luminaires will be logged. Assessors of Hamilton Depression Rating Scale scores and data analysts will be blinded for treatment allocation. The study was initiated in May 2019 and will end in December 2021., Ethics and Dissemination: No ethical issues are expected. Results will be published in peer-reviewed journals, disseminated electronically and in print and presented at symposia., Trial Registration Number: NCT03821506; Pre-results., Competing Interests: Competing interests: TSH is an employee of Chromaviso that has supplied the lighting system., (© Author(s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Retrospective studies conducted in psychiatric wards have indicated a shorter duration of stay for depressed inpatients in bright compared to dim daylight-exposed rooms, pointing to a possible antidepressant effect of daylight conditions. Dynamic LED lighting, aiming to mimic daylight conditions, are currently been installed in several hospitals, but their feasibility is poorly investigated., Methods: To investigate the feasibility of these systems, we developed and installed a LED-lighting system in four rooms in a psychiatric inpatient ward. The system could function statically or dynamically regarding light intensity and colour temperature. The system consisted of (A) a large LED luminaire built into the window jamb mimicking sunlight reflections, (B) two LED light luminaires in the ceiling and (C) a LED reading luminaire. In the static mode, the systems provided constant light from A and B. In the dynamic mode, the system changed light intensity and colour temperature using A, B and C. Patients with unipolar or bipolar depression were randomised to dynamic or static LED lighting for 4 weeks, in addition to standard treatment. Primary outcome was the rate of patients discontinuing the trial due to discomfort from the lighting condition. Secondary outcomes were recruitment and dropout rates, visual comfort, depressive symptoms and suicidal ideation., Results: No participants discontinued due to discomfort from the LED lighting. Recruitment rate was 39.8%, dropout from treatment rates were 56.3% in the dynamic group and 33.3% in the static group. 78.1% in the dynamic group were satisfied with the lighting compared with 71.8% in the static group. Discomfort from the light (glare) was reported by 11.5% in the dynamic group compared to 5.1% in the static group. Endpoint suicidal scores were 16.8 (10.4) in the dynamic and 16.3 (14.9) in the static group. The lighting system was 100% functional. The light sensor system proved unstable., Conclusion: Dropout from treatment was high primarily due to early discharge and with a lack of endpoint assessments. The feasibility study has influenced an upcoming large-scale dynamic lighting efficacy trial where we will use a shorter study period of 3 weeks and with more emphasis on endpoint assessments. The lighting was well tolerated in both groups, but some found intensity too low in the evening. Thus, we will use higher intensity blue-enriched light in the morning and higher intensity amber (blue-depleted) light in the evening in the upcoming study. The light sensor system needs to be improved., Trial Registration: ClinicalTrials.gov: NCT03363529., Competing Interests: Competing interestsTSH is an employee of Chromaviso that has supplied the lighting system. The other authors declare that they have no competing interests., (© The Author(s). 2020.)

Background and Aim: Improvement in patients admitted to inpatient wards with severe depression is slow, and such patients are often discharged with residual symptoms which put them at risk for relapse. New treatments that can speed up recovery are highly desired. This naturalistic follow-up study in a specialized affective disorders unit investigated the impact of daylight on the length of hospital stay and improvement of depression., Methods: For a period of 1 year, we collected data on sociodemographics, length of stay, vitamin D, and depression severity for patients in an inpatient affective disorders unit. The ward is located with one facade that faces southeast (SE); the opposite one faces northwest (NW) and receives far less light and no direct sunlight during winter., Results: SE-facing rooms received far more daylight than NW-facing rooms. The length of stay was significantly lower in the SE rooms, i.e., 29.2 (±26.8) versus 58.8 (±42.0) days in the NW rooms (p = 0.01). There was a statistically nonsignificant greater reduction of 52.2% in depression severity for the patients staying in the SE rooms compared to 42.2% in the NW rooms, which may nevertheless be clinically relevant., Conclusion: Due to the study design, no causality for the observed difference in length of stay can be given, but the results support findings in previous studies of the importance of architectural orientation providing natural daylight as a factor for improvement., (© 2017 S. Karger AG, Basel.)