A Quantitative General Population Job Exposure Matrix for Occupational Daytime Light Exposure.

Introduction: Light is the strongest zeitgeber (time cue) for the human central circadian clock, and its effects on health may vary depending on the time of day by either strengthening or dampening circadian rhythms. However, the relations between various light exposures and human health remain largely unknown, partly due to the lack of available measurements. Hypothesis: We hypothesized that greater nighttime and evening light exposure would be associated with a higher mortality risk, while greater daytime light exposure would be associated with a lower mortality risk. Methods: This population-based prospective cohort study included 7,909 participants aged ≥20 years, with ≥4 days of data from wrist-worn accelerometers with light sensors measuring ambient light (lux) at 1 Hz from the U.S National Health and Nutrition Examination Survey 2011-2014. Mortality data through 2019 were obtained via linkage to the National Death Index. The average intensity of ambient light exposure during daytime (6:00 AM-7:59 PM), evening (8:00-11:59 PM), and nighttime (0:00-5:59 AM) were calculated. Cox models were used to estimate hazard ratios (HRs) for mortality. Results: During a median (IQR) follow-up of 6.8 (5.7-7.8) years, 803 deaths were documented, including 255 from cardiovascular disease and 192 from cancer. The multivariable-adjusted HRs (95% CIs) for all-cause mortality were 0.82 (0.66-1.03) for the second quartile of daytime light exposure, 0.83 (0.67-1.04) for the third quartile, and 0.67 (0.51-0. 89) for the highest quartile, compared to the lowest quartile ( P for trend <0.001). Conversely, there was no association between nighttime ( P for trend = 0.14; HR for the highest vs lowest quartile: 0.94 [0.75-1.19]) or evening light exposure ( P for trend = 0.46; HR for the highest vs lowest quartile: 0.85 [0.71-1.03]) and all-cause mortality risk. Similar inverse associations of daytime light exposure were observed for cardiovascular disease mortality ( P for trend = 0.04; HR for highest vs lowest quartile: 0.65 [0.36-1.20]) but not for cancer mortality ( P for trend = 0.27; HR for highest vs lowest quartile: 0.89 [0.54-1.48]). Conclusions: In this nationally representative sample of U.S. adults, greater objectively measured ambient light exposure during daytime was inversely associated with all-cause and cardiovascular disease mortality risk. These findings may have significant public health implications given the reduced exposure to daytime light in modern society.

IntroductionHigher winter depression prevalence at temperate latitudes has been attributed to low daylight levels. Daytime light exposure varies across jobs.ObjectivesIn a nationwide study, we examined occupational daytime light exposure levels...

Outdoor workers are exposed to high levels of solar ultraviolet radiation (UVR). UVR causes skin cancer and is a risk factor for cataract and other short- and long-term health effects, but there are significant knowledge gaps regarding the exposure-response relations based on quantitative measures of UVR exposure. We developed a quantitative UVR job-exposure matrix (JEM) for the general working population of Europe. Three experts from each of Northern, Central, and Southern Europe rated duration of outdoor work for all 372 occupations defined by the International Standard Classification of Occupations from 1988 (ISCO-88(COM)). A systematic literature search identified 12 studies providing 223 sets of summary workday UVR exposure for 49 ISCO-88(COM) occupations based on 75,711 personal workday measurements obtained from 2,645 participants and reported as arithmetic mean standard erythemal dose (SED). We combined the expert ratings with the measured occupational UVR exposure data and estimated harmonized workday UVR exposures for all 372 occupations in a linear mixed effects model. Monotonically increasing workday UVR exposure of 0.68, 1.57, 1.80, and 2.49 SED were seen by increasing expert ratings of 0, 1 to 2, 3 to 4, and ≥5 h of daily outdoor work. The UVR exposure showed a 6-fold increase from lowest to highest exposed occupation. Farm hands, roofers, concrete placers, and other occupations within craft and related trades were among the highest exposed, while bartenders, wood-processing-plant operators, and several white-collar occupations who typically work indoor were among the lowest exposed. This quantitative JEM for solar UVR exposure proves able to provide substantial discrimination between occupations, shows good agreement with expert assessments, and may facilitate epidemiological studies characterizing the exposure-response relation between occupational solar UVR exposure and different health effects.

IntroductionLight has powerful effects on mood, sleep, and the circadian system. Humans evolved in an environment with a clear distinction between day and night, but our modern lighting environments have blurred this distinction. While the disruptive effects of night time light exposure are well described, the potential positive effects of daytime light exposure on these systems are less well studied.MethodParticipants were a subset of the UK Biobank cohort who were invited to complete a seven day wrist-worn actimetry and light sensor study (n = 8,372, 61% female, age range: 39–70). Hierarchical linear models assessed the association between average daytime light exposure and mood-, sleep- and circadian-related outcomes, adjusted for age, sex, and season of assessment.ResultsGreater daytime light exposure was associated with earlier chronotype (p < .001), greater ease of getting up in the morning (p < .001), lower odds of using antidepressant medication (p < .001), less frequent low-mood (p = .002), less frequent anhedonia (p < .001), greater happiness (p < .001), less frequent insomnia symptoms (p = .01) and less frequent tiredness (p < .001).ConclusionsIn the largest study to-date, we observe that greater daytime light predicts better outcomes across a range of mood-, sleep- and circadian-related measures. Our findings are consistent with the known effects of light on the circadian system, whereby greater daytime light enhances the strength of the rhythm allowing for greater distinction between sleep and wake states. These findings

Systemic autoimmune rheumatic diseases (SARDs) develop in genetically susceptible individuals when exposed to environmental factors such as respirable crystalline silica (RCS) particles. Assessing occupational exposure in population-based studies is critical but resource intensive, often requiring expert interviews. This study aimed to develop and validate a self-administered occupational history questionnaire that allows for International Standard Classification of Occupations 1968 (ISCO-68) coding and exposure assessment as a cost-effective alternative to traditional interviews. Seventy RA patients participated by completing a standardized telephone interview and the newly developed self-administered questionnaire. Participants were also asked to recruit two gender- and age-matched family members for comparison. Independent observers assigned ISCO-68 codes to the reported jobs and a job exposure matrix was used to link each job to RCS exposure. Agreement between the interview and questionnaire was assessed by comparing reported working years, ISCO-68 job codes and RCS exposure. Cohen's κ and intraclass correlation were calculated to evaluate agreement and interobserver variability. The patient response rate was 77%, but family member controls had a low response rate (6.45%), likely impacted by the COVID-19 pandemic. Agreement for reported working years was 91%, with a Cohen's κ of 0.87 for ever/never RCS exposure. Manual ISCO coding introduced variability, but interobserver reliability remained high (intraclass correlation coefficient = 0.91). The self-administered occupational history questionnaire provides a valid, cost-effective and time-efficient alternative to telephone interviews for assessing occupational history and estimating RCS exposure in epidemiological research. Future studies should explore automated coding systems and improved strategies for control recruitment.

Light intensity and suppression of nocturnal plasma melatonin in Arctic charr (Salvelinus alpinus)

In this study, an experiment was conducted to suggest optimal daytime temperature and light intensity for cucumber scion and rootstock production in a plant factory with artificial light. Plant growth of cucumber scions and rootstocks at a day/night temperature of 26/18 °C and photosynthetic photon fluxes of 50, 120, 190, 260, 330, and 400 μmol·m−2·s−1 was investigated. Plant growth under daytime temperatures of 25/18, 26/18, 27/18, and 28/18 °C at a photosynthetic photon flux of 260 μmol·m−2·s−1 was investigated. As the photosynthetic photon flux increased, hypocotyl length was shortened in cucumber scions and rootstocks, but Dickson quality index, compactness, and Seedling Health Index were improved. As the daytime temperature increased, the hypocotyl length of cucumber scions increased, but the quality of seedlings decreased. The root growth of scions decreased as the daytime temperature increased. As for the correlation between the major growth indicators, Dickson quality index, compactness, and Seedling Health Index showed a high correlation of more than 0.8 in stem diameter, leaf, and root weight. Therefore, it is judged that it is most efficient to maintain the photosynthetic photon flux at 260 μmol·m−2·s−1 throughout the year and adjust the daytime temperature to 25 to 28 °C according to the season for farms and commercial nurseries that produce cucumber seedlings by installing plant factories with artificial light.

Background In Switzerland, surgical resident training has become increasingly difficult over the past decades for numerous reasons. While the number of surgical residents has doubled over twenty years, the average workweek dropped from 70 to 50 hours. At the same time, the surgical caseload increased only marginally as opposed to the proportion of administrative responsibilities, resulting in a substantial decrease of intraoperative exposure in surgical residency training. Aims To assess the surgical exposure of our residents. Methods This study is a review of all performed surgical procedures in the field of general, abdominal, thoracic, vascular and trauma surgery at a category-A Cantonal hospital in Switzerland, performed from September 1st 2021 to August, 31st 2023. The primary outcome was surgical exposure of residents as primary, secondary, and assisting surgeons. Secondary outcomes were case-distribution during daytime workhours as opposed to on-call hours per resident. Results The surgical exposure of a surgical resident at our cantonal hospital as primary and secondary surgeon was 41.19 and 39.06 minutes respectively per week. This surgical exposure as was paired with a total of 127.46 minutes as assisting surgeons per week. On average this results in 1.34 operations per week and 60.3 cases per year per surgical resident. 73.51% of these cases are performed during daytime work hours and 26.49% during on-call hours. Conclusion To fulfill the minimal number of 510 cases in the mandatory FMH surgical catalogue of becoming a general surgeon, a total residency period of 8.46 years would become necessary to take the exam based on the average number of operative cases in this category-A teaching hospital which is considerably longer compared to residency training 20 years ago. While surgical procedures and techniques continue to become more complex, the need to exploit ways to maintain a sufficient level of surgical exposure inside and outside the OR is eminent.

The neuropeptide orexin/hypocretin is implicated in sleep and arousal, energy expenditure, reward, affective state and cognition. Our previous work using diurnal Nile grass rats (Arvicanthis niloticus) found that orexin mediates the effects of environmental light, particularly daytime light intensity, on affective and cognitive behaviours. The present study further investigated how daytime light intensity affects the central orexin system in male and female grass rats. Subjects were housed for 4weeks in 12:12hr dim light:dark (50 lux, dimLD) or in 12:12hr bright light:dark cycle (1000 lux, brightLD). Day/night fluctuations in some orexin measures were also assessed. Despite similar hypothalamic prepro-orexin mRNA expression across all conditions, there were significantly more orexin-immunoreactive neurons, larger somata, greater optical density or higher orexin A content at night (ZT14) than during the day (ZT2), and/or in animals housed in brightLD compared to dimLD. Grass rats in brightLD also had higher cisternal CSF levels of orexin A. Furthermore, orexin receptor OX1R and OX2R proteins in the medial prefrontal cortex were higher in brightLD than dimLD males, but lower in brightLD than dimLD females. In the CA1 and dorsal raphe nucleus, females had higher OX1R than males without any significant effects of light condition, and OX2R levels were unaffected by sex or light. These results reveal that daytime light intensity alters the central orexin system of both male and female diurnal grass rats, sometimes sex-specifically, and provides insight into the mechanisms underlying how daytime light intensity impacts orexin-regulated functions.

The circadian response is sensitive to visible short wavelengths. With the conversion of streetlighting to LEDs that have a greater short wavelength spectrum than traditional sources, there could be a potential negative health impact through influencing the biological clock of drivers. This paper provides maximum values of melanopic EDI (Equivalent Daylight Illuminance) of drivers using standard streetlighting calculation tools. It also evaluates the circadian impact on drivers under typical usage pattern using thresholds from a comprehensive consensus view which has been published recently about “Recommendations for daytime, evening, and nighttime light exposure to best support physiology, sleep, and wakefulness in healthy adults” (BROWN, T.M. at all, 2022). Results show: If a streetlighting respects recommendations of relevant CIE publications about visual performance, especially glare restrictions, the light exposure provided by streetlighting has no significant negative effect on circadian behaviour of drivers. This statement is in line with field measurements by others.

The relations between chronotype, stressful life events, and impulsivity in the Adolescent Brain Cognitive Development (ABCD) study

In addition to classical visual effects, light elicits nonvisual brain responses, which profoundly influence physiology and behavior. These effects are mediated in part by melanopsin-expressing light-sensitive ganglion cells that, in contrast to the classical photopic system that is maximally sensitive to green light (550 nm), is very sensitive to blue light (470-480 nm). At present, there is no evidence that blue light exposure is effective in modulating nonvisual brain activity related to complex cognitive tasks. Using functional magnetic resonance imaging, we show that, while participants perform an auditory working memory task, a short (18 min) daytime exposure to blue (470 nm) or green (550 nm) monochromatic light (3 x 10(13) photons/cm2/s) differentially modulates regional brain responses. Blue light typically enhanced brain responses or at least prevented the decline otherwise observed following green light exposure in frontal and parietal cortices implicated in working memory, and in the thalamus involved in the modulation of cognition by arousal. Our results imply that monochromatic light can affect cognitive functions almost instantaneously and suggest that these effects are mediated by a melanopsin-based photoreceptor system.

Light intensity is a critical variable of the dye-sensitized photooxidation reaction, and the rate of house fly, Musca domestica , mortality is observed to increase with increasing light intensity. Relative toxicities were described for 6 xanthene dyes (rose bengal, octabromofluorescein, erythrosin B, phloxin B, eosin Y, and tetrachlorofluorescein) as a function of the 3rd-order rate constant of photooxidation, k3, obtained for each dye and determined from the LT50, tissue dye levels, and light intensity measurements. The ranking of these 6 xanthenes by their respective k3 values is almost identical to the ranking of these same dyes by their k2, or second-order rate constant. The number of accumulated photons needed to produce 50% mortality was observed to decrease with an increase in light intensity.

ObjectiveTo examine the association of adult onset asthma with lifetime exposure to occupations and occupational exposures.MethodsWe generated lifetime occupational histories for 9488 members of the British 1958 birth cohort up...

The main risk factor for bladder cancer (BC) is cigarette smoking, but also occupational exposure to carcinogens is relevant, causing about 4-10% of BC. We aimed at investigating the association between BC risk, occupations held in the past and exposure to occupational carcinogens, also assessing whether these associations were influenced by tumour grade. We pooled data from two Italian case-control studies on male BC, analyzing 893 cases and 978 controls. Occupations were classified using the International Standard Classification of Occupations and exposure to carcinogens was assigned using a validated Job Exposure Matrix. Logistic regression approach was used as well as a semi-Bayesian model, based on a priori information on exposure. A significantly increased BC risk was found for chemical engineering technicians, postmen, and lathe operators, but only, for the latter, the association remained significant after Bayesian control for type I error. Among carcinogens, cadmium and trichloroethylene were associated with BC. When analyzing data by grade, exposure to these carcinogens was associated with low-grade BC only. Our results suggest that monitoring workplaces to prevent exposure to carcinogenic agents is still an important task, which should be still given adequate importance in public health.