Light pollution inequities in the continental United States: A distributive environmental justice analysis

Sociodemographic inequalities in residential nighttime light pollution in urban Bulgaria: An environmental justice analysis

INTRODUCTION

Outdoor nighttime light (NTL) is a potential anthropogenic stressor in urban settings. While ecological studies have identified outdoor NTL exposure disparities, uncertainties remain about disparities in individual exposure levels, particularly in Europe.

AIM

To assess whether some populations are disproportionately affected by outdoor NTL at their residences in urban Bulgaria.

METHODS

We analyzed 2023 data from a representative cross-sectional survey of 4,270 adults from the five largest Bulgarian cities. Respondents' annual exposures to outdoor artificial nighttime luminance were measured using satellite imagery and assigned at their places of residence. We calculated the Gini coefficient as a descriptive NTL inequality measure. Associations between respondents' NTL exposure levels and sociodemographic characteristics were assessed by estimating quantile mixed regression models. Stratified regressions were fitted by gender and for each city.

RESULTS

We found moderate distributive NTL inequalities, as indicated by a 0.214 Gini coefficient. Regression analyses found associations between greater NTL exposure and higher educational attainment. Respondents with incomes perceived as moderate experienced less NTL exposure at the 0.5 and 0.8 quantiles, while unemployed respondents experienced lower exposure at the 0.2 and 0.5 quantiles. We observed null associations for the elderly and non-Bulgarian ethnicities. Regardless of the quantile, greater population density was associated with higher NTL levels. Stratification by sex did not yield substantial differences in the associations. We observed notable city-specific heterogeneities in the associations, with differences in the magnitudes and directions of the associations and the NTL quantiles.

CONCLUSIONS

NTL exposures appeared to embody an environmental injustice dimension in Bulgaria. Our findings suggest that some sociodemographic populations experience higher exposure levels to NTL; however, those are not necessarily the underprivileged or marginalized. Identifying populations with high exposure levels is critical to influencing lighting policies to ease related health implications.

The effect of residential greenness on cardiovascular mortality from a large cohort in South China: An in-depth analysis of effect modification by multiple demographic and lifestyle characteristics

BACKGROUND

The potential for residential greenness to improve cardiovascular health through both physical and psychological mechanisms is well recognized. However, evidence from rapidly urbanizing developing countries and cohort-based causal inference approaches, remains limited. We aim to examine the effect of residential greenness and time to cardiovascular mortality in South China.

METHODS

We utilized data from a community-based population survey involving 748,209 participants at baseline from 2009 to 2015, followed up until 2020. Residential greenness exposure was assessed by the annual Normalized Difference Vegetation Index (NDVI) in the 500 m radius of each participant's residence. We used time-varying proportional hazard Cox models coupled with inverse probability weighting to fit marginal structural models and obtain hazard ratios (HRs) for cardiovascular disease (CVD) mortality after adjusting for confounders. Multiple effect modifiers on both additive and multiplicative scales were further explored.

RESULTS

A total of 15,139 CVD-related deaths were identified during a median of 7.9 years of follow-up. A protective effect was found between higher greenness exposure and reduced CVD mortality, with a 9.3 % lower rate of total CVD mortality (HR 0.907, 95 % CI 0.859-0.957) based on a 0.1 increase in annual average NDVI. Demographic (age, marital status) and lifestyle factors (smoking, drinking status) were found to modify the association between residential greenness and CVD mortality (all P interaction values < 0.05 or 95 %CI for RERI excluded the value 0). Notably, this effect was more pronounced among older adults, married, and individuals having healthier lifestyles, indicating a greater benefit from greenness for these subgroups.

CONCLUSIONS

Our findings support a causal link between increased residential greenness exposure and a reduced risk of CVD mortality in South China with marked heterogenous effects, which has public health implications for cultivating greener urban environments to mitigate the impact of CVD within the context of rapid urbanization.

Environmental noise is positively associated with socioeconomically less privileged neighborhoods in the Netherlands

BACKGROUND

Environmental noise has detrimental effects on various health outcomes. Although disparities in some environmental exposures (e.g., air pollution) are well-documented, there is still a limited and uncertain understanding of the extent to which specific populations are disproportionately burdened by noise.

AIM

To assess whether environmental noise levels are associated with demographic and socioeconomic neighborhood compositions.

METHODS

We cross-sectionally examined long-term noise levels for 9,372 neighborhoods in the Netherlands. We linked these noise levels with administrative data on neighborhood characteristics for the year 2021. Linear and non-linear spatial regression models were fitted to explore the associations between noise, demographic, and socioeconomic neighborhood characteristics.

RESULTS

Our results showed that 46 % of the neighborhoods exhibited noise levels surpassing the recommended threshold of 53 dB to prevent adverse health effects. The regressions uncovered positive and partially non-linear neighborhood-level associations between noise and non-Western migrants, employment rates, low-incomers, and address density. Conversely, we found negative associations with higher-educated neighborhoods and those with a greater proportion of younger residents. Neighborhoods with older populations displayed a U-shaped association.

CONCLUSIONS

This national study showed an inequality in the noise burden, adversely affecting vulnerable, marginalized, and less privileged neighborhoods. Addressing the uneven distribution of noise and its root causes is an urgent policy imperative for sustainable Dutch cities.

Neighborhood Light at Night and Noise Levels, and Long-Term Sleep Trajectories in the Southern Community Cohort Study

While light at night (LAN) and noise levels have been linked to suboptimal sleep outcomes, little is known about the link between these factors and long-term suboptimal sleep trajectories. The current study examined the association of neighborhood LAN and nighttime noise with long-term sleep trajectories in a cohort of Black individuals and White individuals predominantly from low-income communities. We used data from the Southern Community Cohort Study (N = 28,759 Black individuals and 16,276 White individuals). Sleep duration was self-reported at baseline and after an average of five years of follow-up, based on which we constructed nine sleep trajectories: normal-normal (optimal, reference), short-short, long-long, short-long, long-short, normal-short, normal-long, short-normal, and long-normal. LAN and nighttime noise were derived from satellite imagery and model-based estimates, respectively. Multinomial logistic regression was used to determine the relationship between LAN and noise exposures and sleep trajectories. Higher exposures to LAN and nighttime noise were associated with multiple suboptimal long-term sleep trajectories. In the total sample, higher LAN was associated with higher odds of long-long (OR Q5 vs. Q1 = 1.23 (CI = 1.02, 1.48)) and long-short (OR = 1.35 (CI = 1.06, 1.72)) trajectories, while higher nighttime noise was associated with short-short (1.19 (1.07, 1.31)), long-short (1.31 (1.05, 1.64)), and normal-song (1.16 (1.01, 1.34)) trajectories. Black and White individual-specific results showed qualitatively similar patterns between Black individuals and White individuals, although we also observed suggestive evidence for Black-White individual differences. In conclusion, elevated LAN and nighttime noise levels were associated with various suboptimal long-term sleep trajectories. However, it is noteworthy that the light and noise measures in our study may not accurately reflect individual-level exposures, and residual confounding from other factors is a concern. Future studies should use more accurate exposure measurements, collect information on and control for a wider range of factors, and examine whether reductions in neighborhood light and noise levels may contribute to improved long-term sleep health.

Eyes Wide Open: Sleep as a Potential Contributor to Racial and Ethnic Disparities in Cancer

U.S. racial and ethnic minoritized groups face disproportionate cancer burdens compared to White Americans. Investigating modifiable factors, such as sleep, that are socially patterned and inequitably distributed by race and ethnicity may advance understanding of cancer disparities and provide intervention opportunities. Emerging data suggest poor sleep health is associated with cancer. Yet, its contribution to racial and ethnic cancer disparities is understudied. In this narrative review, we explored the sleep-cancer relation through a disparities lens. We (i) summarized literature reporting on associations between sleep and cancer among racial and ethnic minority populations; (ii) examined potential sleep-cancer mechanisms; and (iii) discussed future directions. We identified five studies reporting on sleep-cancer associations among minoritized groups. Poor sleep health was associated with aggressive breast cancer among Black women, increased breast cancer risk among Asian women, and increased risk of breast and total cancer among Hispanic/Latinx Americans. Sleep and cancer disparities have similar socioeconomic and behavioral determinants, suggesting racial and ethnic minoritized groups may be vulnerable to poor sleep health and its adverse health impacts. Evidence indicates that the sleep-cancer disparities relation is an emerging, but important area of research that warrants further investigation, as sleep may be an avenue for reducing cancer disparities.

Light exposure during sleep is bidirectionally associated with irregular sleep timing: The multi-ethnic study of atherosclerosis (MESA)

Exposure to light at night (LAN) may influence sleep timing and regularity. Here, we test whether greater light exposure during sleep (LEDS) is bidirectionally associated with greater irregularity in sleep onset timing in a large cohort of older adults in cross-sectional and short-term longitudinal (days) analyses. Light exposure and activity patterns, measured via wrist-worn actigraphy (ActiWatch Spectrum), were analyzed in 1933 participants with 6+ valid days of data in the Multi-Ethnic Study of Atherosclerosis (MESA) Exam 5 Sleep Study. Summary measures of LEDS averaged across nights were evaluated in linear and logistic regression analyses to test the association with standard deviation (SD) in sleep onset timing (continuous variable) and irregular sleep onset timing (SD > 90 min, binary). Night-to-night associations between LEDS and absolute differences in nightly sleep onset timing were also evaluated with distributed lag non-linear models and mixed models. In between-individual linear and logistic models adjusted for demographic, health, and seasonal factors, every 5-lux unit increase in LEDS was associated with a 7.8-min increase in sleep onset SD (β = 0.13 h, 95%CI:0.09-0.17) and 32% greater odds (OR = 1.32, 95%CI:1.17-1.50) of irregular sleep onset. In within-individual night-to-night mixed model analyses, every 5-lux unit increase in LEDS the night prior was associated with a 2.2-min greater deviation of sleep onset the next night (β = 0.036 h, p < 0.05). Conversely, every 1-h increase in sleep deviation was associated with a 0.35-lux increase in future LEDS (β = 0.348 lux, p < 0.05). LEDS was associated with greater irregularity in sleep onset in between-individual analyses and subsequent deviation in sleep timing in within-individual analyses, supporting a role for LEDS in irregular sleep onset timing. Greater deviation in sleep onset was also associated with greater future LEDS, suggesting a bidirectional relationship. Maintaining a dark sleeping environment and preventing LEDS may promote sleep regularity and following a regular sleep schedule may limit LEDS.

Addressing sleep deserts: A proposed call for action

Sleep deserts are a major cause of health inequity. They occur primarily in disadvantaged neighborhoods because of structural racism, social and environmental factors, and dearth of medical services. We describe several strategies that can serve as a feasible action plan to target structural racism, environmental pollution, and impact of climate change. We also suggest ways healthcare providers in these underserved areas can incorporate sleep medicine into their practice. Lastly, we highlight strategies to increase community awareness of sleep health in a culturally sensitive manner. There are several ways, from a policy level to healthcare that we can begin to eliminate sleep deserts, which is urgently needed.

Racial/ethnic and sex differences in the association between light at night and actigraphy-measured sleep duration in adults: NHANES 2011-2014

OBJECTIVE

Historically minoritized individuals experience greater exposure to light at night, yet it is unclear whether the association between light at night and sleep duration vary by race/ethnicity or sex. We examined the association between light at night and sleep duration by race/ethnicity and sex.

METHODS

Participants (N = 6089, mean age=49.5, 52% women, 13% Asian, 27% Black, 14% Mexican, 46% White) in the 2011-2014 National Health and Nutrition Examination Survey underwent 9-day of actigraphy. Light at night was defined as light exposure within the 5-hour activity nadir (L5). Sleep duration within a 24-hour period was analyzed as short (<7 hours) or long (>9 hours) compared to recommended (≥7 and <9 hours). Poisson models were fit to estimate the association between light at night and sleep duration after adjustment for covariates.

RESULTS

Light at night was most common among Black participants, who also had the shortest sleep duration. Overall, light at night was associated with 80% higher prevalence of short sleep duration [1.80 (1.49, 2.18)]. Compared to no-light at night, low and high light at night were associated with higher prevalence of short sleep duration, [1.61 (1.31, 1.98) and 2.01 (1.66, 2.44), respectively]. Associations varied by race/ethnicity and sex. Light at night was associated with shorter sleep duration in Black, Mexican and White females and Mexican and White males only. Black males exposed to light at night vs. no-light at night had lower prevalence of long sleep duration. There were no associations between light at night and sleep duration among Asian participants.

CONCLUSION

Light at night was associated with shorter sleep duration, particularly among females. Targeting light exposure may help to improve sleep duration.

County-level artificial light at night (ALAN) in the contiguous US (2012-2019): spatial variations, temporal trends, and environmental justice analyses

Artificial light at night (ALAN) is a growing environmental hazard with economic, ecological, and public health implications. Previous studies suggested a higher burden of light pollution and related adverse effects in disadvantaged communities. It is critical to characterize the geographic distribution and temporal trend of ALAN and identify associated demographic and socioeconomic factors at the population level to lay the foundation for environmental and public health monitoring and policy-making. We used satellite data from the Black Marble suite to characterize ALAN in all counties in contiguous US and reported considerable variations in ALAN spatiotemporal patterns between 2012 and 2019. As expected, ALAN levels were generally higher in metropolitan and coastal areas; however, several rural counties in Texas experienced remarkable increase in ALAN since 2012, while population-level ALAN burden also increased substantially in many metropolitan areas. Importantly, we found that during this period, although the overall ALAN levels in the USA declined modestly, the temporal trend of ALAN varied across areas with different racial/ethnic compositions: counties with a higher percentage of racial/ethnic minority groups, particularly Hispanic populations, exhibited significantly less decline. As a result, the differences in ALAN levels, as measured by the Black Marble product, across racial/ethnic groups became larger between 2012 and 2019. In conclusion, our study documented variations in ALAN spatiotemporal patterns across America and identified multiple population correlates of ALAN patterns that warrant further investigations. Future studies should identify underlying factors (e.g., economic development and decline, urban planning, and transition to newer lighting technologies such as light emitting diodes) that may have contributed to ALAN disparities in the USA.

Light exposure during sleep is associated with irregular sleep timing: the Multi-Ethnic Study of Atherosclerosis (MESA)

Objective

Exposure to light at night (LAN) may influence sleep timing and regularity. Here, we test whether greater light exposure during sleep (LEDS) associates with greater irregularity in sleep onset timing in a large cohort of older adults.

Methods

Light exposure and activity patterns, measured via wrist-worn actigraphy (ActiWatch Spectrum), were analyzed in 1,933 participants with 6+ valid days of data in the Multi-Ethnic Study of Atherosclerosis (MESA) Exam 5 Sleep Study. Summary measures of LEDS averaged across nights were evaluated in linear and logistic regression analyses to test the association with standard deviation (SD) in sleep onset timing (continuous variable) and irregular sleep onset timing (SD≥1.36 hours, binary). Night-to-night associations between LEDS and absolute differences in nightly sleep onset timing were also evaluated with distributed lag non-linear models and mixed models.

Results

In between-individual linear and logistic models adjusted for demographic, health, and seasonal factors, every 5-lux unit increase in LEDS was associated with an increase of 7.8 minutes in sleep onset SD (β=0.13 hours, 95%CI:0.09-0.17) and 40% greater odds (OR=1.40, 95%CI:1.24-1.60) of irregular sleep onset. In within-individual night-to-night mixed model analyses, every 5-lux unit increase in LEDS the night prior (lag0) was associated with a 2.2-minute greater deviation of sleep onset the next night (β=0.036 hours, p<0.05). Conversely, every 1-hour increase in sleep deviation (lag0) was associated with a 0.35-lux increase in future LEDS (β=0.347 lux, p<0.05).

Conclusion

LEDS was associated with greater irregularity in sleep onset in between-individual analyses and subsequent deviation in sleep timing in within-individual analyses, supporting a role for LEDS in exacerbating irregular sleep onset timing. Greater deviation in sleep onset was also associated with greater future LEDS, suggesting a bidirectional relationship. Maintaining a dark sleeping environment and preventing LEDS may promote sleep regularity and following a regular sleep schedule may limit LEDS.

Outdoor environmental exposome and the burden of tuberculosis: Findings from nearly two million adults in northwestern China

We simultaneously assessed the associations for a range of outdoor environmental exposures with prevalent tuberculosis (TB) cases in a population-based health program with 1940,622 participants ≥ 15 years of age. TB status was confirmed through bacteriological and clinical assessment. We measured 14 outdoor environmental exposures at residential addresses. An exposome-wide association study (ExWAS) approach was used to estimate cross-sectional associations between environmental exposures and prevalent TB, an adaptive elastic net model (AENET) was implemented to select important exposure(s), and the Extreme Gradient Boosting algorithm was subsequently applied to assess their relative importance. In ExWAS analysis, 12 exposures were significantly associated with prevalent TB. Eight of the exposures were selected as predictors by the AENET model: particulate matter ≤ 2.5 µm (odds ratio [OR]=1.01, p = 0.3295), nitrogen dioxide (OR=1.09, p < 0.0001), carbon monoxide (OR=1.19, p < 0.0001), and wind speed (OR=1.08, p < 0.0001) were positively associated with the odds of prevalent TB while sulfur dioxide (OR=0.95, p = 0.0017), altitude (OR=0.97, p < 0.0001), artificial light at night (OR=0.98, p = 0.0001), and proportion of forests, shrublands, and grasslands (OR=0.95, p < 0.0001) were negatively associated with the odds of prevalent TB. Air pollutants had higher relative importance than meteorological and geographical factors, and the outdoor environment collectively explained 11% of TB prevalence.

Association between Outdoor Light at Night and Prostate Cancer in the Health Professionals Follow-up Study

BACKGROUND

Circadian disruption is a potential risk factor for advanced prostate cancer, and light at night (LAN) exposure may disrupt circadian rhythms. We evaluated whether outdoor LAN increases the risk of prostate cancer.

METHODS

We prospectively followed 49,148 participants in the Health Professionals Follow-up Study from 1986 through 2016. We estimated baseline and cumulative time-varying outdoor LAN with ∼1 km2 resolution using data from the US Defense Meteorological Satellite Program's Operational Linescan System, which was assigned to participants' geocoded addresses. Participants reside in all 50 U.S. states and reported a work or home address. We used multivariable Cox models to estimate HRs and 95% confidence intervals (CI) for the association between outdoor LAN and risk of overall (7,175 cases) and fatal (915 cases) prostate cancer adjusting for individual and contextual factors.

RESULTS

There was no association between the interquartile range increase in cumulative LAN and total (HR, 1.02; 95% CI, 0.98-1.06) or fatal (HR, 1.05; 95% CI, 0.96-1.15) prostate cancer in adjusted models. However, there was a positive association between baseline LAN and total prostate cancer among non-movers (HR, 1.06; 95% CI, 1.00-1.14) including among highly screened participants (HR, 1.11; 95% CI, 1.01-1.23).

CONCLUSIONS

There was a suggestive positive association between baseline outdoor LAN and total prostate cancer. Additional studies with different measures of outdoor LAN and in more diverse populations are necessary.

IMPACT

To our knowledge, this is the first longitudinal cohort study exploring the relationship between outdoor LAN and prostate cancer.

Methods in Public Health Environmental Justice Research: a Scoping Review from 2018 to 2021

PURPOSE OF REVIEW

The volume of public health environmental justice (EJ) research produced by academic institutions increased through 2022. However, the methods used for evaluating EJ in exposure science and epidemiologic studies have not been catalogued. Here, we completed a scoping review of EJ studies published in 19 environmental science and epidemiologic journals from 2018 to 2021 to summarize research types, frameworks, and methods.

RECENT FINDINGS

We identified 402 articles that included populations with health disparities as a part of EJ research question and met other inclusion criteria. Most studies (60%) evaluated EJ questions related to socioeconomic status (SES) or race/ethnicity. EJ studies took place in 69 countries, led by the US (n = 246 [61%]). Only 50% of studies explicitly described a theoretical EJ framework in the background, methods, or discussion and just 10% explicitly stated a framework in all three sections. Among exposure studies, the most common area-level exposure was air pollution (40%), whereas chemicals predominated personal exposure studies (35%). Overall, the most common method used for exposure-only EJ analyses was main effect regression modeling (50%); for epidemiologic studies the most common method was effect modification (58%), where an analysis evaluated a health disparity variable as an effect modifier. Based on the results of this scoping review, current methods in public health EJ studies could be bolstered by integrating expertise from other fields (e.g., sociology), conducting community-based participatory research and intervention studies, and using more rigorous, theory-based, and solution-oriented statistical research methods.

The interactive effects of psychosocial stress and diet composition on health in primates

Social disadvantage and diet composition independently impact myriad dimensions of health. They are closely entwined, as social disadvantage often yields poor diet quality, and may interact to fuel differential health outcomes. This paper reviews effects of psychosocial stress and diet composition on health in nonhuman primates and their implications for aging and human health. We examined the effects of social subordination stress and Mediterranean versus Western diet on multiple systems. We report that psychosocial stress and Western diet have independent and additive adverse effects on hypothalamic-pituitary-adrenal and autonomic nervous system reactivity to psychological stressors, brain structure, and ovarian function. Compared to the Mediterranean diet, the Western diet resulted in accelerated aging, nonalcoholic fatty liver disease, insulin resistance, gut microbial changes associated with increased disease risk, neuroinflammation, neuroanatomical perturbations, anxiety, and social isolation. This comprehensive, multisystem investigation lays the foundation for future investigations of the mechanistic underpinnings of psychosocial stress and diet effects on health, and advances the promise of the Mediterranean diet as a therapeutic intervention on psychosocial stress.

Artificial light at night and social vulnerability: An environmental justice analysis in the U.S. 2012-2019

BACKGROUND

Artificial Light at Night (ALAN) is an emerging health risk factor that has been linked to a wide range of adverse health effects. Recent study suggested that disadvantaged neighborhoods may be exposed to higher levels of ALAN. Understanding how social disadvantage correlates with ALAN levels is essential for identifying the vulnerable populations and for informing lighting policy.

METHODS

We used satellite data from the National Aeronautics and Space Administration's (NASA) Black Marble data product to quantify annual ALAN levels (2012-2019), and the Center for Disease Control and Prevention's (CDC) Social Vulnerability Index (SVI) to quantify social disadvantage, both at the US census tract level. We examined the relationship between the ALAN and SVI (overall and domain-specific) in over 70,000 tracts in the Contiguous U.S., and investigated the heterogeneities in this relationship by the rural-urban status and US regions (i.e., Northeast, Midwest, South, West).

RESULTS

We found a significant positive relationship between SVI and ALAN levels. On average, the ALAN level in the top 20% most vulnerable communities was 2.46-fold higher than that in the 20% least vulnerable communities (beta coefficient (95% confidence interval) for log-transformed ALAN, 0.90 (0.88, 0.92)). Of the four SVI domains, minority and language status emerged as strong predictors of ALAN levels. Our stratified analysis showed considerable and complex heterogeneities across different rural-urban categories, with the association between greater vulnerability and higher ALAN primarily observed in urban cores and rural areas. We also found regional differences in the association between ALAN and both overall SVI and SVI domains.

CONCLUSIONS

Our study suggested ALAN as an environmental justice issue that may carry important public health implications. Funding National Aeronautics and Space Administration.

Disparities in greenspace associated with sleep duration among adolescent children in Southern California

More than half of adolescent children do not get the recommended 8 hours of sleep necessary for optimal growth and development. In adults, several studies have evaluated effects of urban stressors including lack of greenspace, air pollution, noise, nighttime light, and psychosocial stress on sleep duration. Little is known about these effects in adolescents, however, it is known that these exposures vary by socioeconomic status (SES). We evaluated the association between several environmental exposures and sleep in adolescent children in Southern California.

Methods

In 2010, a total of 1476 Southern California Children's Health Study (CHS) participants in grades 9 and 10 (mean age, 13.4 years; SD, 0.6) completed a questionnaire including topics on sleep and psychosocial stress. Exposures to greenspace, artificial light at night (ALAN), nighttime noise, and air pollution were estimated at each child's residential address, and SES was characterized by maternal education. Odds ratios and 95% confidence intervals (95% CIs) for sleep outcomes were estimated by environmental exposure, adjusting for age, sex, race/ethnicity, home secondhand smoke, and SES.

Results

An interquartile range (IQR) increase in greenspace decreased the odds of not sleeping at least 8 hours (odds ratio [OR], 0.86 [95% CI, 0.71, 1.05]). This association was significantly protective in low SES participants (OR, 0.77 [95% CI, 0.60, 0.98]) but not for those with high SES (OR, 1.16 [95%CI, 0.80, 1.70]), interaction P = 0.03. Stress mediated 18.4% of the association among low SES participants.

Conclusions

Residing in urban neighborhoods of greater greenness was associated with improved sleep duration among children of low SES but not higher SES. These findings support the importance of widely reported disparities in exposure and access to greenspace in socioeconomically disadvantaged populations.

Reducing nighttime light exposure in the urban environment to benefit human health and society

Nocturnal light pollution can have profound effects on humans and other organisms. Recent research indicates that nighttime outdoor lighting is increasing rapidly. Evidence from controlled laboratory studies demonstrates that nocturnal light exposure can strain the visual system, disrupt circadian physiology, suppress melatonin secretion, and impair sleep. There is a growing body of work pointing to adverse effects of outdoor lighting on human health, including the risk of chronic diseases, but this knowledge is in a more nascent stage. In this Review, we synthesize recent research on the context-specific factors and physiology relevant to nocturnal light exposure in relation to human health and society, identify critical areas for future research, and highlight recent policy steps and recommendations for mitigating light pollution in the urban environment.

"Dark under the lamp": ecological equity of urban agglomeration from the perspective of natural capital in China

Although equity is an important aspect of sustainable development, equity research has mainly focused on income and economics while paying insufficient attention to ecological equity. Therefore, aiming to improve our understanding of equity and promote environmental protection, this study introduced natural capital to measure regional ecological equity and analyze its driving factors. Based on ecological footprint (EF) and ecosystem service value (ESV), we constructed evaluation indexes and drew an "ecological Lorentz curve bundle" to analyze ecological equity in the Jing-Jin-Ji urban agglomeration (JUA) from 2009 to 2020. The results showed that economic development in JUA resulted in the severe depletion of natural capital, especially biological and energy resources, and the supply and demand of natural capital was in a low-level equilibrium state. Based on JUA's population base, natural capital utilization in the region had exceeded ecological equity, and the Gini coefficient of EF based on population was close to the international warning value of 0.4. Although economic development in JUA has promoted economic equity, it has also led to environmental inequity. Large cities such as Beijing and Tianjin, as well as industrial cities such as Tangshan and Handan, have had the greatest effects on ecological equity. Moreover, the excessive consumption of natural capital stock and energy-dependent industrial structures threaten ecological equity.

Differences in Sleep Offset Timing between Weekdays and Weekends in 79,161 Adult Participants in the UK Biobank

Variability in the timing of daily sleep is increasingly recognized as an important factor in sleep and general physical health. One potential driver of such daily variations in sleep timing is different work and social obligations during the "working week" and weekends. To investigate the nature of weekday/weekend differences in the timing of sleep offset, we examined actigraphy records of 79,161 adult participants in the UK Biobank who wore an actiwatch for 1 week. The time of sleep offset was found to be on average 36 min later on weekends than on weekdays, and when this difference was expressed as an absolute value (i.e., irrespective of sleep offset being either later or earlier on weekends), it was 63 min. Younger age, more socioeconomic disadvantage, currently being in employment, being a smoker, being male, being of non-white ethnicity and later chronotype were associated with greater differences in sleep offset between weekdays and weekend days. Greater differences in sleep offset timing were associated with age-independent small differences in cardiometabolic health indicators of BMI and diastolic blood pressure, but not HbA1c or systolic blood pressure. In a subset of participants with Type 2 Diabetes Mellitus, weekday/weekend sleep offset differences were associated weakly with BMI, systolic blood pressure and physical activity. Overall, this study demonstrates potentially substantive differences in sleep offset timings between weekdays and weekends in a large sample of UK adults, and that such differences may have public health implications.

Electric lighting, adolescent sleep and circadian outcomes, and recommendations for improving light health

Light is a potent circadian entraining agent. For many people, daily light exposure is fundamentally dysregulated with reduced light during the day and increased light into the late evening. This lighting schedule promotes chronic disruption to circadian physiology resulting in a myriad of impairments. Developmental changes in sleep-wake physiology suggest that such light exposure patterns may be particularly disruptive for adolescents and further compounded by lifestyle factors such as early school start times. This narrative review describes evidence that reduced light exposure during the school day delays the circadian clock, and longer exposure durations to light-emitting electronic devices in the evening suppress melatonin. While home lighting in the evening can suppress melatonin secretion and delay circadian phase, the patterning of light exposure across the day and evening can have moderating effects. Photic countermeasures may be flexibly and scalably implemented to support sleep-wake health; including manipulations of light intensity, spectra, duration and delivery modality across multiple contexts. An integrative approach addressing physiology, attitudes, and behaviors will support optimization of light-driven sleep-wake outcomes in adolescents.

Environmental inequity in hilly neighborhood using multi-source data from a health promotion view

The study focused on the justice of residents' opportunity to engage in healthy behavior under different environments is not vast, especially in a hilly dwelling environment. Therefore, this paper investigates environmental inequalities in a hilly urban environment in the context of the booming real estate market in China, comprised of health promotion-related elements, namely, built environment, physical activity facilities, street infrastructure, green spaces, and environmental perceptions. The multi-source data are used to calculate environmental attributes and the socioeconomic status of communities. We take the central districts of Dalian city as the research area and measure environmental equity across different socioeconomic residential areas using the Kruskal-Wallis one-way analysis of variance. The results reveal the spatial disparities in physical activity facilities, street greening, and positive perceptions between different communities. However, green injustice is mitigated in the hilly neighborhoods when we consider only ground-level greenness. This paper studies environmental justice by taking a health-enhancing view, and the results of this study can provide guidance on hilly urban development for government leaders and planners.

The lag effect of exposure to PM2.5 on esophageal cancer in urban-rural areas across China

Exposure to PM2.5 pollution is a significant health concern and increases risks for cancers in China. However, the studies regarding the effect of PM2.5 and esophageal cancer incidence (ECI) among urban-rural areas are limited. In this study, we examined the sex- and area-specific association between exposure to PM2.5 and ECI, as well as explored the corresponding lag effects on ECI using a geographical weighted Poisson regression. We found significantly positive effect on ECI for males and females in different models, with the greatest increase of 1.44% (95% CI: 1.30%, 1.59%) and 2.42% (95% CI: 2.17%, 2.66%) in per 10 ug/m3 increase of PM2.5 for males and females at single year lag7 and lag4 after all covariates controlled, respectively. We also found that the long-term effect of PM2.5 on ECI was relatively stable at all moving average year lags. Moreover, rural areas had higher ECI risks for males (0.17%) and females (0.64%) with longer lag period than urban areas. In addition, higher risks for both sexes appeared in north, northwestern, and east China. The findings indicated that long-term exposure to PM2.5 was significantly associated with increased risks for ECI, which reinforce a comprehensive understanding for ECI related to PM2.5.

Pervasive structural racism in environmental epidemiology

BACKGROUND

Epistemological biases in environmental epidemiology prevent the full understanding of how racism's societal impacts directly influence health outcomes. With the ability to focus on "place" and the totality of environmental exposures, environmental epidemiologists have an important opportunity to advance the field by proactively investigating the structural racist forces that drive disparities in health.

OBJECTIVE

This commentary illustrates how environmental epidemiology has ignored racism for too long. Some examples from environmental health and male infertility are used to illustrate how failing to address racism neglects the health of entire populations.

DISCUSSION

While research on environmental justice has attended to the structural sources of environmental racism, this work has not been fully integrated into the mainstream of environmental epidemiology. Epidemiology's dominant paradigm that reduces race to a mere data point avoids the social dimensions of health and thus fails to improve population health for all. Failing to include populations who are Black, Indigenous, and people of color (BIPOC) in health research means researchers actually know very little about the effect of environmental contaminants on a range of population health outcomes. This commentary offers different practical solutions, such as naming racism in research, including BIPOC in leadership positions, mandating requirements for discussing "race", conducting far more holistic analyses, increasing community participation in research, and improving racism training, to address the myriad of ways in which structural racism permeates environmental epidemiology questions, methods, results and impacts.

A linear systems approach to protect the night sky: implications for current and future regulations

The persistent increase of artificial light emissions is causing a progressive brightening of the night sky in most regions of the world. This process is a threat for the long-term sustainability of the scientific and educational activity of ground-based astronomical observatories operating in the optical range. Huge investments in building, scientific and technical workforce, equipment and maintenance can be at risk if the increasing light pollution levels hinder the capability of carrying out the top-level scientific observations for which these key scientific infrastructures were built. Light pollution has other negative consequences, as e.g. biodiversity endangering and the loss of the starry sky for recreational, touristic and preservation of cultural heritage. The traditional light pollution mitigation approach is based on imposing conditions on the photometry of individual sources, but the aggregated effects of all sources in the territory surrounding the observatories are seldom addressed in the regulations. We propose that this approach shall be complemented with a top-down, ambient artificial skyglow immission limits strategy, whereby clear limits are established to the admissible deterioration of the night sky above the observatories. We describe the general form of the indicators that can be employed to this end, and develop linear models relating their values to the artificial emissions across the territory. This approach can be easily applied to other protection needs, like e.g. to protect nocturnal ecosystems, and it is expected to be useful for making informed decisions on public lighting, in the context of wider spatial planning projects.