Spatial and Spatio-temporal Epidemiology

This study shows that the quality of the morbidity data is sufficient to allow for meaningful analyses of spatiotemporal dynamics and provides a significant contribution to understanding the 1918-1920 influenza pandemic in Switzerland by complementing existing mortality- focused research with a morbidity perspective. Previous studies have examined the spatial patterns of mortality during the 1918-1920 influenza pandemic and associated explanatory factors. However, while mortality reflects the severity of a pandemic, a full understanding requires analysis of both morbidity and mortality. For the first time, this study systematically analysed district-level morbidity data for all of Switzerland and their associations with several ecological determinants. The spatial pattern of morbidity with the spatial pattern of mortality were also compared to investigate potential differences. Spatial clustering was assessed using the Getis-Ord Gi* statistic, and geographically weighted regression was employed to evaluate local relationships between incidence and ecological variables. Across all waves, higher incidence rates were positively associated with population density, GDP per capita, the share of industry, and the number of private physicians per km{superscript 2}. Conversely, GDP per capita and industrial activity were associated with lower mortality, while a higher proportion of men in a district correlated with lower incidence and higher mortality. The share of individuals aged 20- 39 years was associated with both higher incidence and higher mortality. These findings highlight that those factors shaping morbidity patterns can differ from those influencing mortality, emphasizing the importance of examining both dimensions for a comprehensive understanding of pandemic dynamics.

IntroductionAtmospheric conditions under climate change increase pressure on healthcare systems. Especially, the intensive care units (ICU) are vulnerable due to low buffer capacity and high utilization rates. MethodsDaily ICU cases from 2009 to 2023 were derived from the German statutory health insurance data of eleven regional AOK insurances. Cases were stratified by age and sex. Generalized additive models were used to investigate the associations between daily ICU cases and lagged atmospheric variables. Thirteen intensive care relevant diseases were analyzed using disease-specific predictor sets. Analyses were conducted for regions derived from a human-biometeorological characterization of Germany. Model performance was assessed using (weighted) explained deviance. ResultsOver the 15-year study period, 9,970,548 ICU patients were recorded (44% women), 74.3% aged [≥]60 years. Trauma was the most common ICU-related disease, followed by non-ST elevation myocardial infarction (NSTEMI), pneumonia and ischemic stroke. ICU demand was most sensitive (p [≤] 0.05) to pressure-related factors, thermo-physiological parameters and ozone concentration. In terms of sex-age differences, atmospheric factors affected men more frequently, while women were more impacted by cold weather and particulate matter (PM10). Heat was more relevant for patients aged [≥]60 years. The NSTEMI model in Central Eastern Germany performed best (weighted explained deviance of 49.3%). In males [≥]60 years, heatwaves were associated with a reduced risk of ICU cases (Relative Risk = 0.94, 95%-Confidence Interval 0.89 to 0.99). ConclusionThe study identified key atmospheric factors for ICU, enabling the German healthcare system to prepare better for short-term impacts of meteorological and air quality factors. KEY MESSAGESWhat is already known on this topic: O_LIThe atmospheric changes have a direct impact on public health and the inpatient care, particularly in intensive care units. C_LIO_LIConsequently, there is a necessity to investigate the influence of atmospheric factors on intensive care in order to prepare the healthcare system for the new circumstances. C_LI What this study adds: O_LIThe study provides evidence that atmospheric factors influence the intensive care in Germany and describes age and sex-specific aspects. C_LIO_LIThe results offer valuable insights into how different atmospheric factors affect the demand for intensive care in hospitals. C_LI How this study might affect research, practice or policy: O_LIThe study enables the German healthcare system to better prepare for short-term effects of atmospheric factors, and structural or resource-related adjustments could be made in hospitals to anticipate for short-term fluctuations in intensive care demand. C_LI

Suicide is one of the worlds leading public health problems, with more than 720,000 deaths annually. Suicide has traditionally been studied from an individual perspective. However, research has increasingly highlighted the influence of community-level factors on suicide risk. This study aimed to (1) analyse the spatial distribution of suicide mortality at the provincial level in Spain (2018-2022); (2) perform stratified analyses by sex and age group; and (3) compare suicide risk across different phases of the COVID-19 pandemic. We used data from the Spanish National Institute of Statistics on 19,381 suicide deaths in 47 peninsular provinces between 2018 and 2022. Covariates included sociodemographic (e.g. aging rate, population density), economic (e.g. unemployment, GDP), and environmental (e.g. temperature) indicators. Bayesian hierarchical spatial Poisson regression models were fitted to estimate suicide risk and identify significant contextual variables. The general spatial model revealed a higher risk of suicide in provinces with lower population density, higher aging rates, and lower health expenditure. Other covariates such as gross domestic product, unemployment, or temperature were associated with specific sex or age groups. Suicide risk was highest in the northwestern provinces and lowest in the central regions. Stratified analyses showed similar patterns across gender and age groups, and between time periods, with some variations in spatial distribution. This study reveals significant spatial heterogeneity in suicide risk across Spanish regions, influenced by socio-demographic, economic, and environmental factors. These findings underline the importance of regionally tailored suicide prevention policies, especially in aging and low-density areas with low health investment. Key MessagesWe examined spatial patterns and socioeconomic and environmental determinants of suicide mortality in 50 Spanish provinces between 2018 and 2022. We found persistent geographical inequalities in suicide rates, with higher mortality in low-density provinces and those with older populations, and protective effects associated with health expenditure. These findings highlight the importance of place-based suicide prevention strategies that consider regional disparities and socioeconomic vulnerabilities.

IntroductionObesity and related health conditions are unevenly distributed across neighborhoods, often co-occuring with multiple health challenges and socioeconomic disadvantages. Using an ecosyndemic framework, which integrates ecological and social dimensions that contribute to the clustering of health problems, this study examines how adverse obesity-related health outcomes spatially cluster in relation to obesogenic environments and socioeconomic position (SEP) across Dutch neighborhoods. MethodsNationwide neighborhood-level data on health outcomes, obesogenic environmental exposures (food environment, walkability, drivability, bikeability, sports facilities), and SEP were combined for all inhabited Dutch administrative neighborhoods in 2016 (N=12,420). Cluster analysis was used to identify distinct neighborhood profiles and descriptive statistics to characterize each cluster, with spatial patterns visualized using an interactive heatmap and principal component plots. ResultsFive neighborhood clusters were identified. The Ecosyndemic cluster (N=1,070 neighborhoods) exhibited the highest burden of obesity (17% [IQR 16;19), chronic diseases (36% [IQR 33;38%) and risk of anxiety/depression (55% [IQR 51;58]), unhealthy food environments and low SEP. In contrast, the Privileged cluster (N=6,425) had more favorable health outcomes and living conditions, including lower obesity prevalence (12% [IQR 11;14]). The Psychosocial Vulnerability cluster (N=991) was notable for elevated risk of anxiety/depression (47% [IQR 43;51]) combined with relatively low obesity (11% [IQR 8;12]). The Syndemic cluster (N=1,836; obesity 15% [IQR 14;17]) and Towards Privileged cluster (N=2,098; obesity 12% [IQR 10;13]) represented intermediate profiles. ConclusionObesity and related health issues frequently cluster with unfavorable environment and SEP at the neighborhood level. The ecosyndemic framework offers a novel approach for identifying high-risk areas and supports targeted, social and place-based interventions.

AbstractO_ST_ABSImportanceC_ST_ABSGeneral responders of the World Trade Center (WTC) Health Program (WTCHP), who were uniquely exposed to chemical toxicants and extreme psychological stress during the 2001 terrorist attack, now experience a wide range of unusually prevalent health outcomes for a mid-aged population, including frailty, Post Traumatic Stress Disorder (PTSD), and depression. ObjectiveWe investigated whether these outcomes are associated with urban environmental exposures experienced in the two decades post 9/11. DesignProspective cohort study. SettingWTCHP general responders cohort. ParticipantsWe included 18,861 WTCHP general responders between the years 2003 to 2023 who took part in rescue, recovery, and clean-up tasks following the 9/11/2001 attack on the WTC. ExposuresWe evaluated the distinct and combined associations with annual fine particulate matter (PM2.5), temperature, and Green View Index (GVI) and assessed interactions with WTC-exposures. OutcomesWe assessed frailty using a validated index developed specifically for the WTCHP. We determined PTSD and depression status based on repeated test scores from validated tools administered during the monitoring visits. ResultsWe included 18,861 responders, 81.89% were males, and the mean age at entry was 47. Interquartile range increases in PM2.5 and temperature were significantly associated with increased frailty, PTSD, and depression scores, while greenness (GVI) was protective. A decile increase in the overall exposure mixture was associated with a 0.50% (95% confidence interval 0.08; 0.94) increase in frailty and a 0.10 unit (0.02; 0.18) increase in PTSD scores, primarily driven by temperature. Importantly, the exposure-mixture was associated with an increased risk of reaching a clinical threshold for PTSD (odds ratio: 1.013[1.001,1.024]). Finally, the associations between the exposure-mixture and mental health were significantly amplified among responders with high WTC-exposures, though no such modification was observed for frailty. Conclusion and relevanceExposures to heat and PM2.5 were associated with increased frailty, PTSD, and depression, while greenness exposure was protective. Responders who experienced more intense WTC exposures were more vulnerable to later-life environmental exposure-mixture effects on mental health. These findings may help explain the elevated burden of these conditions among WTCHP responders and suggest avenues for public health interventions including education on risk mitigation strategies.

BackgroundWhile coal mine fire smoke has been linked to short-term increases in cardiovascular events, there is little evidence on long-term risks. We investigated longer-term risk of major adverse cardiovascular events (MACE) following the 2014 Hazelwood coal mine fire in regional Victoria, Australia. MethodsIn this cohort study, combined administrative data on ambulance attendances, emergency department presentations, hospital admissions, and mortality from March 2014 to June 2022, with survey data from 2016/17. Time-location diaries for the mine-fire period were combined with modelled fire-related particulate matter [≤]2.5{micro}m in diameter (PM2.5) to estimate individual exposures. We analysed the association between PM2.5 exposure and time to MACE using a recurrent event survival analysis, adjusting for key confounders. Outcomes were examined over 8 years of follow-up and stratified by time. ResultsN = 2,725 cohort members agreed to linking their survey responses to administrative data. There was no detectable effect of fire-related PM2.5 exposure on overall risk of MACE during 8-year follow-up. However, there was weak evidence suggesting increase in MACE risk in the first 3 years post-fire, with hazard ratios ranging from 1.05-1.18 per 10{micro}g/m3 of daily average PM2.5 exposure. Nearly all analyses of cardiovascular death detected an increased risk across the entire follow-up period, with hazard ratios ranging from 1.19-1.25 per 10{micro}g/m3. ConclusionsWe found smoke exposure predicted an increase in cardiovascular health service use in the three years after the mine fire. There was additional evidence that the mine fire increased risk of cardiovascular death over the entire 8-year follow-up. This suggests that cardiovascular screening should be a routine component of planning recovery after landscape fires.

ImportancePrenatal cannabis exposure is increasing in prevalence, yet its associations with early brain development--particularly how the timing and frequency of exposure across gestation relate to neonatal brain structure--remain insufficiently understood. Clarifying these associations is essential for informing early risk identification and guiding perinatal care. ObjectiveTo examine associations between patterns of maternal prenatal cannabis exposure, including exposure presence, gestational timing, and frequency of exposure, and neonatal brain structure and microstructure during the first month of life. Design, Setting, and ParticipantsThis cohort study included 1,782 mother-infant dyads (221 with PCE) from the HEALthy Brain and Child Development Study. Mother-reported prenatal cannabis exposure was assessed using the validated Timeline Follow-back method. Infants underwent natural-sleep magnetic resonance imaging, including T2-weighted structural imaging and diffusion imaging, within the first month of life. Main Outcomes and MeasuresAssociations between prenatal cannabis exposure and regional T2-weighted volumes and diffusion white matter microstructure metrics examined (1) exposure presence, (2) gestational timing of exposure, and (3) frequency of exposure within exposed infants. ResultsAny prenatal cannabis exposure was associated with brain volume differences in cerebellar and subcortical limbic regions, including smaller amygdala, thalamic, and cerebellar vermis volumes and larger caudate, hippocampal, and cerebellar cortex volumes. Timing-specific analyses revealed divergent patterns: first trimester exposure was associated with smaller volumes in select regions, whereas exposure that continued into the third trimester was associated with larger volumes in overlapping structures, with additional subcortical volumetric differences observed. White matter microstructure alterations were observed only among infants with exposure that continued into the third trimester. Within the exposed subgroup, higher frequency of cannabis exposure was associated with larger cerebral white matter volumes and white matter microstructural differences in white matter regions. Conclusions and RelevanceIn infants with maternal prenatal cannabis exposure, we observed timing- and frequency-dependent differences in brain development within the first month of life. These findings underscore the importance of considering not only the presence of exposure, but also when and how much cannabis is used during pregnancy to support targeted prenatal counseling and early developmental monitoring for exposed infants. Key PointsO_ST_ABSQuestionC_ST_ABSIs prenatal cannabis exposure associated with brain development in the first month of life? FindingsIn a cohort[ABS] of 1,782 mother-infant dyads, prenatal cannabis exposure was associated with region-specific differences in neonatal brain volumes. Brain volume and diffusion white matter microstructure associations differed between exposure limited to the first trimester versus exposure that continued into the third trimester. Greater frequency of exposure across gestation was also associated with volumetric and microstructural differences. MeaningThe timing and frequency of prenatal cannabis exposure is associated with alterations in neonatal brain development, underscoring the importance of addressing cannabis use in pregnancy.

BackgroundMuch of the worlds historical and current epidemiological data remains locked in static formats, such as PDF situation reports or image-based surveillance bulletins. Recovering this data for spatial analysis typically requires proprietary software (e.g., ArcGIS) or laborious manual entry, which is prone to transcription errors. MethodsI developed Map Liberator, an open-source application built in R and Shiny. It provides a split-screen digitisation interface that allows users to overlay static reference maps alongside interactive administrative boundaries. The tool uses a stateful rendering engine to manage complex geometries (up to Admin Level 3) and facilitates the extraction of binary, numeric, or qualitative data directly into a structured, machine-readable format. ResultsI demonstrate the tools utility by digitizing Lassa Fever surveillance data from Nigeria (2018-2025). The tool successfully aligned static situation reports with official Local Government Area (LGA) boundaries, allowing for the rapid recovery of binary presence/absence data that was previously inaccessible for computational modelling. ConclusionsMap Liberator provides a low-barrier, cost-effective solution for field epidemiologists and researchers to liberate spatial data from static reports, supporting the principles of FAIR (Findable, Accessible, Interoperable, Reusable) data in global health.

Lead exposure is a major environmental health concern, especially in childhood, due to its neurotoxic effects even at low levels. This cross-sectional observational study aims to evaluate the association between lead accumulation in tooth enamel, cognitive performance, and dietary patterns in children aged 7 to 9 years belonging to the Archdiocesan Educational Network of Guayaquil, Ecuador. A total of 384 participants will be selected using stratified sampling according to socioeconomic status. Lead levels will be assessed using a validated dental enamel biopsy technique, while IQ will be measured using the Wechsler Intelligence Scale for Children - Fifth Edition (WISC-V). Dietary intake will be assessed using a Food Frequency Questionnaire (FFQ) validated for the Ecuadorian population. All procedures will ensure the safety, comfort, and confidentiality of participants. Potential risks, such as emotional distress or academic disruption, will be minimized through adapted protocols and ethical safeguards. This study seeks to provide critical local evidence on environmental lead exposure and its association with cognitive outcomes and dietary, to help inform future public health efforts.

BackgroundPediatric poisonings are a significant cause of emergency admissions, often linked to accessible household toxins. This study investigates the epidemiological patterns, clinical presentations, and management strategies at a tertiary care hospital in Algiers, Algeria. MethodsA retrospective descriptive analysis was conducted on anonymized pediatric poisonings cases. Variables included age, sex, type of ingestion, intent (accidental vs. voluntary), substances involved, endoscopic findings, hospitalization duration, and management approach. Results59 pediatric poisoning cases were analyzed, which were predominantly accidental and affected children aged 0-6 years. Medication (n=24) and caustic ingestions (n=25) were the most frequent agents. Caustic cases, which primarily affected older toddlers, led to moderate mucosal injury in three patients. Carbon monoxide (n=8) affected a wide age range, including infants and adolescents. Management was mainly supportive; while most medication cases were discharged in two days, caustic cases required hospitalization for up to 14 days. These findings highlight the need for targeted public health interventions. ConclusionPediatric poisonings in this setting are largely preventable. Unsafe storage of medications and caustic agents is the primary contributor. Public health interventions focusing on household safety, caregiver education, and standardized clinical protocols are essential. Key PointsO_ST_ABSWhat is knownC_ST_ABSO_LIPediatric poisonings are common emergency admissions. C_LIO_LIToddlers are the most vulnerable age group. C_LIO_LIUnsafe household storage is a major risk factor. C_LI What is addedO_LIFirst detailed Algerian hospital-based analysis of pediatric intoxications. C_LIO_LICharacterizes the dual burden of caustic and medication poisonings in a North African pediatric setting, with caustic ingestions accounting for the most prolonged hospitalizations and requiring endoscopic evaluation. C_LIO_LIDemonstrates that carbon monoxide poisoning affects a broad age range including infants, highlighting environmental domestic exposure as a distinct and underappreciated risk in this context. C_LI

BackgroundAir pollution is a potentially modifiable risk factor for dementia with a population attributable risk fraction of 3%. Little is known about the causal mechanisms behind the association, so we aimed to investigate this. MethodsData from the UK Biobank were used to investigate the association between six measures of air pollution (NO2, NOx, PM2{middle dot}5-10, PM2{middle dot}5, PM2{middle dot}5 absorbance and PM10) and dementia incidence. Indirect pathways through four mediators (cardiovascular conditions, mental health treatment, insufficient exercise and social isolation) were explored. Logistic regression was used to model the associations between air pollution, mediators and dementia. Casual mediation analysis implemented using the g-formula was used to investigate the joint indirect effect through the mediators. FindingsExposure to the highest quintile of PM2{middle dot}5 (Rte:1{middle dot}14, 95% CI:1{middle dot}06-1{middle dot}23), NOx (Rte:1{middle dot}11, 95% CI:1{middle dot}03-1{middle dot}20) or NO2 (Rte:1{middle dot}08, 95% CI:0{middle dot}99-1{middle dot}16), compared to the lowest quintile, was associated with higher dementia risk. Most of the observed association resulted from the direct effect of air pollution, consisting of pathways not captured through considered mediators. Amongst those in the highest PM2{middle dot}5 quintile, jointly intervening on the four mediators would result in a 1% reduction in risk of dementia (Rpnie:1{middle dot}01, 95% CI: 1{middle dot}01-1{middle dot}02). The randomised pure natural indirect effect was similar for NO2 (Rpnie:1{middle dot}01, 95% CI: 1{middle dot}00-1{middle dot}01) and NOx (Rpnie:1{middle dot}01, 95% CI: 1{middle dot}01-1{middle dot}02). InterpretationMost of the association between dementia and PM2{middle dot}5, NO2 and NOx occurs through the direct effect of air pollution, or other unmeasured mediators, and not pathways through these four mediators. FundingMedical Research Council (Grant MR/W006774/1).

BackgroundParkinsons Disease (PD) is a progressive neurodegenerative disorder influenced by both genetic and environmental factors. Prolonged exposure to pesticides has been proposed as an environmental risk factor, yet its relationship with structural brain differences in human adults remains unexplored. ObjectiveTo investigate the association between occupational pesticide exposure and volumetric differences in specific brain regions, and to evaluate the relationship between pesticide exposure and PD diagnosis using data from UK BioBank. MethodsStructural MRI (T1-weighted scans) were used to extract regional brain volumes. The study population contained 21,049 UK BioBank participants, of which 912 participants indicated they had occupational pesticide exposure. General linear models were utilized to assess the association between pesticide exposure and regional brain volume differences, adjusting for participant demographics, socioeconomic status, study site where imaging was conducted, and genetic principal components as covariates. A Cox proportional hazards model was utilized to assess the association between pesticide exposure and PD diagnosis (ICD-10 code G20). ResultsSignificant negative associations were observed between occupational pesticide exposure and volumes of total gray matter, cortex, thalamus, ventral diencephalon, cerebellum cortex, cerebellum white matter, and brainstem. Significant positive associations were observed between occupational pesticide exposure and white matter hyperintensities and inferior lateral ventricle volumes. No significant hemispheric lateralization was observed, and adjusting for fluid intelligence scores did not significantly change model estimate values, demonstrating brain volumetric and pesticide associations were not confounded by differences in fluid intelligence. A trending, non-significant association between pesticide exposure and PD diagnosis was observed (Odds Ratio (95% CI) 1.36 (0.98 to 1.90) p=<0.12). ConclusionOccupational pesticide exposure is associated with structural reductions in volume within several brain regions, and increases in white matter hyperintensities and ventricular volume, supporting a possible neurodegenerative effect. This is the first large scale study to link adult pesticide exposure to region-specific brain volume differences utilizing non-invasive structural neuroimaging. These findings highlight a putative link between pesticide exposure and gross neuroanatomical changes in adulthood which may impact overall brain health.

The global incidence of dengue has been rising during the past several decades as a result of increased risk as well as enhanced surveillance. This positively-sloped long-term trend in dengue cases has made it difficult to identify anomalously high intensity years. To address this issue, constructed a hierarchical Bayesian Poisson regression model to extract the long-term trend of annual incidence across 57 countries from 1990-2023 and quantify the difference between reported cases and baseline, which we call the Relative Intensity Score (RISc). To accommodate the peak transmission that often extends through December and January in the Southern Hemisphere, we used an annual time frame from July to June to determine RISc in this region (e.g., for these counties, the 2023-24 transmission season is listed as 2023). RISc provides a standardized measure of incidence intensity that adjusts for location- and time-specific contexts, thereby allowing intensities to be compared across geographies and timeframes. We found that globally, 1995, 1998, 2019, and 2023 represented the highest RISc years and that high RISc tends to follow multi-year cycles. Finally, we identified that temperature anomalies are most strongly associated with elevated RISc. This study provides the first standardized global analysis of dengue intensity, and provides a window into how spatial and temporal trends of dengue intensity may continue to evolve into the future.

BackgroundThe dynamics of HIV and ZIKV coinfection among pregnant women remain understudied, and its impacts on neonatal health still need to be defined. This gap is particularly concerning given the significant public health risks it can cause, especially in Latin America and the Caribbean, where the Zika virus is still circulating. MethodsWe conducted a transversal ecological study using aggregated data from 2015 to 2023. To do so, we developed a compartmental model that included a Susceptible-Infected-Recovered (SIR) compartment for pregnant women related to HIV and ZIKV infection status, as well as SI compartments for their newborns and ZIKV-carrying mosquitoes to perform simulations representing different epidemiological scenarios. We calculated the HIV/ZIKV basic reproduction number R0. Sensitivity analysis was performed to identify the model parameter with the greatest impact on this metric. Finally, we applied personal and sexual protection, medical treatment for Zika, and antiretroviral therapy as control measures against viral infections to evaluate the most effective strategy to improve neonatal health outcomes. ResultsThe basic reproduction number [R]0 associated with HIV/ZIKV coinfection among pregnant women varied in the range [0.09, 1.29] in the countries studied. The sensitivity analysis revealed that the [R]0 was most sensitive to the mosquito biting rate and the pregnant womens death rate. ZIKV infection rate among pregnant women had a greater impact on the number of newborns with related health problems compared to HIV infection rate. The introduction of ZIKV among pregnant women was enough to cause a surge in the number of newborns with related health issues, demonstrating a greater impact than HIV on neonatal health. When control strategies were applied to the model, simulations demonstrated that their application needed to be maintained concurrently over time and that medical treatment of Zika was the measure having the least influence on the coinfection. ConclusionSince pregnant women infected with HIV are particularly vulnerable to other infections such as ZIKV, it is crucial to improve antenatal care among them. Continued monitoring and increased prevention of HIV sexual transmission is also necessary to ensure maternal and child health. In order to optimize public health interventions, it is important to extend the research to strengthen our understanding of the implications of HIV-ZIKV coinfection among pregnant women and its effects on their children.

BackgroundCannabis use is highly prevalent among people who use unregulated drugs. While daily cannabis use has been hypothesized to provide protective effects through substitution or tolerance mechanisms, the relationship between cannabis use frequency and overdose risk remains poorly understood, particularly for infrequent users. MethodsWe conducted a secondary analysis of cross-sectional interview data from people who use unregulated drugs in Vancouver, British Columbia, collected during the fentanyl crisis (November 2019-July 2021; n=657). Binary logistic regression examined associations between self-reported cannabis use frequency (five categories: less than monthly, 1-3 times per month, weekly, more than weekly and daily) and non-fatal overdose in the preceding six months. Daily use served as the reference category. Models adjusted for age, gender, ethnicity, homelessness, mental health, HIV status, incarceration and daily use of alcohol, opioids, fentanyl, cocaine and stimulants. ResultsAmong 657 participants, 95 (14.5%) reported non-fatal overdose in the past six months. In adjusted models with daily cannabis use as the reference, infrequent cannabis use was associated with significantly increased odds of overdose: use 1-3 times per month (aOR=3.17, 95% CI: 1.50-6.69, p=.002) and more than weekly use (aOR=3.13, 95% CI: 1.70-5.76, p<.001) showed approximately three-fold increased odds compared to daily use. Less frequent use showed non-significant trends in the same direction (less than monthly: aOR=1.73, 95% CI: 0.89-3.37, p=.109; weekly: aOR=1.44, 95% CI: 0.59-3.51, p=.421). Sensitivity analysis restricted to participants with daily stimulant or fentanyl use (n=148) revealed even stronger associations. ConclusionsInfrequent cannabis use was associated with substantially increased overdose risk compared to daily use. This frequency-dependent relationship, with infrequent users at highest risk, likely reflects tolerance differences: infrequent users lack tolerance to synergistic cannabis-opioid effects. These findings were completely obscured in preliminary analyses that dichotomized cannabis use as daily versus less-than-daily, demonstrating how analytical choices can mask critical public health insights. Current harm reduction approaches, including cannabis distribution programs, should incorporate frequency-dependent risk communication and develop strategies to protect infrequent users who may be at heightened overdose risk.

BackgroundDengue virus infection remains among the most prevalent infectious diseases globally, with an estimate of 100-400 million cases occurring each year. Prior ecological studies have documented spatial and temporal correlations between dengue occurrence and either socioeconomic or climatic conditions independently. The aim of this study was to analyze the association between multidimensional typologies, including socioeconomic, geographic, climatic, and infrastructure factors and the rate of dengue cases in Colombia. MethodsAn analytical, observational, ecological study with repeated measures that included six years of aggregated quantitative data study from 2015 to 2020, based on national registry data from several sources. A spatial Generalized Additive Mixed Model (GAMM) was used to identify the probable factors associated with the frequency of dengue in Colombia. Socioeconomic, infrastructure, geographic, and climatic factors included Multidimensional Poverty Index (MPI), altitude, population density, road density, education and public services coverage, altitude, temperature, precipitation, relative humidity, and presence of El Nino-Southern Oscillation (ENSO) in the period of analysis. ResultsDuring the study period, 448,774 cases of dengue fever were reported in Colombia, with overall monthly median of 6280 cases (IQR: 2842-9278). The highest number of cases was reported in 2019 with 118,956 cases. Higher levels of drinkable water service coverage, education access coverage, and relative humidity were negatively associated with dengue frequency, showing lower case frequency. While higher GDP per capita and greater participation in the subsidized health system were associated with higher incidence of dengue, although the latter showed substantial variability in extreme values. Precipitation and maximum and minimum temperatures showed unimodal associations, with risk concentrated at intermediate values, while altitude and population density revealed complex multimodal patterns. Municipal performance, a composite index that assesses the efficiency and management capacity of local governments, showed a negative association with dengue occurrence, indicating lower risk in better-performing municipalities. ConclusionsA complex interaction was found between socioeconomic, geographic, climatic, and infrastructure factors. These findings may highlight the need for multidimensional approaches in dengue prevention and control policies, that consider the specific conditions of each community. Research is required to better understand the factors that affect the dynamics of dengue. Factors identified at this local level may be useful in different geographical regions, especially in the context of climate change related vulnerabilities. Author summaryDengue fever affects millions worldwide, with Colombia reporting over 150,000 cases in 2023. Understanding what drives dengue transmission is crucial for prevention, but most studies focus on either climate or social factors alone. We studied how multiple factors such as poverty, access to services, climate conditions, and government capacity relate to dengue patterns across Colombian municipalities from 2015-2020. We found that dengue occurrence is associated with a complex mix of factors. Warmer temperatures and moderate rainfall were associated with more cases, but so were factors like limited access to clean water and education. Surprisingly, areas with higher economic development also reported more cases, possibly explained by better disease detection and diagnosis due to better healthcare access. Well-performing local governments were associated with lower disease frequency. These findings suggest that fighting dengue requires comprehensive approaches that go beyond mosquito control. Communities need improved water access, better education, and strong local governance. As climate change progresses, understanding these multiple vulnerabilities becomes even more important to protect vulnerable populations, particularly in tropical regions where dengue is endemic.

Severe neonatal hyperbilirubinemia remains a leading cause of preventable neonatal morbidity and mortality in low- and middle-income countries (LMICs), where unreliable electricity supply, limited specialist availability, and high treatment costs constrain access to effective phototherapy. There is limited evidence on scalable, climate-resilient phototherapy solutions suitable for decentralised care delivery. We conducted a multicentre implementation study evaluating a fully solar-powered total-body phototherapy system deployed across tertiary and grassroots healthcare facilities in Nigeria between February 2024 and January 2026. The study followed a phased design: (1) specialist-controlled observational deployment at a tertiary hospital, (2) corroborative deployment at additional tertiary centres across climatic regions, and (3) task-shifted grassroots implementation in mission-owned hospitals. Neonates with moderate-to-severe hyperbilirubinemia were treated according to standard clinical protocols. Primary outcomes were successful reduction of bilirubin to [&le;]11.5 mg/dL, treatment duration, safety, and operational feasibility under electricity-independent conditions. Across all phases, nearly 2000 neonates have been screened and more than 650 neonates received treatment with the solar-powered phototherapy system. All treated neonates achieved bilirubin reduction to the predefined safety threshold, with a mean treatment duration of 19.2 {+/-} 13 hours during the initial observational phase. No treatment interruptions due to power failure occurred, and no phototherapy-related adverse events, neurological complications, or treatment-related mortality were observed. Treatment was safely delivered by junior clinicians and health assistants under task-shifted models in grassroots settings. The intervention eliminated the need for exchange blood transfusion among treated neonates and substantially reduced hospitalisation duration compared with conventional care pathways. This study demonstrates that fully solar-powered phototherapy can be safely, effectively, and sustainably implemented across multiple levels of the health system in a low-resource setting. By removing dependence on grid electricity and specialist personnel, the intervention addresses key structural barriers to neonatal care while supporting task shifting and climate-resilient service delivery. The findings support policy consideration of decentralised, infrastructure-independent phototherapy as a strategy to reduce neonatal morbidity and mortality in LMICs.

BackgroundDengue fever is a major neglected tropical disease with a rapidly rising global burden, and localized outbreaks are increasingly reported in southern subtropical China. Fujian Province, a coastal subtropical region with favorable ecological conditions for Aedes albopictus breeding and frequent cross-border exchanges with dengue-endemic areas, has had continuous local dengue cases for over a decade, raising concerns about the establishment of a stable natural endemic focus. Sustained local dengue transmission is defined by four core criteria, but no systematic assessment of these criteria has been conducted for Fujian using long-term multi-dimensional surveillance data. We aimed to evaluate whether a natural endemic focus for sustained local dengue transmission has been established in Fujian Province from 2014 to 2024 using four core evidence dimensions. MethodsWe extracted data on imported and locally acquired dengue cases in Fujian from 2014 to 2024 from Chinas National Notifiable Disease Reporting System (NNDRS). Serological surveillance for dengue IgG antibodies and virological surveillance for dengue virus in Aedes albopictus were conducted at seven sentinel sites. The study period was stratified into three phases based on the impact of COVID-19 non-pharmacological interventions: pre-pandemic (2014-2019), pandemic(2020-2022), and post-pandemic(2023-2024). Descriptive epidemiological analysis and data visualization were performed using R software (version 4.4.1), with t-tests for continuous variables and {chi}{superscript 2} tests for categorical variables. ResultsA total of 3,606 dengue cases were reported in Fujian during the study period, including 1,229 imported and 2,377 locally acquired cases. Key findings were as follows: (1) Temporal distribution: Local dengue transmission was completely interrupted during the 2020-2022 COVID-19 pandemic (0 local cases, only 26 imported cases), and resumed at a low level in 2023-2024 (160 local cases). (2) Serology: The overall population dengue IgG antibody positivity rate was 4.2% (66/15,736), with no statistically significant difference between pre-epidemic (3.8%, 30/7,835) and post-epidemic seasons (4.5%, 36/7,901; P=0.48), and no year with a positivity rate exceeding 10%. (3) Vector surveillance: Only one dengue virus-positive sample was detected among 385,000 Aedes albopictus mosquitoes collected during routine surveillance (Taijiang District, Fuzhou, October 2017), with no viral nucleic acid detected in all other samples. (4) Age distribution: The mean age of locally acquired cases (46.1{+/-}19.8 years) was significantly higher than that of imported cases (35.8{+/-}11.2 years, P<0.001), and local cases were concentrated in the middle-aged group (40-60 years) with no child-dominant pattern observed. ConclusionsFujian Province has not established a stable natural endemic focus for sustained local dengue transmission, and imported cases are the primary driver of local outbreaks in the region. Strengthened surveillance and early management of imported cases, integrated vector control targeting Aedes albopictus, and targeted public health education are critical and essential strategies to prevent the establishment of a dengue natural endemic focus in Fujian and other subtropical coastal regions with similar epidemiological characteristics. Author SummaryDengue fever is a rapidly spreading neglected tropical disease worldwide, and southern China faces persistent threats of local transmission due to favorable ecological conditions for mosquito breeding and frequent cross-border travel. Fujian Province, a subtropical coastal region in southeastern China, has reported annual local dengue cases for over a decade, raising public health concerns about the potential establishment of a stable natural endemic focus--where the virus circulates sustainably without relying on imported cases. To address this critical question, we conducted a comprehensive 11-year assessment (2014-2024) of dengue transmission in Fujian using four key evidence dimensions defined for identifying dengue endemic foci: the continuity of local cases independent of imported sources, population antibody levels, dengue virus detection in local mosquitoes (Aedes albopictus), and the age distribution of infected patients. We also leveraged the COVID-19 pandemic(2020-2022) as a unique natural experiment, during which strict travel restrictions drastically reduced imported dengue cases, to test whether local transmission could persist on its own. Our findings showed that local dengue transmission in Fujian completely stopped during the COVID-19 pandemic and only resumed when cross-border travel and imported cases recovered, confirming local transmission is entirely dependent on imported virus sources. Additionally, the local population had a very low dengue antibody positivity rate (4.2%), dengue virus was detected in only one mosquito sample over 11 years of surveillance, and local cases were concentrated in middle-aged adults (not children--the typical group affected in endemic areas). Together, these results confirm that Fujian Province has not established a stable natural endemic focus for dengue fever. While no endemic focus exists yet, Fujian remains at high risk of imported-driven local outbreaks due to its climate and cross-border exchanges. Our study highlights three critical strategies to prevent the future establishment of a dengue endemic focus in Fujian and other similar subtropical coastal regions: strengthening surveillance and early response for imported dengue cases, implementing targeted mosquito control measures during peak transmission seasons, and conducting public health education to raise awareness of dengue prevention. These evidence-based interventions are key to blocking the formation of sustained local dengue transmission and protecting regional population health.

IntroductionThe circadian clock is an internal, [~]24-hour biological timer that synchronizes physiology with the day-night cycle. Social jetlag (SJL) describes the misalignment between this internal clock and social schedules, a condition affecting approximately 70% of the population and linked to a spectrum of metabolic, mental, and cognitive health issues. This study examined how the 2022 FIFA World Cup disrupted normal childrens sleep routines and other associated factors from parents prospect. MethodsAn online, cross-sectional survey was distributed to parents (N=848). The questionnaire collected sociodemographic data, childrens habitual sleep habits, and changes perceived during the 2022 FIFA World Cup. SJL was defined as a [&ge;]1-hour delay in bedtime on weekends versus weekdays. Multivariable logistic regression analyses identified factors associated with perceived sleep changes and SJL. ResultsOver half (53.4%) of the children exhibited pre-existing weekend SJL. Children aged 5-11 (OR=1.847, p<0.001), higher socioeconomic status (OR=1.383, p<0.001), international residency (OR=2.845, p<0.001) were significant predictors of baseline weekend SJL. During the tournament, 33% and 17.8% of parents reported their children had delayed sleep ([&ge;]1 hour) on weekdays and weekends due to match watching, respectively. Regression analysis revealed that these parental perceived FIFA impact on their children sleep was significantly associated with weekdays SJL OR= 1.958, p=0.001 and weekends OR= 1.784, p=0.009 during the FIFIA season. DiscussionOur findings indicate that major social events can exacerbate circadian misalignment and SJL, likely driven by social conformation. The high prevalence of baseline SL confirms it is a widespread pediatric health issue. The vulnerability of the 5-11 age group shows SJL is not exclusively an adolescent problem. ConclusionMajor sporting events significantly disrupt childrens sleep schedules, compounding the public health issue of chronic SJL. Proactive guidance for families is needed during such events. More importantly, these findings underscore the urgent need for structural changes to align social schedules with pediatric circadian biology.

ABSTRACT/SUMMARYO_ST_ABSObjectiveC_ST_ABSCannabis use during pregnancy is increasing; associations with neonatal growth may be confounded by nicotine. We evaluated prenatal cannabis exposure (PreCE) and neonatal outcomes in a prospective cohort with biochemical control for nicotine exposure. MethodsIn the Cannabis Use During Early Life and Development (CUDDEL) study, pregnant women with a lifetime history of cannabis use were classified as PreCE if they self-reported use or had urine THC-COOH positivity at any trimester (n=297) and as unexposed if they reported no use and tested negative (n=151). Linear regression and modified Poisson models estimated associations with birthweight and small for gestational age (SGA; <10th and <5th percentiles), adjusting for sociodemographic factors, gestational age, maternal age and BMI, and urinary cotinine. Analyses stratified by cannabis use frequency (>weekly vs <monthly) and cotinine status. ResultsParticipants (N=448; 18-41 years; 85.3% non-Hispanic Black) had lower birthweight with PreCE in adjusted models (Beta=-0.08; padj=0.041). High-frequency PreCE was associated with lower birthweight compared with unexposed pregnancies (Beta=-0.13; padj=0.03), whereas low-frequency PreCE was not. Cotinine-positive PreCE showed the greatest birthweight reduction versus unexposed (Beta=-0.20; padj<0.001). PreCE was also associated with higher likelihood of SGA <5th percentile; risk was highest in PreCE+Nicotine compared with both unexposed and PreCE-Nicotine groups. ConclusionsPrenatal cannabis exposure was associated with reduced birthweight and SGA in this cohort. Nicotine co-exposure intensified these associations, yet effects persisted without cotinine, supporting cannabis as an independent perinatal risk factor and emphasizing the value of cotinine assessment in populations where blunt use or secondhand exposure is common.