BackgroundFirefighters have frequent exposure to carcinogens and an increased risk of cancer. Wildland-urban interface (WUI) fires, which involve both structures and undeveloped wildland fuels, pose unique challenges to the health of firefighters. However, the extent of health risks associated with these fires remains underexplored.ObjectivesThis study aims to identify altered urine metabolites and metabolic processes among male firefighters that were associated with WUI fires as compared with municipal structure fires (MSF).MethodsUntargeted metabolomic profiling was applied to pre-exposure (baseline) and postfire urine samples collected from firefighters responding to WUI and MSF fires. Differential analysis was conducted by fitting linear mixed effects regression models on preprocessed ion intensity and exposure status while adjusting for demographic covariates. Differential metabolites by post-exposure status were identified using a false discovery rate (FDR) threshold of < 0.05. Pathway analysis was performed to identify pathways that were significantly perturbed at a Bonferroni adjusted p-value < 0.05 level. We conducted differential and pathway analyses in both the WUI and MSF cohorts and compared the two fire types in terms of the number of differentially expressed metabolites and patterns of metabolic pathway enrichment.ResultsEighty-five firefighters contributed paired baseline and post-fire samples from WUI events, and 98 firefighters contributed paired baseline and post-fire samples from MSF events. We performed metabolic profiling on baseline and postfire urine samples from WUI and MSF using four modes: HILIC(-), HILIC(+), C18(-), and C18(+) and identified metabolites against an in-house library. We identified 244, 297, 320, and 266 level-1 metabolites from the four respective modes. In the statistical analysis, the main model identified a total of 176 differential metabolites from WUI fires. For MSF, the model identified a total of 652 differential metabolites from the four respective modes. Most metabolites with significant changes after a WUI fire also changed significantly after an MSF event. Two metabolic pathways were significantly enriched after WUI fires, while 7 pathways were significantly enriched after MSF exposure and 2 pathways overlapped between the two types of fires.ConclusionFire exposure induces numerous metabolic perturbations in firefighters responding to WUI fires, potentially contributing to their elevated cancer risk. Although individual metabolites changed in a similar fashion across both WUI and MSF, MSF were associated with an increased number of metabolite changes and some of the enriched pathways differed between exposures to WUI fires vs. MSF. These findings suggest that WUI and MSF exposures may share common biological responses while also posing unique health risks to firefighters.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12940-025-01239-7.

BackgroundThe prevalence of autism spectrum disorder has risen in recent decades. Given the growing evidence that prenatal fluoride exposure may be neurotoxic, we examined associations between prenatal fluoride exposure and parent-reported autistic behaviors in preschool-aged children.MethodsWe studied 453 mother-child pairs using data from the Maternal-Infant Research on Environmental Chemicals (MIREC) study, a prospective Canadian birth cohort. Autistic behaviors were assessed in children at 3 to 4 years using the Social Responsiveness Scale-Second Edition (SRS-2) Preschool Form, where a higher score indicates more autistic behaviors. We estimated prenatal fluoride exposure using three methods: (i) maternal urinary fluoride adjusted for specific gravity (MUFSG), from spot urine samples collected at each trimester and the mean calculated across samples, (ii) daily maternal fluoride intake, based on self-reported consumption of tap water, coffee, and tea during the first and third trimesters, and (iii) water fluoride concentration in tap water. We used multivariable linear regression models to estimate associations between the SRS-2 scale T-scores and each fluoride exposure separately. We used multivariable logistic regression to estimate the association between each prenatal fluoride exposure and an elevated SRS-2 total T-score (i.e., 90th percentile or higher). Potential effect modification of MUFSG was examined by child sex, daily folic acid supplementation, and plasma total folate in pregnancy.ResultsThe mean SRS-2 total T-score for children aged 3 to 4 years was 45.3 (SD = 6.1, range = 34 to 85). The median MUFSG concentration was 0.43 mg/L (interquartile range = 0.33 mg/L). MUFSG was not significantly associated with the SRS-2 total T-score in multivariable linear regression (β = -0.16; 95% CI, -1.70, 1.39) or logistic regression (OR = 0.76; 95% CI, 0.29, 1.96). Similarly, estimated daily fluoride intake and water fluoride concentration were not associated with the SRS-2 total T-score. No effect modification was observed.ConclusionsThere was no evidence of an association between prenatal fluoride exposure and autistic behaviors in preschool-aged children, in contrast to previous MIREC research findings on lead and phthalates. Given that this cohort has relatively few children with high SRS-2 scores, further research is needed in other groups of children to more fully explore this association.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12940-025-01237-9.

Air pollution, in particular due to traffic, is suspected of increasing the risk of childhood acute leukemia (AL), most of the evidence coming from epidemiological studies and literature reviews that focused on the time around diagnosis. Using data on the national scale, we tested the hypothesis that prenatal exposure to traffic-related air pollution increases the risk of childhood AL. This case–control study included 581 cases of acute lymphoblastic leukemia (ALL) and 136 cases of acute myeloid leukemia (AML), registered in the French national registry of childhood cancer and born and diagnosed between 2010 and 2015, and 11,908 controls. Exposure indicators were evaluated at the addresses at birth and included major road length in 500 m buffers, and modeled exposures of nitrogen dioxide (NO2), fine particulate matter (PM2.5) and black carbon (BC). Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models. Exposures were considered in categories using tertiles’ cut offs or continuously for increments of ½ interquartile range. Both ALL and AML risks increased with PM2.5 exposure (OR ALL = 1.14, 95%CI = 1.08–1.20 and OR AML = 1.12, 95%CI = 1.00–1.25 for an increment of 2 µg/m3, respectively). The risk of ALL was associated with BC exposure in urban units of < 5,000 inhabitants and of 5,000–99,999 inhabitants (OR = 1.90, 95%CI = 1.22–2.97 and OR = 1.58, 95%CI = 1.16–2.17 for an increment of 0.5 10–5/m, respectively), and not in more urban municipalities. An elevated OR for AML was observed for NO2 exposure (OR = 1.4, 95%CI = 0.9–2.1 for the highest versus lowest category). There was no association with the length of major roads. The results support a role of exposure to air pollution at time of birth in the risk of childhood AL.

Exposome research seeks to understand how cumulative environmental exposures across the life course shape health outcomes. Most studies however, adopt a unidirectional, top-down model, conceptualizing individuals as passive recipients of exposure, which overlooks the social, cultural, and behavioral dynamics through which people engage with their environments and thus underestimates the human agency of those exposed in mitigating exposures. To address this gap, we introduce the concept of the anthroposome: the full range of micro-ecological practices through which individuals and communities sense, interpret, avoid, and manage environmental exposures in daily life. Drawing on anthropological theory and focusing on ethnographic methods, we outline five discovery-based approaches for integrating lived experience and social complexity into exposome science. These methods highlight how everyday practices influence exposure pathways and reveal context-specific risk management strategies conventional exposure researchers may miss. Capturing bidirectional human–environment interactions, anthroposomics repositions populations suffering from exposure as active agents who participate in shaping their exposure landscapes. Anthroposomics expands the exposome paradigm by integrating ethnographic methods into exposome research, enhancing the paradigm's relevance, effectiveness, and equity. Anthroposomics offers a foundation for preventive, community-responsive, justice-oriented environmental health interventions and policy.

Fluoride exposure and its effects on human health are controversial and highly debated. While beneficial in preventing dental caries, fluoride has been linked to skeletal and dental fluorosis at high levels, as well as other adverse health endpoints in children and adults. However, the safe range of exposure for bone health remains poorly defined. We used existing literature to quantify the dose-response relation between fluoride exposure and bone health, focusing on fracture risk and bone mineral density (BMD). We conducted a systematic review and dose-response meta-analysis by searching literature in online databases (MEDLINE/PubMed, Embase and Web of Science) up to August 26, 2025, and by pooling results of studies examining fluoride exposure and its associations with bone health outcomes, namely fracture risk and BMD. We also conducted stratified analyses by sex, age, and fracture site. This study is registered in PROSPERO (CRD42022321899). We included 37 studies published between 1945 and 2024. 10 pertained to bone density only; 19 to bone fractures only; and eight to both outcomes. We found a non-linear, positive relation between fluoride exposure and fracture risk, with an indication of an approximate threshold around 1.5 mg/L of fluoride in drinking water and a nearly linear increasing fracture risk above that concentration (risk ratios of 1.06, 1.19 and 1.35 at 2.0, 3.0 and 4.0 mg/L, respectively, compared to null exposure). Sex-specific dose-response analyses, available only for fragility fractures, indicated an effect in females but little or nothing in males. The association between fluoride and BMD was inconsistent, showing opposite trends for different bone sites (hip and spine) and amounts of exposure, and by sex. Among females aged over 50 years, an association of drinking water fluoride with fragility fracture risk started as early as around 0.5 mg/L (risk ratio of 1.26 at 1.0 mg/L). This study indicates increased risk of fractures with fluoride exposure > 1.5 mg/L in drinking water, with an enhanced susceptibility in postmenopausal females. These findings, which appear consistent with those yielded by recent pooled analysis related to other endpoints in children, may be helpful in assessing the risk-benefit profile for fluoride exposure. not applicable.

The World Health Organization (WHO) commissioned 12 systematic reviews (SR) and meta-analyses (MA) on health effects of exposure to radiofrequency electromagnetic fields (RF-EMF). The health outcomes selected for those reviews (cancer, electromagnetic hypersensitivity, cognitive impairment, birth outcomes, male fertility, oxidative stress, and heat-related effects) were based on a WHO-conducted international survey. The SR of the studies of cancer in laboratory animal studies was the only one that did not include a MA, because those authors considered it inappropriate due to methodological differences among the available studies, including differences in exposure characteristics (carrier frequency, modulation, polarization), experimental parameters (hours/day of exposure, duration of exposure, exposure systems), and different biological models. MAs in all the other SRs suffered from relatively few primary studies available for each MA (sometimes due to excessive subgrouping), exclusion of relevant studies, weaknesses in many of the included primary studies, lack of a framework for analyzing complex processes such as those involved in cognitive functions, and/or high between-study heterogeneity. Due to serious methodological flaws and weaknesses in the conduct of the reviews and MAs on health effects of RF-EMF exposure, the WHO-commissioned SRs cannot be used as proof of safety of cell phones and other wireless communication devices. However, the animal cancer SR, which was rated as “high certainty of evidence” for heart schwannomas and “moderate certainty of evidence” for brain gliomas, provided quantitative information that could be used to set exposure limits based on reducing cancer risk. The multiple and significant dose-related adverse effects found in the SRs on male fertility and pregnancy and birth outcome should also serve as the basis for policy decisions to lower exposure limits and reduce human reproductive risks. The report of harmful effects (e.g., cancer, reproductive toxicity, etc.) at doses below the adverse health effect threshold claimed by ICNIRP demonstrates that current exposure limits to RF-EMF, which were established by applying arbitrary uncertainty factors to their putative adverse threshold dose, lack scientific credibility.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12940-025-01220-4.

Per- and polyfluoroalkyl substances (PFAS) are a large class of synthetic chemicals with ubiquitous human exposure. Maternal PFAS exposure has been linked with adverse birth outcomes, but their associations with preterm birth (PTB) remained ambiguous. To assess the associations of individual and mixed PFAS exposure with preterm birth (PTB) and its subtypes (spontaneous and iatrogenic), a nested case-control study involving 177 PTB cases and 531 controls was conducted in Shanghai, China. Serum concentration of seven PFAS were measured in early pregnancy via ultrahigh-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). PTB, gestational weeks and birth weight were obtained from electronic medical record system. Conditional logistic regression and restricted cubic spline regression (RCS) were used for individual assessment. Weighted quantile sum (WQS) regression, quantile-based g-computation (QGC), and Bayesian kernel machine regression (BKMR) were conducted for PFAS mixture. Subtype analysis and sex stratified analysis were further examined. Both individually and in mixtures, significant associations were observed between elevated PFAS concentrations and increased PTB risk, along with reduced gestational weeks and lower birth weight. The WQS, QGC, and BKMR identified perfluorooctanoic acid (PFOA), per-fluorononanoic acid (PFNA), and perfluoroundecanoic acid (PFUnDA) as the major contributors, with PFOA being particularly significant. Moreover, higher risks of PFAS-associated PTB were observed in the iatrogenic PTB subgroup and pregnant women with male infants. Maternal exposure to PFAS, whether individually or in mixtures, was significantly associated with increased risk of PTB. These associations might be subtype-specific and sex-specific. Further research is needed to validate our results and elucidate the underlying mechanisms.

BackgroundAcetaminophen is the most commonly used over-the-counter pain and fever medication taken during pregnancy, with > 50% of pregnant women using acetaminophen worldwide. Numerous well-designed studies have indicated that pregnant mothers exposed to acetaminophen have children diagnosed with neurodevelopmental disorders (NDDs), including autism spectrum disorder (ASD) and attention-deficit/hyperactivity disorder (ADHD), at higher rates than children of pregnant mothers who were not exposed to acetaminophen.MethodsWe applied the Navigation Guide methodology to the scientific literature to comprehensively and objectively examine the association between prenatal acetaminophen exposure and NDDs and related symptomology in offspring. We conducted a systematic PubMed search through February 25, 2025, using predefined inclusion criteria and rated studies based on risk of bias and strength of evidence. Due to substantial heterogeneity, we opted for a qualitative synthesis, consistent with the Navigation Guide’s focus on environmental health evidence.ResultsWe identified 46 studies for inclusion in our analysis. Of these, 27 studies reported positive associations (significant links to NDDs), 9 showed null associations (no significant link), and 4 indicated negative associations (protective effects). Higher-quality studies were more likely to show positive associations. Overall, the majority of the studies reported positive associations of prenatal acetaminophen use with ADHD, ASD, or NDDs in offspring, with risk-of-bias and strength-of-evidence ratings informing the overall synthesis.ConclusionsOur analyses using the Navigation Guide thus support evidence consistent with an association between acetaminophen exposure during pregnancy and increased incidence of NDDs. Appropriate and immediate steps should be taken to advise pregnant women to limit acetaminophen consumption to protect their offspring’s neurodevelopment.

Background and objectiveTo provide guidance on management strategies for chronic obstructive pulmonary disease (COPD), this study systematically analyzed the burden of the disease due to ozone (O3) exposure in adults aged ≥ 65 years.MethodsData from the Global Burden of Disease Study 2021 were used to analyse trends in the age-standardized mortality rate (ASMR) for O3-related COPD in the elderly (≥ 65 years). Age-period-cohort (APC) model was used to analyse independent age, period and cohort effects. Spearman's correlation coefficient assessed the relationship between ASMR and socio-demographic index (SDI). Decomposition analysis decomposed the drivers of change. Cross-country inequality analysis assessed health inequalities between countries. Frontier analysis estimated optimal health outcomes.ResultsFrom 1990 to 2021, the number of O3-related COPD deaths in the elderly increased from 0.187 to 0.420 million globally. Male ASMR was higher than female ASMR and tended to decrease, whereas female adults ≥ 90 years of age had increased ASMR. ASMR is decreasing in 93 countries and increasing in 78 countries. The global burden of disease was largely driven by population and ageing, but low and low-middle SDI regions were positively affected by ageing, population and epidemiological changes. Global health inequalities remained pronounced, particularly in lower-developed countries. Frontier analyses also showed that countries and regions with lower levels of development had greater potential to improve the burden.ConclusionDespite an overall reduction in the disease burden, O3-related COPD mortality remains a major health threat to the elderly, particularly in less developed countries and regions.