International Journal of Environmental Epidemiology
ISSN: 3079-2746 (Print)
ISSN: 3079-2754 (Online)
Source-specific ambient particulate matter and risk of incident lung cancer: evidence from a Northern Swedish cohort
Objective: To estimate the association between source-specific ambient particulate matter concentrations and lung cancer incidence in a northern Sweden cohort. Methods: Participants in the Västerbotten Intervention Programme cohort from Northern Sweden were recruited between January 1990 and December 2014 and followed until lung cancer diagnosis. Exposure to total particulate matter with aerodynamic diameter ≤ 10 µm (PM10) and ≤ 2.5 µm (PM2.5) as well as source-specific particulate matter (PM) concentrations from traffic (PM10-traffic), exhaust (PM2.5-exhaust) and wood burning (PM2.5-wood burning) was estimated at each participant’s home address using dispersion models with high spatial resolution (down to 35 × 35 m2). Cox regression models were used to assess hazard ratios (HRs) and 95% Confidence Intervals (CIs) for the association between ambient particulate matter exposure and lung cancer incidence, adjusted for relevant potential confounding factors. Results: During 421,466 person-years of follow-up, 253 incident cases of lung cancer were observed. The risk estimates changed considerably when adjusting for individual-level baseline covariates and area level socioeconomic status. In adjusted two-pollutant models, HRs for incident lung cancer in the highest exposure tertile (tertile 3) compared to the lowest (tertile 1) were 1.15 (95% CI: 0.77–1.71) for PM10-traffic, 1.15 (95% CI: 0.76–1.74) for PM2.5-exhaust, and 1.15 (95% CI: 0.77–1.71) for PM2.5-wood burning. Conclusions: Increased risks for lung cancer were estimated to be associated with long-term exposure to PM10-traffic, PM2.5-exhaust, and PM2.5-wood burning. However, since these associations were not statistically significant and did not always appear linear, further studies are needed.
GPS-derived outdoor time and associated vitamin D status
Background: Vitamin D is essential for health and sunlight (ultraviolet radiation band B (UVB) radiation) is a major source. However, individual sunlight exposure is difficult to measure, limiting our ability to identify people at risk of deficiency and to design effective interventions. Therefore, to address limitations of self-reported data, we developed and assessed a method that uses global positioning system (GPS) data to generate individual outdoor time measures relevant to vitamin D synthesis and compared these with serum vitamin D levels. Method: GPS and accelerometer sensors were used to measure time spent outdoors in San Diego adults (n = 130) for an average of 12.6 days. Three categories of outdoor time measures were generated including total outdoor time, number of outdoor “bouts” (distinct periods of outdoor time), and number of days with outdoor bouts. Within these categories, outdoor time was assessed between 10 am–2 pm (peak UVB) and a broader time UVB-relevant time window 8 am–4 pm. Satellite derived daily Ultraviolet (UV) data were used to generate UV weighted versions of the total outdoor time and number of outdoor bout measures. Participants also completed 24-hour food recalls and provided fasting blood samples. Adjusted generalized linear regression models were estimated for associations of each exposure measure with serum vitamin D level. Results: Across all GPS-derived exposure metrics, point estimates were consistently positive, indicating a uniform directional pattern in which greater outdoor time was associated with higher serum vitamin D concentrations, although most confidence intervals included the null. In sensitivity analyses excluding participants who reported taking vitamin D supplements, this pattern persisted. Two measures of longer outdoor exposure provided stronger evidence of an association: the number of 45-minute bouts between 10 am and 2 pm (β = 4.36, 95% CI 0.32 to 8.40) and the number of days with a 45-minute bout (β = 4.38, 95% CI 0.16 to 8.59). In both cases, the confidence intervals did not include the null. More days with shorter bouts also showed a relatively large point estimate, though with substantial imprecision. UV-weighted exposure metrics did not outperform the simpler GPS-derived time‑based measures. Conclusion: GPS-derived outdoor time measures, including those weighted by satellite-derived daily UV, demonstrated consistent positive associations with vitamin D levels, with the strongest evidence observed for longer exposures during peak UVB periods. These findings indicate that simple, time-based GPS metrics and their UV-weighted variants may provide practical and informative indicators of UVB-relevant exposure patterns in real-world settings.
Seminal plasma trace elements: reliability as biomarkers and associations with sperm quality in male IVF patients
Studies of non-occupational exposure to trace elements (TE) and semen quality have had inconsistent results, and few studies have accounted for temporal variability or TE mixtures. To help address the data gap, we quantified associations between seminal plasma (SP) trace element concentrations and sperm quality measures among male partners of in vitro fertilization patients. We collected semen samples from 27 male partners an average of 8.6 days prior to the day of oocyte retrieval (time 1), and from 35 male partners on the day of oocyte retrieval (time 2). We determined concentrations of 14 TEs in SP using inductively coupled plasma-tandem mass spectrometry. We used linear mixed-effects regression to estimate associations between individual TEs, expressed as the change in sperm quality between the 25th and 75th percentiles of trace element distributions, adjusted for age, days between specimen collections, racial identity, recent seafood consumption, and cigarette smoking. We used principal component analysis (PCA) to estimate associations with TE mixtures at time 2. We found positive associations between SP Se and sperm concentration (%change = 47.75%; 95% CI: 4.20, 85.65) and motile sperm concentration (%change = 44.30%; 95% CI: 5.10, 88.75), and similar associations for SP As (%change = 30.50%; 95% CI: 6.85, 54.15 and %change = 25.15%, 95% CI: 12.55, 30.35, respectively). The PCA mixture of higher SP Cd, As, and Mo and lower Cu and Se suggests a pattern of poor sperm quality, though the associations were not statistically significant. Our findings underscore the importance of considering temporal variability of seminal plasma TE concentrations and suggest potentially important associations between exposure to essential TEs and semen quality which should be targeted for further investigation, including Se and As.
Human health risks of waste incinerators: a narrative review of studies on municipal, hazardous and medical waste incineration
This narrative review synthesizes evidence on human health risks linked to emissions from municipal, hazardous and medical waste incinerators up to August 2025. For the search of information, the databases PubMed, Scopus, Web of Science, and Google Scholar were used. The analysis reveals meaningful differences in health outcomes depending on the age and emission control technology of facilities. Evidence from older, high-emission incinerators indicates elevated cancer risks, particularly for soft tissue sarcoma, non-Hodgkin’s lymphoma, and respiratory cancers in exposed communities. The evidence for adverse reproductive outcomes, including birth defects and adverse birth outcomes, is limited and inconsistent. Respiratory disease and symptoms have been reported in some populations living near older incinerators. Workers at incineration facilities show consistent evidence of elevated exposure to carcinogenic compounds. In contrast, studies on modern waste-to-energy plants with advanced emission controls show substantially diminished or limited health risks. However, the evidence base for newer facilities remains relatively small, and long-term health effects are not yet fully established. Major methodological limitations include crude exposure assessment (reliance on residential proximity), inadequate control for confounding factors, ecological study designs, and heterogeneity in study methods. This review highlights the critical importance of technological advancement in reducing health risks, while underscoring the need for continued surveillance, especially in regions with aging infrastructure or inadequate regulatory oversight.
Phthalate exposure and all-cause and cause-specific mortality in overweight and obese adults: a national cohort study
Importance: Phthalate exposure has been found to be associated with an increased risk of obesity. It remains unknown whether exposure to phthalates further impact the health of individuals who are already obese. Objective: To examine the risk of mortality associated with phthalate exposure among individuals with overweight and obesity. Design: A nationally representative sample of adults aged 40 years or older who participated in the US National Health and Nutrition Examination Survey 2001–2010 and provided urine samples for phthalate metabolite measurements. These participants were linked to mortality data from the survey date through December 31, 2019. Exposures: Phthalate metabolites in urine samples were measured by high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry. Main Outcome Measures: Mortality from all causes, cardiovascular disease (CVD), and cancer. Results: This cohort study included 3,845 adults aged 40 years or older (mean age 56.5 [0.3] years). During 46,261 person-years of follow-up (median 12 years; maximum 19 years), 990 deaths occurred, of which 304 were from CVD and 246 were from cancer. Elevated concentrations of high-molecular-weight (HMW) urinary phthalate metabolites and di-2-ethylhexylphthalate (DEHP) were associated with a 46% and 36% increased risk of all-cause mortality, respectively. Regarding low-molecular-weight (LMW) phthalates, higher exposure was specifically linked to a 43% excess risk of CVD mortality. Bayesian kernel machine regression (BKMR) analyses indicated a 7.3% increase in all-cause mortality associated with phthalate co-exposure (75th vs. 50th percentile). Conclusions and Relevance: In this nationally representative study, phthalate co-exposure was significantly positively associated with all-cause and CVD mortality among individuals with overweight and obesity. Higher levels of HMW and DEHP exposure were linked to increased all-cause mortality, while high LMW exposure was associated with elevated CVD mortality. Further studies are necessary to confirm these findings and investigate the underlying mechanisms.
Parental preconception exposure to residential outdoor neighbourhood environments and adverse pregnancy and birth outcomes: a scoping review
Background: Preconception exposure to residential outdoor neighbourhood environments can influence perinatal outcomes by influencing fertility, gamete quality and foetal development through mechanisms such as oxidative stress, epigenetics and inflammation. Following our published protocol, this scoping review aims to synthesize the available evidence and identify gaps in the current understanding of this topic. Methods: We searched four databases (Cumulative Index to Nursing and Allied Health Literature, Ovid Medline, Ovid Embase and Scopus) for peer-reviewed publications on 20 December 2023. The search was restricted to English, without other restrictions. Two reviewers independently screened titles, abstracts and full texts. Findings were narratively synthesised. Results: We identified 82 eligible studies since 2010, all but one from upper-middle-or high-income countries. The largest proportion (43%) comprised retrospective cohort studies, with number of studies published since 2020 trending upwards. Although preconception was usually defined as the three months before pregnancy, most studies assigned these exposures using pregnancy or birth addresses, assuming residential stability since preconception. Among included studies, exposure to PM2.5 was associated with an increased risk of gestational diabetes mellitus (GDM), while PM10 was linked to birth defects. However, most exposure-outcome associations were inconsistent across included studies. The literature suggested the strongest consistency for PM10-birth defects associations, while evidence for O3-GDM associations was inconclusive. Research on other outdoor environmental factors, such as noise, light pollution, weather, built and natural environments, was lacking. Conclusions: Our review found that the existing evidence base is geographically skewed, concentrated on air pollution exposures, and notably lacking in research on paternal exposures. To advance the field, future studies should adopt more precise exposure assessments and expand the range of environmental factors, geographical diversity, and paternal exposure research.
