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Toxicological studies of single chemicals overlook the real-world complexity of human exposure, where multiple compounds may interact to disrupt biological processes such as endocrine signaling. Moreover, the chemical exposome, the sum of an individual's chemical burden, varies markedly between people, yet its biological implications remain unclear. To address this gap, we reconstructed individualized human chemical exposomes to assess their effects on estrogen receptor (ER) activity. Sixteen exposomes comprising 24 persistent organic pollutant (POP) were derived from blood profiles of participants in the Swedish Västerbotten Intervention Programme. Using automated, non-contact acoustic liquid dispensing, we reconstructed 14 personalized mixtures (PMs) reflecting individual blood compositions and two formulated mixtures (FM) representing the cohort's median and maximum population exposure levels. ER activity was assessed in VM7Luc4E2 cells using a high-throughput 384-well adaption of the OECD No. 455 assay at 1×, 10× and 100× blood concentrations. While most individual POPs showed no or weak ER activity, three mixtures induced ER agonism. The PM-High, corresponding to the individual with the highest total POP levels, and the FM-Median activated the ER at 100×, while the FM-Maximum induced activation at 10× and 100×. Removing β-HCH and trans-nonachlor from the active mixtures abolished or reduced ER activity. Co-treatment with physiological estradiol levels increased ER responses in six mixtures, PM#1 (1× and 10×), PM#4 (100×), PM#8 (10×), PM#9 (100×), PM#10 (1×) and the FM-Median (1×), indicating potentiation of endogenous hormonal signaling. Overall, this study reveals endocrine activity in real-world POP mixtures and advances high-throughput screening as a scalable approach for individualized exposome-based health risk evaluation.

Previous studies have found a markedly reduced risk of cancer among Huntington’s disease (HD) patients with CAG ≥ 40, but data on cancer risk at shorter repeat numbers are lacking. The study includes 8149 subjects from Northern Sweden Health and Disease Study. Genotyping yielded a large number of intermediate allele carriers (IA, CAGn 27–35, (n = 497), normal alleles (CAGn 17–26,n = 6584), short alleles (CAG ≤ 16, n = 169) and 31 subjects with > 35 repeats, including reduced penetrance alleles (36–39; not guaranteed to suffer HD symptoms during a normal lifespan) and HD alleles > 39. Cancer diagnoses were retrieved from the Swedish Cancer Registry and the Hospital Discharge Registry and death certificates. We used Kaplan-Meier curves and Cox proportional hazard models to estimate the time to cancer, on strata of the population created by CAG repeat number intervals. Smoking status, BMI, as well as alcohol consumption were included in the models. 2735 participants (33.6%) had ≥ 1 cancer type. The Hazard-Ratio (HR) for IA carriers compared with normal alleles was similar, 0.97 CI 0.82–1.15). The reduced penetrance allele group (CAGn 36–39, n = 29) had HR of 0.54 CI 0.22–1.30 similar to what has been reported with a full penetrance allele. Intermediate allele carriers as a group did not have a reduced risk of cancer. It remains possible that reduced penetrance alleles confer lower risk of cancer, with signs of a dose-dependent protective effect of CAG repeat length. The latter finding needs to be confirmed in even larger cohorts as these repeat numbers are relatively rare.

Systemic Sonic Hedgehog (Shh) signaling is increasingly recognized as a potential regulator of adult metabolic homeostasis, yet its role in human disease remains poorly defined. In this study, we measured plasma Shh levels in two large Swedish cohorts to assess their associations with common non-communicable diseases, with a particular focus on type 2 diabetes mellitus (T2DM) and metabolic dysfunction. A population-based screen of 735 individuals revealed substantial inter-individual variability in Shh levels, with elevated levels associated with T2DM and hypertension in females but not in males. These findings were validated in a nested case–control study, where Shh levels were significantly higher in T2DM females compared to matched controls. Correlation analyses showed that Shh levels were associated with insulin resistance in both sexes but reflected different disease states with early compensatory insulin secretion in males and late β-cell dysfunction in females. Mechanistic studies using human intestinal organoids demonstrated that Shh secretion is induced by the combination of glucose and insulin, suggesting the intestine as a nutrient-responsive source of the systemic Shh. Together, these results identify Shh as a sexually dimorphic marker of metabolic dysfunction and support its functional role in glycemic control and metabolic disease.

Key features: 

• The Northern Sweden Health and Disease Study (NSHDS) was initiated in the mid-1980s. The NSHDS is a population-based prospective longitudinal cohort comprising >140 000 participants in the two northernmost regions in Sweden, Norrbotten and Västerbotten, with >240 000 blood samples and 1.5 million person-years of follow-up.
• The NSHDS includes three sub-cohorts: the Västerbotten Intervention Programme (VIP), the expanded Northern Sweden Monitoring of Trends and Determinants of Cardiovascular Disease (MONICA) Study, and the Mammography Screening Project (MSP). The VIP is both a community-based cardiometabolic intervention programme encouraging healthy lifestyle (targeting individuals 40, 50, and 60 years of age), and a corresponding research cohort. The MONICA is an observational study focusing on cardiovascular disease and its associated risk factors, recruiting individuals aged 25–74 years. The MSP recruited women attending mammography during 1995–2006. The NSHDS median participation age is 50 years (53% women).
• Most participants contribute data on health, lifestyle, anthropometric measures, blood pressure, blood lipids, and glucose tolerance, along with research blood samples that are fractionated, frozen within an hour of collection, and stored at –80°C. Linkage to registries, clinical cohorts, and biological tissue archives facilitates studies of well-characterized participants (often combined with intervention studies).
• Collaborations are encouraged. Additional information can be found at: info.brs@umu.se; https://www.umu.se/en/biobank

Aims: Plasminogen activator inhibitor-1 (PAI-1) is the main inhibitor of the fibrinolytic system and is mainly secreted from adipose tissue. It is associated with cardiovascular disease and has also been considered a possible early risk marker for type 2 diabetes. Here, we present the results of a large prospective study investigating PAI-1 levels in relation to incident type 2 diabetes mellitus.

Methods: We conducted a prospective incident case-referent study within the Västerbotten Intervention Programme (VIP). Data on cardiovascular risk factors, fasting plasma glucose (FPG) and 2-hour plasma glucose (2-hPG) were collected at baseline health examination 1990–2005. Blood samples were collected and stored for future analyses. Participants were followed and 484 cases developed type 2 diabetes. Referents without type 2 diabetes were matched for sex, age, and year of participation, n = 484. Baseline plasma samples were analysed for PAI-1. Subgroup analysis was performed for 201 cases and 201 matched referents with normal baseline glucose levels (FPG < 6.1 and 2hPG < 8.9 mmol/L).

Results: Elevated baseline levels of PAI-1 were associated with incident type 2 diabetes after adjustments for BMI, family history of diabetes, smoking status, hypertension, FPG and 2hPG (PAI-1; OR = 1.87, 95% CI: 1.06–3.29). A similar result was shown in the subgroup analysis with 201 participants who had normal glucose levels at time of the health examination (PAI-1; OR = 2.68, 95% CI: 1.03–6.95).

Conclusions: Elevated PAI-1 levels in non-diabetic persons precede the manifestation of type 2 diabetes and can be detected before an elevation of FPG or 2-hPG is observed.

Aims: Helicobacter pylori (H. pylori) and its cytotoxin-associated gene A (CagA) have been associated with myocardial infarction (MI), but existing data are conflicting possibly due to limitations in study designs and lack of data on important confounders. The aim of this study was to determine whether H. pylori or CagA seropositivity is associated with incident MI, including MI phenotypes, and to describe temporal trends.

Methods: We used the Northern Sweden Health and Disease study, a prospective biobank with data from residents enrolled in a population-based cohort from health examinations between 1986 and 2006. A total of 826 first time MI cases with available blood samples from their index health examination were identified up to 2006. Each case was 1:2 matched with controls by age, sex, sample date and geographical area. Blood samples were analysed using ELISA to determine seroprevalence of H. pylori and CagA, which were then used to study the association with incident MI.

Results: The median age at baseline was 50 years, and 71% of participants were male. Seroprevalence of H. pylori and CagA was 46.5% and 32.1% in cases, respectively, compared to 43.7% and 30.6% in controls. Overall, H. pylori prevalence decreased over the study period. After multivariable adjustments, no significant association was observed between H. pylori seropositivity and incident MI (odds ratio: 1.15, 95% CI 0.94–1.42) nor between CagA-positive H. pylori and incident MI.

Conclusion: In a Swedish population-based cohort, no significant association was observed between H. pylori or CagA seropositivity and incidence of MI.

We assessed temporal changes of PFAS and associations with T2DM over a period of 30 years in a nested case–control study with repeated measurements. Logistic regression was used to assess associations between 11 PFAS and T2DM at five time-points in 116 cases and 139 controls (3 pre- and 2 post-diagnostic time-points in cases). Mixed linear models were applied to assess if changes in PFAS were related to T2DM status. In the pre-diagnostic time-point T3 (2001), future cases had higher concentrations of PFHpA, PFNA, PFHxS and PFHpS compared to controls. In the post-diagnostic time point T5 (2015/16), PFNA and PFOS were higher in prevalent cases. PFHxS and PFHpS were positively associated with future T2DM at the pre-diagnostic time-point T3, whereas PFTrDA were inversely associated with future T2DM at T1 (1986/87) and prevalent T2DM at T4 (2007/8). Temporal changes in PFAS across the study period showed that cases experienced a greater increase in pre-diagnostic concentrations of PFHpA, PFTrDA, PFHxS and PFOSA, as well as a larger post-diagnostic decrease in PFOSA, compared to controls. This study is the first to show that temporal changes in PFAS are associated with T2DM status for certain PFAS, and associations between PFAS and T2DM vary according to sample year.

For comprehensive chemical exposomics in blood, analytical workflows are evolving through advances in sample preparation and instrumental methods. We hypothesized that gas chromatography-high-resolution mass spectrometry (GC-HRMS) workflows could be enhanced by minimizing lipid coextractives, thereby enabling larger injection volumes and lower matrix interference for improved target sensitivity and nontarget molecular discovery. A simple protocol was developed for small plasma volumes (100-200 μL) by using isohexane (H) to extract supernatants of acetonitrile-plasma (A-P). The HA-P method was quantitative for a wide range of hydrophobic multiclass target analytes (i.e., log K_ow > 3.0), and the extracts were free of major lipids, thereby enabling robust large-volume injections (LVIs; 25 μL) in long sequences (60-70 h, 70-80 injections) to a GC-Orbitrap HRMS. Without lipid removal, LVI was counterproductive because method sensitivity suffered from the abundant matrix signal, resulting in low ion injection times to the Orbitrap. The median method quantification limit was 0.09 ng/mL (range 0.005-4.83 ng/mL), and good accuracy was shown for a certified reference serum. Applying the method to plasma from a Swedish cohort (n = 32; 100 μL), 51 of 103 target analytes were detected. Simultaneous nontarget analysis resulted in 112 structural annotations (12.8% annotation rate), and Level 1 identification was achieved for 7 of 8 substances in follow-up confirmations. The HA-P method is potentially scalable for application in cohort studies and is also compatible with many liquid-chromatography-based exposomics workflows.

Chemical risk assessments typically focus on single substances, often overlooking real-world co-exposures to chemical mixtures. Mixture toxicology studies using representative mixtures can reveal potential chemical interactions, but these do not account for the unique chemical profiles that occur in the blood of diverse individuals. Here we used the H295R steroidogenesis assay to screen personalized mixtures of 24 persistent organic pollutants (POPs) for cytotoxicity and endocrine disruption. Each mixture was reconstructed at a human exposure relevant concentration (1×), as well as at 10- and 100-fold higher concentration (10×, 100×) by acoustic liquid handling based on measured blood concentrations in a Swedish cohort. Among the twelve mixtures tested, nine mixtures decreased the cell viability by 4–18%, primarily at the highest concentration. While the median and maximum mixtures based on the whole study population induced no measurable effects on steroidogenesis at any concentration, the personalized mixture from an individual with the lowest total POPs concentration was the only mixture that affected estradiol synthesis (35% increase at the 100× concentration). Mixtures reconstructed from blood levels of three different individuals stimulated testosterone synthesis at the 1× (11–15%) and 10× concentrations (12–16%), but not at the 100× concentration. This proof-of-principle personalized toxicity study illustrates that population-based representative chemical mixtures may not adequately account for the toxicological risks posed to individuals. It highlights the importance of testing a range of real-world mixtures at relevant concentrations to explore potential interactions and non-monotonic effects. Further toxicological studies of personalized contaminant mixtures could improve chemical risk assessment and advance the understanding of human health, as chemical exposome data become increasingly available.

OBJECTIVES: The authors aimed to evaluate whether blood cadmium (B-Cd), lead (B-Pb) and mercury (B-Hg) in children differ regionally in 9 countries, and to identify factors correlating with exposure.

MATERIAL AND METHODS: The authors performed a cross-sectional study of children aged 7-14 years, living in 2007-2008 in urban, rural, or potentially polluted ("hot spot") areas (ca. 50 children from each area, in total 1363 children) in 6 European and 3 non-European countries. The authors analyzed Cd, Pb, and total Hg in blood and collected information on potential determinants of exposure through questionnaires. Regional differences in exposure levels were assessed within each country.

RESULTS: Children living near industrial "hot-spots" had B-Cd 1.6 (95% CI: 1.4-1.9) times higher in the Czech Republic and 2.1 (95% CI:1.6-2.8) times higher in Poland, as compared to urban children in the same countries (geometric means [GM]: 0.13 μg/l and 0.15 μg/l, respectively). Correspondingly, B-Pb in the "hot spot" areas was 1.8 (95% CI: 1.6-2.1) times higher than in urban areas in Slovakia and 2.3 (95% CI: 1.9-2.7) times higher in Poland (urban GM: 19.4 μg/l and 16.3 μg/l, respectively). In China and Morocco, rural children had significantly lower B-Pb than urban ones (urban GM: 64 μg/l and 71 μg/l, respectively), suggesting urban exposure from leaded petrol, water pipes and/or coal-burning. Hg "hot spot" areas in China had B-Hg 3.1 (95% CI: 2.7-3.5) times higher, and Ecuador 1.5 (95% CI: 1.2-1.9) times higher, as compared to urban areas (urban GM: 2.45 μg/l and 3.23 μg/l, respectively). Besides industrial exposure, traffic correlated with B-Cd; male sex, environmental tobacco smoke, and offal consumption with B-Pb; and fish consumption and amalgam fillings with B-Hg. However, these correlations could only marginally explain regional differences.

CONCLUSIONS: These mainly European results indicate that some children experience about doubled exposures to toxic elements just because of where they live. These exposures are unsafe, identifiable, and preventable and therefore call for preventive actions.