Faculty Bibliography

BACKGROUND:The associations between different types of diabetes, characterized by distinct pathophysiology and genetic architecture, and pancreatic ductal adenocarcinoma (PDAC) risk are not understood. METHODS:We investigated associations of genetic susceptibility to type 2 diabetes (T2D), eight T2D mechanistic clusters, type 1 diabetes (T1D), and maturity-onset diabetes of the young (MODY) with PDAC risk. We used genome-wide association study (GWAS) summary-level statistics for T2D (242,283 cases, 1,569,734 controls), T1D (18,942 cases, 501,638 controls), and PDAC (10,244 cases and 360,535 controls) in individuals of European ancestry. RESULTS:Two-sample Mendelian randomization (MR) using the Robust Adjusted Profile Score (MR-RAPS) method indicated that genetically predicted T2D was associated with PDAC risk (OR = 1.10; 95% CI 1.05-1.15), particularly the T2D obesity (OR = 1.28; 95% CI 1.15-1.42) and lipodystrophy (OR = 1.25; 95% CI 1.03-1.51) clusters. No association was observed for T1D with PDAC risk (OR = 1.01; 95% CI 0.99-1.02). Pathway/gene-set analysis using the summary-based Adaptive Rank Truncated Product (sARTP) method revealed a significant association between the MODY gene-sets and PDAC risk (P = 1.5 × 10-8), which remained after excluding 20 known PDAC GWAS loci (P = 7.6 × 10-4). HNF1A, FOXA3, and HNF4A were the top contributing genes after excluding the previously identified GWAS loci regions. CONCLUSIONS:Our results from this genetic association study support that T2D, particularly the obesity and lipodystrophy mechanistic clusters, and MODY genomic susceptibility regions play a role in the etiology of PDAC.

BACKGROUND/UNASSIGNED:While there is wide evidence on concentrations of cytokines in patients attending health care facilities, evidence is scant on physiological, basal concentrations of cytokines in the general population and across sociodemographic groups, as well as on their potential stability over time. Furthermore, from a public health perspective it is remarkable that no studies have analyzed intraindividual changes in such concentrations from before the COVID-19 pandemic until its outbreak. OBJECTIVES/UNASSIGNED:To investigate: (a) prepandemic concentrations of cytokines and immunoglobulins to viral exposures in a general, non-institutionalized population, and their associated sociodemographic variables; (b) the intraindividual change in such concentrations between a prepandemic period (2016-17) and the initial pandemic period (2020-21); and (c) whether such change was similar in participants who in 2020-21 were SARS-CoV-2 seronegative and seropositive, and between participants who did and did not develop COVID-19. METHODS/UNASSIGNED:We conducted a prospective cohort study in 240 individuals from the general population of Barcelona, Spain. Thirty cytokines and 31 immunoglobulins were measured in paired serum samples collected in 2016-17 and 2020-21 in the same individuals. RESULTS/UNASSIGNED:The median value of the relative intraindividual change in cytokine concentrations between 2016 and 2020 was <15% for 29 of the 30 cytokines. A substantial number of participants had an intraindividual increase or decrease ≥15% in some cytokines. No major differences in intraindividual changes of cytokine and immunoglobulin levels between 2016 and 2020 were observed between participants who did and did not develop COVID-19. CONCLUSION/UNASSIGNED:We provide novel information on physiological, basal ex-vivo concentrations of cytokines and immunoglobulins in a general population, which should be relevant for clinical practice and public health. Intraindividual changes in cytokines and immunoglobulins during the 4 years from 2016-17 to 2020-21 were moderate, and they did not differ between participants who in 2020-21 were SARS-CoV-2 seropositive and seronegative, nor between participants who did and did not develop COVID-19 disease. These findings are also novel and relevant for medicine and public health. In particular, the stability in the biomarkers is relevant to assess the role of the immunological and inflammatory state (measured through baseline levels of cytokines and immunoglobulins) in the development of SARS-CoV-2 seropositivity and COVID-19 disease, as well as in the susceptibility to other infections and pathologies.

Randomized trials can take more explanatory or more pragmatic approaches. Pragmatic studies, conducted closer to real-world conditions, assess treatment effectiveness while considering factors like protocol adherence. In these studies, intention-to-treat (ITT) analysis is fundamental, comparing outcomes regardless of the actual treatment received. Explanatory trials, conducted closer to optimal conditions, evaluate treatment efficacy, commonly with a per protocol (PP) analysis, which includes only outcomes from adherent participants. ITT and PP are strategies used in the conception, design, conduct (protocol execution), analysis, and interpretation of trials. Each serves distinct objectives. While both can be valid, when bias is controlled, and complementary, each has its own limitations. By excluding nonadherent participants, PP analyses can lose the benefits of randomization, resulting in group differences in factors (influencing adherence and outcomes) that were present at baseline. Additionally, clinical and social factors affecting adherence can also operate during follow-up, that is, after randomization. Therefore, incomplete adherence may introduce postrandomization confounding. Conversely, ITT analysis, including all participants regardless of adherence, may dilute treatment effects. Moreover, varying adherence levels could limit the applicability of ITT findings in settings with diverse adherence patterns. Both ITT and PP analyses can be affected by selection bias due to differential losses and nonresponse (ie, missing data) during follow-up. Combining high-quality and comprehensive data with advanced statistical methods, known as g-methods, like inverse probability weighting, may help address postrandomization confounding in PP analysis as well as selection bias in both ITT and PP analyses.

The aim was to investigate the concentrations of some per- and polyfluoroalkyl substances (PFAS) in patients with pancreatic cancer from New York, and to compare them with a group of controls from the general population of the United States. We selected 50 cases of pancreatic cancer from donors to the New York University Pancreatic Biorepository. Controls were selected from the 2017"“18 National Health and Examination Survey sample (n = 167), matched to cases on age, sex, and race and ethnicity. Six PFAS were analyzed in serum samples using high performance liquid chromatography in conjunction with mass spectrometry. PFAS concentrations were categorized into tertiles to explore non-linear associations, and odds ratios (OR) were estimated using conditional logistic regression, adjusting by BMI. Most PFAS were not associated with pancreatic cancer risk. Serum perfluorohexane sulfonic acid (PFHxS) was associated with a decreased risk (OR for upper tertile = 0.24, 95% CI: 0.09, 0.67). In contrast, participants with the highest tertile of perfluoroundecanoic acid (PFUnDA) had a higher risk (OR = 2.60, 95% CI: 1.11, 6.09). Adjusting for BMI did not materially change the results. Study limitations include: in pancreatic cancer patients, blood used to measure PFAS was collected around the time of diagnosis; cases and controls could not be sampled from the same geographic location; slightly different laboratory methods were used to analyze PFAS in cases and controls. Most PFAS studied were not significantly associated with pancreatic cancer, except for PFHxS and PFUnDA, which exhibited opposite trends. Findings and limitations of the present study warrant further investigation with improved study designs and data on complex PFAS mixtures.

OBJECTIVE:To investigate the specific and combined effects of personal concentrations of some per- and polyfluoroalkyl substances (PFAS), other persistent organic pollutants (POPs), and chemical elements -measured in individuals' blood several years before the pandemic- on the development of SARS-CoV-2 infection and COVID-19 disease in the general population. METHODS:We conducted a prospective cohort study in 240 individuals from the general population of Barcelona. PFAS, other POPs, and chemical elements were measured in plasma, serum, and whole blood samples, respectively, collected in 2016-2017. PFAS were analyzed by liquid chromatography-triple quadrupole mass spectrometry. SARS-CoV-2 infection was detected by rRT-PCR in nasopharyngeal swabs and/or antibody serology in blood samples collected in 2020-2021. RESULTS:No individual PFAS nor their mixtures were significantly associated with SARS-CoV-2 seropositivity or COVID-19 disease. Previously identified mixtures of POPs and elements (Porta et al., 2023) remained significantly associated with seropositivity and COVID-19 when adjusted for PFAS (all OR > 4 or p < 0.05). Nine chemicals comprised mixtures associated with COVID-19: thallium, ruthenium, lead, benzo[b]fluoranthene, DDD, other DDT-related compounds, manganese, tantalum, and aluminium. And nine chemicals comprised the mixtures more consistently associated with SARS-CoV-2 seropositivity: thallium, ruthenium, lead, benzo[b]fluoranthene, DDD, gold, and (protectively) selenium, indium, and iron. CONCLUSIONS:The PFAS studied were not associated with SARS-CoV-2 seropositivity or COVID-19. The results confirm the associations between personal blood concentrations of some POPs and chemical elements and the risk of COVID-19 and SARS-CoV-2 infection in what remains the only prospective and population-based cohort study on the topic. Mixtures of POPs and chemical elements may contribute to explain the heterogeneity in the risks of SARS-CoV-2 infection and COVID-19 in the general population.

BACKGROUND:There are conflicting data on whether nonalcoholic fatty liver disease (NAFLD) is associated with susceptibility to pancreatic cancer (PC). Using Mendelian randomization (MR), we investigated the relationship between genetic predisposition to NAFLD and risk for PC. METHODS:Data from genome-wide association studies within the Pancreatic Cancer Cohort Consortium (PanScan; cases n=5090, controls n=8733) and the Pancreatic Cancer Case Control Consortium (PanC4; cases n=4,163, controls n=3,792) were analyzed. We used data on 68 genetic variants with four different MR methods (inverse variance weighting [IVW], MR-Egger, simple median, and penalized weighted median) separately to predict genetic heritability of NAFLD. We then assessed the relationship between each of the four MR methods and PC risk, using logistic regression to calculate odds ratios (ORs) and 95% confidence intervals (CIs), adjusting for PC risk factors, including obesity and diabetes. RESULTS:No association was found between genetically predicted NAFLD and PC risk in the PanScan or PanC4 samples (e.g., PanScan, IVW OR=1.04, 95% CI: 0.88-1.22, MR-Egger OR=0.89, 95% CI: 0.65-1.21; PanC4, IVW OR=1.07, 95% CI: 0.90-1.27, MR-Egger OR=0.93, 95% CI: 0.67-1.28). None of the four MR methods indicated an association between genetically predicted NAFLD and PC risk in either sample. CONCLUSIONS:Genetic predisposition to NAFLD is not associated with PC risk. IMPACT/CONCLUSIONS:Given the close relationship between NAFLD and metabolic conditions, it is plausible that any association between NAFLD and PC might reflect host metabolic perturbations (e.g., obesity, diabetes, or metabolic syndrome) and does not necessarily reflect a causal relationship between NAFLD and PC.

Citizens deserve regulatory changes and policies more sensitive to the current needs of humans, the climate, and nature. In this work we draw on prior experiences of preventable human suffering and economic losses caused by delayed regulation of legacy and emerging pollutants. Heightened awareness of environmental health problems is necessary among health professionals, the media, and citizens' organizations. Improved translation from research to the clinical world and to policy is critical to reduce the population burden of diseases caused by exposure to endocrine disruptors and other environmental chemicals. Numerous lessons can be learned from science-to-policy processes built for "old pollutants" (as persistent organic pollutants, heavy metals, tributyltin), as well as from current trends regarding the regulation of non-persistent chemicals, such as the prototypical endocrine disruptor bisphenol A. We end discussing relevant pieces of the puzzle to tackle the environmental and regulatory challenges faced by our societies.

Knowledge on the role in cancer etiology of environmental exposures as pesticides is a pre-requisite for primary prevention. We review 62 epidemiological studies on exposure to pesticides and cancer risk in humans published from 2017 to 2021, with emphasis on new findings, methodological approaches, and gaps in the existing literature. While much of the recent evidence suggests causal relationships between pesticide exposure and cancer, the strongest evidence exists for acute myeloid leukemia (AML) and colorectal cancer (CRC), diseases in which the observed associations were consistent across several studies, including high quality prospective studies and those using biomarkers for exposure assessment, with some observing dose-response relationships. Though high-quality studies have been published since the IARC monograph on organophosphate insecticides in 2017, there are still gaps in the literature on carcinogenic evidence in humans for a large number of pesticides. To further knowledge, we suggest leveraging new techniques and methods to increase sensitivity and precision of exposure assessment, incorporate multi-omics data, and investigate more thoroughly exposure to chemical mixtures. There is also a strong need for better and larger population-based cohort studies that include younger and non-occupationally exposed individuals, particularly during developmental periods of susceptibility. Though the existing evidence has limitations, as always in science, there is sufficient evidence to implement policies and regulatory action that limit pesticide exposure in humans and, hence, further prevent a significant burden of cancers.

BACKGROUND:Findings and limitations of previous studies on persistent organic pollutants (POPs) and pancreatic cancer risk support conducting further research in prospective cohorts. METHODS:We conducted a prospective case-control study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Participants were 513 pancreatic cancer cases and 1020 matched controls. Concentrations of 22 POPs were measured in plasma collected at baseline. RESULTS:Some associations were observed at higher concentrations of p, p'-DDT, trans-nonachlor, β-hexachlorocyclohexane and the sum of six organochlorine pesticides and of 16 POPs. The odds ratio (OR) for the upper quartile of trans-nonachlor was 1.55 (95% confidence interval 1.06-2.26; P for trend = 0.025). Associations were stronger in the groups predefined as most valid (participants having fasted >6 h, with microscopic diagnostic confirmation, normal weight, and never smokers), and as most relevant (follow-up ≥10 years). Among participants having fasted >6 h, the ORs were relevant for 10 of 11 exposures. Higher ORs were also observed among cases with microscopic confirmation than in cases with a clinical diagnosis, and among normal-weight participants than in the rest of participants. Among participants with a follow-up ≥10 years, estimates were higher than in participants with a shorter follow-up (for trans-nonachlor: OR = 2.14, 1.01 to 4.53, P for trend = 0.035). Overall, trans-nonachlor, three PCBs and the two sums of POPs were the exposures most clearly associated with pancreatic cancer risk. CONCLUSIONS:Individually or in combination, most of the 22 POPs analysed did not or only moderately increased the risk of pancreatic cancer.