Long-term exposure to air pollution has been associated with several adverse health effects including cardiovascular, respiratory diseases and cancers. However, underlying molecular alterations ...remain to be further investigated. The aim of this study is to investigate the effects of long-term exposure to air pollutants on (a) average DNA methylation at functional regions and, (b) individual differentially methylated CpG sites. An assumption is that omic measurements, including the methylome, are more sensitive to low doses than hard health outcomes.
This study included blood-derived DNA methylation (Illumina-HM450 methylation) for 454 Italian and 159 Dutch participants from the European Prospective Investigation into Cancer and Nutrition (EPIC). Long-term air pollution exposure levels, including NO2, NOx, PM2.5, PMcoarse, PM10, PM2.5 absorbance (soot) were estimated using models developed within the ESCAPE project, and back-extrapolated to the time of sampling when possible. We meta-analysed the associations between the air pollutants and global DNA methylation, methylation in functional regions and epigenome-wide methylation. CpG sites found differentially methylated with air pollution were further investigated for functional interpretation in an independent population (EnviroGenoMarkers project), where (N=613) participants had both methylation and gene expression data available.
Exposure to NO2 was associated with a significant global somatic hypomethylation (p-value=0.014). Hypomethylation of CpG island's shores and shelves and gene bodies was significantly associated with higher exposures to NO2 and NOx. Meta-analysing the epigenome-wide findings of the 2 cohorts did not show genome-wide significant associations at single CpG site level. However, several significant CpG were found if the analyses were separated by countries. By regressing gene expression levels against methylation levels of the exposure-related CpG sites, we identified several significant CpG-transcript pairs and highlighted 5 enriched pathways for NO2 and 9 for NOx mainly related to the immune system and its regulation.
Our findings support results on global hypomethylation associated with air pollution, and suggest that the shores and shelves of CpG islands and gene bodies are mostly affected by higher exposure to NO2 and NOx. Functional differences in the immune system were suggested by transcriptome analyses.
•We studied the effects of long-term exposure to air pollutants on DNA methylation.•A consistent global hypomethylation was observed for exposure to ambient NO2 and NOx.•This hypomethylation was observed for CpG island's shores, shelves and gene bodies.•No CpG sites were epigenome-wide significant in a combined analysis of a low and high exposed cohort.
Type 2 diabetes mellitus has been associated with an excess risk of pancreatic cancer, but the magnitude of the risk and the time–risk relationship are unclear, and there is limited information on ...the role of antidiabetic medications.
We analyzed individual-level data from 15 case–control studies within the Pancreatic Cancer Case-Control Consortium, including 8305 cases and 13 987 controls. Pooled odds ratios (ORs) were estimated from multiple logistic regression models, adjusted for relevant covariates.
Overall, 1155 (15%) cases and 1087 (8%) controls reported a diagnosis of diabetes 2 or more years before cancer diagnosis (or interview, for controls), corresponding to an OR of 1.90 (95% confidence interval, CI, 1.72–2.09). Consistent risk estimates were observed across strata of selected covariates, including body mass index and tobacco smoking. Pancreatic cancer risk decreased with duration of diabetes, but a significant excess risk was still evident 20 or more years after diabetes diagnosis (OR 1.30, 95% CI 1.03–1.63). Among diabetics, long duration of oral antidiabetic use was associated with a decreased pancreatic cancer risk (OR 0.31, 95% CI 0.14–0.69, for ≥15 years). Conversely, insulin use was associated with a pancreatic cancer risk in the short term (OR 5.60, 95% CI 3.75–8.35, for <5 years), but not for longer duration of use (OR 0.95, 95% CI 0.53–1.70, for ≥15 years).
This study provides the most definitive quantification to date of an excess risk of pancreatic cancer among diabetics. It also shows that a 30% excess risk persists for more than two decades after diabetes diagnosis, thus supporting a causal role of diabetes in pancreatic cancer. Oral antidiabetics may decrease the risk of pancreatic cancer, whereas insulin showed an inconsistent duration–risk relationship.
Bile acids (BAs) play different roles in cancer development. Some are carcinogenic and BA signaling is also involved in various metabolic, inflammatory and immune-related processes. The liver is the ...primary site of BA synthesis. Liver dysfunction and microbiome compositional changes, such as during hepatocellular carcinoma (HCC) development, may modulate BA metabolism increasing concentration of carcinogenic BAs. Observations from prospective cohorts are sparse. We conducted a study (233 HCC case-control pairs) nested within a large observational prospective cohort with blood samples taken at recruitment when healthy with follow-up over time for later cancer development. A targeted metabolomics method was used to quantify 17 BAs (primary/secondary/tertiary; conjugated/unconjugated) in prediagnostic plasma. Odd ratios (OR) for HCC risk associations were calculated by multivariable conditional logistic regression models. Positive HCC risk associations were observed for the molar sum of all BAs (OR
= 2.30, 95% confidence intervals CI: 1.76-3.00), and choline- and taurine-conjugated BAs. Relative concentrations of BAs showed positive HCC risk associations for glycoholic acid and most taurine-conjugated BAs. We observe an association between increased HCC risk and higher levels of major circulating BAs, from several years prior to tumor diagnosis and after multivariable adjustment for confounders and liver functionality. Increase in BA concentration is accompanied by a shift in BA profile toward higher proportions of taurine-conjugated BAs, indicating early alterations of BA metabolism with HCC development. Future studies are needed to assess BA profiles for improved stratification of patients at high HCC risk and to determine whether supplementation with certain BAs may ameliorate liver dysfunction.
Polyphenols are bioactive compounds with several anticarcinogenic activities; however, human data regarding associations with thyroid cancer (TC) is still negligible. Our aim was to evaluate the ...association between intakes of total, classes and subclasses of polyphenols and risk of differentiated TC and its main subtypes, papillary and follicular, in a European population. The European Prospective Investigation into Cancer and Nutrition cohort included 476,108 men and women from 10 European countries. During a mean follow‐up of 14 years, there were 748 incident differentiated TC cases, including 601 papillary and 109 follicular tumors. Polyphenol intake was estimated at baseline using validated center/country‐specific dietary questionnaires and the Phenol‐Explorer database. In multivariable‐adjusted Cox regression models, no association between total polyphenol and the risks of overall differentiated TC (HRQ4 vs. Q1 = 0.99, 95% confidence interval CI 0.77–1.29), papillary (HRQ4 vs. Q1 = 1.06, 95% CI 0.80–1.41) or follicular TC (HRQ4 vs. Q1 = 1.10, 95% CI 0.55–2.22) were found. No associations were observed either for flavonoids, phenolic acids or the rest of classes and subclasses of polyphenols. After stratification by body mass index (BMI), an inverse association between the intake of polyphenols (p‐trend = 0.019) and phenolic acids (p‐trend = 0.007) and differentiated TC risk in subjects with BMI ≥ 25 was observed. In conclusion, our study showed no associations between dietary polyphenol intake and differentiated TC risk; although further studies are warranted to investigate the potential protective associations in overweight and obese individuals.
What's new?
Polyphenols are secondary plant metabolites with health protective properties but whether a diet rich in polyphenols protects from thyroid cancer has not been conclusively explored. In this large prospective study, no associations were observed between dietary polyphenol intake and differentiated thyroid cancer risk. The authors recommend further studies to investigate potential associations specifically in overweight and obese individuals.
Background/Objectives
Polyphenols are plant secondary metabolites with a large variability in their chemical structure and dietary occurrence that have been associated with some protective effects ...against several chronic diseases. To date, limited data exist on intake of polyphenols in populations. The current cross-sectional analysis aimed at estimating dietary intakes of all currently known individual polyphenols and total intake per class and subclass, and to identify their main food sources in the European Prospective Investigation into Cancer and Nutrition cohort.
Methods
Dietary data at baseline were collected using a standardized 24-h dietary recall software administered to 36,037 adult subjects. Dietary data were linked with Phenol-Explorer, a database with data on 502 individual polyphenols in 452 foods and data on polyphenol losses due to cooking and food processing.
Results
Mean total polyphenol intake was the highest in Aarhus—Denmark (1786 mg/day in men and 1626 mg/day in women) and the lowest in Greece (744 mg/day in men and 584 mg/day in women). When dividing the subjects into three regions, the highest intake of total polyphenols was observed in the UK health-conscious group, followed by non-Mediterranean (non-MED) and MED countries. The main polyphenol contributors were phenolic acids (52.5–56.9 %), except in men from MED countries and in the UK health-conscious group where they were flavonoids (49.1–61.7 %). Coffee, tea, and fruits were the most important food sources of total polyphenols. A total of 437 different individual polyphenols were consumed, including 94 consumed at a level >1 mg/day. The most abundant ones were the caffeoylquinic acids and the proanthocyanidin oligomers and polymers.
Conclusion
This study describes the large number of dietary individual polyphenols consumed and the high variability of their intakes between European populations, particularly between MED and non-MED countries.
Specific nutrients or foods have been inconsistently associated with ulcerative colitis (UC) or Crohn's disease (CD) risks. Thus, we investigated associations between diet as a whole, as dietary ...patterns, and UC and CD risks.
Within the prospective EPIC (European Prospective Investigation into Cancer) study, we set up a nested matched case-control study among 366,351 participants with inflammatory bowel disease data, including 256 incident cases of UC and 117 of CD, and 4 matched controls per case. Dietary intake was recorded at baseline from validated food frequency questionnaires. Incidence rate ratios of developing UC and CD were calculated for quintiles of the Mediterranean diet score and a posteriori dietary patterns produced by factor analysis.
No dietary pattern was associated with either UC or CD risks. However, when excluding cases occurring within the first 2 years after dietary assessment, there was a positive association between a "high sugar and soft drinks" pattern and UC risk (incidence rate ratios for the fifth versus first quintile, 1.68 1.00-2.82; Ptrend = 0.02). When considering the foods most associated with the pattern, high consumers of sugar and soft drinks were at higher UC risk only if they had low vegetables intakes.
A diet imbalance with high consumption of sugar and soft drinks and low consumption of vegetables was associated with UC risk. Further studies are needed to investigate whether microbiota alterations or other mechanisms mediate this association.
Telomere deregulation is a hallmark of cancer. Telomere length measured in lymphocytes (LTL) has been shown to be a risk marker for several cancers. For pancreatic ductal adenocarcinoma (PDAC) ...consensus is lacking whether risk is associated with long or short telomeres. Mendelian randomization approaches have shown that a score built from SNPs associated with LTL could be used as a robust risk marker. We explored this approach in a large scale study within the PANcreatic Disease ReseArch (PANDoRA) consortium. We analyzed 10 SNPs (ZNF676‐rs409627, TERT‐rs2736100, CTC1‐rs3027234, DHX35‐rs6028466, PXK‐rs6772228, NAF1‐rs7675998, ZNF208‐rs8105767, OBFC1‐rs9420907, ACYP2‐rs11125529 and TERC‐rs10936599) alone and combined in a LTL genetic score (“teloscore”, which explains 2.2% of the telomere variability) in relation to PDAC risk in 2,374 cases and 4,326 controls. We identified several associations with PDAC risk, among which the strongest were with the TERT‐rs2736100 SNP (OR = 1.54; 95%CI 1.35–1.76; p = 1.54 × 10−10) and a novel one with the NAF1‐rs7675998 SNP (OR = 0.80; 95%CI 0.73–0.88; p = 1.87 × 10−6, ptrend = 3.27 × 10−7). The association of short LTL, measured by the teloscore, with PDAC risk reached genome‐wide significance (p = 2.98 × 10−9 for highest vs. lowest quintile; p = 1.82 × 10−10 as a continuous variable). In conclusion, we present a novel genome‐wide candidate SNP for PDAC risk (TERT‐rs2736100), a completely new signal (NAF1‐rs7675998) approaching genome‐wide significance and we report a strong association between the teloscore and risk of pancreatic cancer, suggesting that telomeres are a potential risk factor for pancreatic cancer.
What's new?
How does lymphocyte telomere length affect pancreatic cancer risk? These authors analyzed 10 SNPs associated with telomere length and their relationship with pancreatic cancer risk, using data from the Pancreatic Disease Research (PANDoRA) consortium. Each patient received a “teloscore” based on the combined SNP data, and it turned out that a low teloscore ‐ predicting a short telomere ‐ was associated with increased pancreatic cancer risk. The researchers also identified for the first time a significant genome‐wide association between a SNP, TERT‐rs2736100, and increased pancreatic cancer risk. They also discovered a completely novel association between a SNP, NAF1‐rs7675998, and decreased risk.
Recently, we identified unique processing patterns of apolipoprotein A2 (ApoA2) in patients with pancreatic cancer. Our study provides a first prospective evaluation of an ApoA2 isoform ...(“ApoA2‐ATQ/AT”), alone and in combination with carbohydrate antigen 19–9 (CA19‐9), as an early detection biomarker for pancreatic cancer. We performed ELISA measurements of CA19‐9 and ApoA2‐ATQ/AT in 156 patients with pancreatic cancer and 217 matched controls within the European EPIC cohort, using plasma samples collected up to 60 months prior to diagnosis. The detection discrimination statistics were calculated for risk scores by strata of lag‐time. For CA19‐9, in univariate marker analyses, C‐statistics to distinguish future pancreatic cancer patients from cancer‐free individuals were 0.80 for plasma taken ≤6 months before diagnosis, and 0.71 for >6–18 months; for ApoA2‐ATQ/AT, C‐statistics were 0.62, and 0.65, respectively. Joint models based on ApoA2‐ATQ/AT plus CA19‐9 significantly improved discrimination within >6–18 months (C = 0.74 vs. 0.71 for CA19‐9 alone, p = 0.022) and ≤ 18 months (C = 0.75 vs. 0.74, p = 0.022). At 98% specificity, and for lag times of ≤6, >6–18 or ≤ 18 months, sensitivities were 57%, 36% and 43% for CA19‐9 combined with ApoA2‐ATQ/AT, respectively, vs. 50%, 29% and 36% for CA19‐9 alone. Compared to CA19‐9 alone, the combination of CA19‐9 and ApoA2‐ATQ/AT may improve detection of pancreatic cancer up to 18 months prior to diagnosis under usual care, and may provide a useful first measure for pancreatic cancer detection prior to imaging.
What's new?
A new biomarker may boost sensitivity of early pancreatic cancer testing. Because the disease is rare, and most cases arise sporadically, screening focused on patients with a family history is inadequate, but general‐population screening remains impractical. Here, the authors investigated a newly identified biomarker for pancreatic cancer, an isoform of apolipoprotein A2 called ApoA2‐ATQ/AT. They tested pre‐diagnosis blood samples collected from the EPIC cohort and looked at ApoA2‐ATQ/AT in combination with the commonly used biomarker, CA19‐9. Using both markers together enabled earlier detection of cancer than CA19‐9 alone, up to 18 months before diagnosis.
A total of 308,036 women were selected from the European Prospective Investigation into Cancer and Nutrition (EPIC) study to evaluate the association between tobacco smoking and the risk of cervical ...intraepithelial neoplasia of grade 3 (CIN3)/carcinoma in situ (CIS) and invasive cervical cancer (ICC). At baseline, participants completed a questionnaire and provided blood samples. During a mean follow‐up time of 9 years, 261 ICC cases and 804 CIN3/CIS cases were reported. In a nested case–control study, the baseline sera from 609 cases and 1,218 matched controls were tested for L1 antibodies against HPV types 11, 16, 18, 31, 33, 35, 45, 52, 58, and antibodies against Chlamydia trachomatis (CT), and Human Herpes Virus 2 (HHV‐2). Cervical samples were not available for HPV‐DNA analysis in this study. Multivariate analyses were used to estimate associations between smoking and risk of CIN3/CIS and ICC in the cohort and the case–control studies. In the cohort analyses smoking status, duration and intensity showed a two‐fold increased risk of CIN3/CIS and ICC, while time since quitting was associated with a two‐fold reduced risk. In the nested case–control study, consistent associations were observed after adjustment for HPV, CT and HHV‐2 serostatus, in both HPV seronegative and seropositive women. Results from this large prospective study confirm the role of tobacco smoking as an important risk factor for both CIN3/CIS and ICC, even after taking into account HPV exposure as determined by HPV serology. The strong beneficial effect of quitting smoking is an important finding that will further support public health policies for smoking cessation.
What's new?
Tobacco smoking is a cited cause of cervical cancer, but whether it causes cervical malignancy independent of human papillomavirus (HPV) infection is unclear. Here, strong associations were found between most measures of tobacco smoking and the risk of cervical intraepithelial neoplasia of grade 3/carcinoma in situ and invasive cervical cancer, after taking into account past exposure to HPV infection. Quitting smoking was associated with a 2‐fold risk reduction. The findings confirm the role of tobacco smoking in cervical carcinogenesis and show that quitting the habit has important benefits for cancer protection.
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