Hospital-based Case-control Studies Research Articles

Fiber-type prebiotics and gynecological and breast cancers risk: the PrebiotiCa study.

Prebiotics may influence the risk of hormone-related female cancers by modulating the gut microbiota involved in estrogens metabolism. We evaluated the association of fiber-type prebiotic intake with breast, endometrial, and ovarian cancers. Data derived from a network of Italian hospital-based case-control studies (1991-2006), including 2560 cases of cancer of the breast (2588 controls), 454 of the endometrium (908 controls) and 1031 of the ovary (2411 controls). Inulin-type fructans (ITFs), and selected fructo-oligosaccharides (FOSs, nystose, kestose and 1F-β-fructofuranosylnystose) and galacto-oligosaccharides (GOSs, raffinose and stachyose) were quantified in food products. Prebiotic intake was estimated by multiplying food frequency questionnaire intake by the foods' prebiotic content. Odds ratios (OR) and the corresponding 95% confidence intervals (CI) were derived by multiple logistic regression models. Nystose intake was marginally directly associated with breast (OR for the 4th versus the 1st quartile 1.20, 95% CI: 1.00-1.45), ovarian (OR 1.39, 95% CI: 1.04-1.84) and endometrial cancer risk (OR 1.32, 95% CI: 0.85-2.03). High 1F-β-fructofuranosylnystose intake was inversely associated with ovarian cancer (OR 0.67, 95% CI: 0.52-0.85). ITFs, kestose, raffinose and stachyose were not associated with the three cancers. The intake of most fiber-type prebiotics was not appreciably and consistently associated with breast, endometrial and ovarian cancer risks.

The association between dietary fiber intake and gastric cancer: a pooled analysis of 11 case-control studies.

Gastric cancer (GC) is among the leading causes of cancer mortality worldwide. The objective of this study was to investigate the association between dietary fiber intake and GC. We pooled data from 11 population or hospital-based case-control studies included in the Stomach Cancer Pooling (StoP) Project, for a total of 4865 histologically confirmed cases and 10,626 controls. Intake of dietary fibers and other dietary factors was collected using food frequency questionnaires. We calculated the odds ratios (OR) and 95% confidence intervals (CI) of the association between dietary fiber intake and GC by using a multivariable logistic regression model adjusted for study site, sex, age, caloric intake, smoking, fruit and vegetable intake, and socioeconomic status. We conducted stratified analyses by these factors, as well as GC anatomical site and histological type. The OR of GC for an increase of one quartile of fiber intake was 0.91 (95% CI: 0.85, 0.97), that for the highest compared to the lowest quartile of dietary fiber intake was 0.72 (95% CI: 0.59, 0.88). Results were similar irrespective of anatomical site and histological type. Our analysis supports the hypothesis that dietary fiber intake may exert a protective effect on GC.

A novel approach to assess diet diversity: a development of the Nutritional Functional Diversity indicator.

Diversity is a key element of diet quality. The Food Variety Score (FVS) is used to assess diversity, especially in low- and middle-income countries. It sums up the number of foods consumed ignoring their nutrient content. A more suitable index should combine the number of foods consumed and their nutritional composition. We adapted the Nutritional Functional Diversity indicator (NFD), proposed by ecologists, to measure diversity in the human diet. We compared NFD and FVS evaluating subjects' distributions across quartiles of the two diversity indices. To evaluate which one reflected a higher diet quality, we estimated associations between these two diversity indices and diet quality measures, i.e., the Mediterranean Diet Score (MDS) and the Healthy Eating Index-2015 (HEI-2015). Associations were expressed by odds ratios (OR) and corresponding 95% confidence intervals (CI). We used the data of controls only derived from an integrated series of hospital-based case-control cancer studies conducted in different Italian areas. The NFD identifies groups of foods based on a set of nutrients according to a cluster analysis. Some steps are required: creating a food-nutrient matrix; clustering of the Euclidean food-food distance matrix to identify groups of foods with nutritional (dis)similarities; and calculating the NFD as the ratio between the sum of branch lengths of the dendrogram belonging to the number of foods consumed by individuals (i.e., subject-specific diversity) and the sum of all branch lengths of the dendrogram (i.e., maximal diversity). More than one quarter of individuals (28.4%) were differently classified within quartiles of the two diversity indices. For both indices, increasing the diversity level increased the risk for adhering to MDS (OR for NFD = 11.26; 95% CI: 7.88-16.09, and OR for FVS = 6.80; 95% CI: 4.84-9.54) and to HEI-2015 (OR for NDF = 2.86; 95% CI: 2.39-3.42, and OR for FVS = 2.72; 95% CI: 2.27-3.26). Associations were stronger for NFD. Our findings showed a greater ability of NFD to assess diet quality quantifying the degree of diversity.

Association of gallstone disease with risk of colorectal cancer: a systematic review and meta-analysis of observational studies.

Numerous studies have assessed the association of gallstones or cholecystectomy (CE) with risk of colorectal cancer (CRC). However, the findings are mixed. To systematically review and meta-analyse the association between the presence of gallstone disease (GD), or CE and the incidence of CRC. Secondary endpoints were the risk based on type of exposure, study design, tumour subsites and sex. PubMed and EMBASE were searched from September 2020 to May 2021. The protocol was registered on the Open Science Foundation Platform. We identified and classified studies according to their design into prospective cohort, population-based case-control, hospital-based case-control and necropsy studies reporting CRC incidence among individuals with diagnosed GD or after CE (or both). Among 2157 retrieved studies, 65 (3%) met the inclusion criteria. We followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. Data were extracted by two independent reviewers. We evaluated the quality of the study according to the Newcastle-Ottawa Scale and only studies with a score of 6 and above were included in the final analyses. We pooled log-transformed odds ratios/risk ratios from the available adjusted models to estimate a summary relative risk (RR) and 95% confidence interval (CI) in a random-effects model. The primary outcome was overall CRC incidence. We also conducted secondary analyses according to sex and CRC subsites (proximal colon, distal colon and rectum). The outcome was measured by RRs with 95% CIs. The overall association of GD and/or CE with CRC was RR = 1.15 (1.08; 1.24), primarily driven by hospital-based case-control studies [RR = 1.61 (1.29; 2.01)], whereas a more modest association was found in population-based case-control and cohort studies [RR = 1.10 (1.02; 1.19)]. Most hospital-based case-control and necropsy studies reported estimates that were adjusted for age and sex only, leaving room for residual confounding; therefore we restricted to population-based case-control and cohort studies for our subsequent analyses. Similar associations were found for women [RR = 1.21 (1.05; 1.4) and men (RR = 1.24 (1.06; 1.44)]. When assessed by CRC subsites, GD and CE were primarily associated with higher risk of proximal colon cancer [RR = 1.16 (1.07; 1.26)] but not distal colon cancer [RR = 0.99 (0.96; 1.03)] or rectal cancer [RR = 0.94 (0.89; 1.00)]. Gallstones are associated with a modestly increased risk of colon cancer, primarily in the proximal colon.

Altered Levels of Blood Glucose and Serum Lipids in Sudanese Patients with Ovarian Cancer

Background: The etiology of ovarian cancer is not well-understood; numerous metabolomics profiling, epidemiological, and hospital-based case control studies have associated abnormal levels of blood glucose and serum lipids with the risk and the prognosis of various types of cancers including ovarian cancer. The association between the risk of the incidence of ovarian cancer and the alterations in the levels of blood glucose and serum lipids is not well defined. Objective: In this study we aimed to compare the levels of blood glucose, triacylglycerols, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol in patients with different stages of ovarian cancer and healthy controls to determine how they relate to the risk and prognosis of ovarian cancer. Methodology: In a case-control cross sectional study, we enrolled ninety-nine Sudanese women, diagnosed with ovarian cancer but had not received any kind of treatment as the study group, and a control group of forty-one age-matched, apparently healthy women. The patients were classified according to the International Federation of Obstetricians and Gynecologists staging system into two groups: early stages (stage I & II) and late stages (stages III & IV). Blood glucose and serum lipids; triacylglycerols, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol were determined by enzymatic colorimetric methods using commercially available analytical kits. The IBM SPSS version 20 software was used for statistical analysis. A Mann-Whitney U test was used for comparison of the median concentrations of blood glucose, triacylglycerols, total cholesterol, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol in the study groups. Logistic regression model was used to estimate the relative risk of ovarian cancer in relation to levels of blood glucose and serum lipids. P value of 0.05 was considered significant. Results: Our data indicated significantly higher levels of blood glucose (p , triacylglycerols (p = 0.002), and low-density lipoprotein cholesterol (p , and lower levels of high-density lipoprotein cholesterol (p = 0.023), in ovarian cancer patients compared to the control subjects. No significant difference was found in the levels of blood glucose or any of the serum lipids between patients in the early stages (stage I & II) and those in late stages (stage III & IV) of ovarian cancer. The logistic regression analysis indicated significant association between the elevated levels of the blood glucose, triacylglycerols and low-density lipoprotein cholesterol and the risk of the ovarian cancer. Conclusion: We conclude that the levels of blood glucose, triacylglycerols, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol differ significantly between ovarian cancer patients and the healthy control subjects. The risk of ovarian cancer was positively associated with the levels of blood glucose, triacylglycerols and low-density lipoprotein cholesterol, and negatively associated with levels of high-density lipoprotein cholesterol. Therefore, determination of blood glucose and serum lipids, particularly, triacylglycerols, low-density lipoprotein cholesterol may be helpful as diagnostic indicators of ovarian cancer (OC).

Canned Fish Consumption and Upper Digestive Tract Cancers

Canned fish is a widely consumed and affordable food whose effect on cancer risk has been little investigated. We studied its effect on risk of upper digestive tract cancers using data from a network of hospital-based case-control studies from Northern Italy providing information about canned fish consumption as a separate item and including a total of 946 patients with oral cavity and pharynx cancer, 304 patients with esophageal cancer, 230 patients with gastric cancer and 3273 controls. Twenty-three percent of patients with cancer of the oral cavity or pharynx and 26% of those with cancer of the stomach consumed ≥1 serving per week of canned fish, compared to 40% and 49% of the respective control group. Among cases of esophageal cancer and controls 22% consumed ≥1 serving per week of canned fish. Odds ratios for ≥1 vs <1 portion per week were 0.79 (95% Confidence Interval, CI: 0.64–0.97) for cancer of the oral cavity and pharynx, and 0.59 (95% CI: 0.41–0.86) for stomach cancer, whereas there was no inverse association with esophageal cancer. These findings suggest a favorable role of canned fish for selected upper digestive tract cancers.

Epidemiological Review: Esophagus Squamous Cell Carcinoma in India

AbstractWorldwide the incidence of esophagus squamous cell carcinoma (ESCC), remains one of the most common causes of cancer death. ESCC is one of the leading types of cancer in the North and Northeast regions of India among both genders. Risk factors of ESCC include tobacco, alcohol, areca nut, hot beverages, low fruit diet, poor oral hygiene, unpiped water, and human papillomavirus infection. This review tries to elaborate on various modifiable risk factors for ESCC, which have been studied worldwide and need to be studied in India. PubMed was used as a search platform using keywords, such as “esophagus cancer,” “esophagus squamous cell carcinoma,” “epidemiology,” “India,” “incidence,” “mortality,” “risk factors,” “treatment,” “survival,” “prevention” and their corresponding Medical Subject Heading terms, were used in combination with Boolean operators “OR” and “AND.” Studies from India are mostly hospital-based case-control studies from the North region. Further research is required in India to understand the etiology, to design large-scale screening and prevention strategies.

Spirometric Indices of Charcoal Smoke Exposed Food Grillers in Yenagoa South-South, Nigeria

Background: Pulmonary function is an important marker of the effects of air pollution on the exposed population. Mild to moderate reductions of FEV1/FVC, FEV1, FEV1%, PEF, and FEF25–75 have been associated with the exposure to biomass burning in cross-sectional studies. Some hospital-based case-control studies, confirm that people exposed to biomass smoke have high risk for developing airflow obstruction with significant reduction of FEV1 and FEV1/FVC. However, none of these studies has evaluated lung function parameters among charcoal smoke exposed food grillers. Therefore this index study took a look at spirometric indices among food grillers exposed to charcoal smoke in Yenagoa, South-South Nigeria. Methods: This was a comparative observational cross-sectional study of charcoal smoke exposed spirometric indices of food grillers compared to fruit sellers The Medical Research Council (MRC) Questionnaire was administered to participants and a “one-on-one” interview was conducted by the researcher using the questionnaires.Information obtained included socio-demographic characteristics such as age, gender, marital status and level of education. Spirometry was performed in accordance with the ATS/ERS using standard single reusable turbine spirometer (MIR Spirobank II Basic; manufactured by P &amp; A Medical Limited). Spirograms that met the ATS/ERS criteria for acceptability were used. Information obtained with the spirometer were FEV1, FVC, FEV1/FVC, PEF and FEF25-75. A portable HANA analogue weight machine was used to weigh the study participants and a flexible plastic tape measure was used to measure the heights of participants Results: A total of one hundred and sixty (160) participants made up of eighty (80) food-grillers and fruit-sellers (controls) respectively were recruited for this study. A normal lung function pattern was found in 60 (75.0%) of food-grillers and 72 (90.0%) of controls. This shows that more fruit-sellers had normal lung function pattern, and this was statistically significant (p = 0.013). Obstructive pattern was found in 16 (20.0%) of food-grillers and 6 (7.5%) of controls (p = 0.022). The mean lung function values for food-grillers compared to fruit sellers were: FEV1=2.8±0.5L vs 3.2±0.5 (72.3±5.8% predicted); FVC=3.6±0.6L vs 3.9±0.8 (76.8±6.6% predicted), FEV1/FVC=78.5±4.9 vs 85.3 ±5.3 (77.1±5.4% predicted); PEF=5.7± 1.2L/s vs 6.9 ±2.9 (81.6±7.3% predicted) and FEF25-75=2.8±0.8L/s vs 3.0 (±0.4) (80.5±15.3% predicted). The values were statistically different between food-grillers and controls (p &lt; 0.001). Conclusion: Exposure to charcoal smoke is associated with the development of lung function abnormalities and reduction in lung function parameters. Increasing exposure time to charcoal smoke increase the likelihood of lung function abnormalities.

An overview of systematic evidence on oral microbial composition for orodigestive tract cancer risk

We summarized published systematic reviews of studies evaluating oral microbial composition for orodigestive cancer risk. A PubMed literature search was conducted for the most recent time period between January 1, 2019 and April 25, 2022, for systematic reviews in English language using keywords and MeSH terms in combination. Seven systematic reviews included all published observational studies until June 2021 with 8–34 individual studies evaluated in each of those reviews. The individual studies were primarily hospital-based case–control studies with only six population-based evaluations (five prospective; one case control). The oral cavity, oro-and hypopharynx, esophagus, stomach, colorectum, liver, and pancreas were the cancer sites investigated. Saliva, oral rinse, subgingival and dental plaque, surface tissue swabs, biopsy tissue specimens, and tongue-coating samples were analyzed for oral microbial composition using next-generation sequencing techniques primarily 16S rRNA sequencing. The total sample size in different reviews ranged between 578 and 2769 cases and 261 and 3519 controls with small individual studies (3–250 cases and 2–465 controls). To date, there were four hospital-based case–control studies from India. The overall findings were restricted to bacterial communities. Compared to controls, the alpha-and beta-diversity for these cancer sites either showed no difference or inconsistent patterns. A few noteworthy differential abundances at the genus level for selected cancer sites included oral cavity – increased Fusobacterium, Parvimonas, and Peptostreptococcus and decreased Streptococcus, colorectum – increased Fusobacterium, Gemella, Peptostreptococcus, Prevotella, and Lautropia, pancreas – increased Porphyromonas and Alloprevotella, and esophagus – increased Tannerella. For clinical and public health translation, the identified leads might require validations in prospective population-based studies with rigorous methods, species-level characterizations, and functional analysis to prove causal associations.

Genome-wide association study reveals novel loci for adult type 1 diabetes in a 5-year nested case-control study.

BACKGROUNDType 1 diabetes (T1D) is a severe and prevalent metabolic disease. Due to its high heredity, an increasing number of genome-wide association studies have been performed, most of which were from hospital-based case-control studies with a relatively small sample size. The association of single nucleotide polymorphisms (SNPs) and T1D has been less studied and is less understood in natural cohorts.AIMTo investigate the significant variants of T1D, which could be potential biomarkers for T1D prediction or even therapy.METHODSA genome-wide association study (GWAS) of adult T1D was performed in a nested case-control study (785 cases vs 804 controls) from a larger 5-year cohort study in Suzhou, China. Potential harmful or protective SNPs were evaluated for T1D. Subsequent expression and splicing quantitative trait loci (eQTL and sQTL) analyses were carried out to identify target genes modulated by these SNPs.RESULTSA harmful SNP for T1D, rs3117017 [odds ratio (OR) = 3.202, 95% confidence interval (CI): 2.296-4.466, P = 9.33 × 10-4] and three protective SNPs rs55846421 (0.113, 0.081-0.156, 1.76 × 10-9), rs75836320 (0.283, 0.205-0.392, 1.07 × 10-4), rs362071 (0.568, 0.495-0.651, 1.66 × 10-4) were identified. Twenty-two genes were further identified as potential candidates for T1D onset. CONCLUSIONWe identified a potential genetic basis of T1D, both protective and harmful, using a GWAS in a larger nested case-control study of a Chinese population.

Well-Water Consumption and Risk of Parkinson's Disease: A Meta-Analysis of 15 Observational Studies.

IntroductionThe relationship between the risk of Parkinson disease and well-water consumption has been extensively studied, but the results have been contradictory. Therefore, we conducted a meta-analysis of observational studies to systematically assess the relationship between well-water consumption and Parkinson disease risk.MethodsWe followed the PRISMA checklist in completing the meta-analysis. We searched two electronic databases (PubMed, EBSCO, EMBASE and Cochrane) from establishment to October, 2021, to identify relevant studies linking well-water drinking to Parkinson risk. We used a random-effects model to calculate the overall odds ratio (OR) with 95% confidence interval (CI). To reduce intragroup heterogeneity, we conducted subgroup analyses according to the research design and geographic area.ResultsAfter careful review, a total of 15 case–control-designed studies included data suitable for our meta-analysis. The total number of cases and total controls that contribute to the combined OR were 2182 and 2456. The combined OR for ever well-water drinkers versus non-drinkers was 1.16 (95% CI: 0.97–1.39, I2 = 44.52%). In subgroup analysis by geographic area, a significant association was observed in studies conducted in Asia (OR 1.29, 95% CI: 1.05–1.58, I2 = 0.0%, p for heterogeneity = 0.460) but not in studies conducted in America (OR 0.97, 95% CI: 0.76–1.24, I2 = 41.2%, p for heterogeneity = 0.164). In subgroup analysis by study design, a borderline significant association emerged in hospital-based case–control studies (OR 1.31, 95% CI: 1.04–1.65, I2 = 40.9%, p for heterogeneity = 0.118) but not in population-based case–control studies (OR 0.96, 95% CI: 0.73–1.26, I2 = 41.1%, p for heterogeneity = 0.165).DiscussionOur results indicate that there is no significant correlation between well-water consumption and PD risk.

A Likely Role for a Novel Cell Therapeutic Target of Transforming Growth Factor-β1 on Radiation Pneumonitis in Lung and Nasopharyngeal Cancer Patients

The association between the polymorphism of transforming growth factor (TGF)-β1 and risk of radiation pneumonitis has been extensively investigated; however, conclusive results were unavailable. Eligible studies were identified from the database of Medline, Web of Science, EMBASE, and CNKI (China Knowledge Resource Integrated Database) up to September 2019. The odds ratio (OR) and 95% confidence interval (95% CI) were used to assess the strength of the relationship. The results showed that there were associations between TGF 869 T/C (rs1982073) and risks of radiation pneumonitis. Subgroup analyses showed that TGF 869 T/C was associated with risk of radiation pneumonitis in Caucasians (OR [95% CI]: 0.45 [0.31 to 0.67] for C carriers vs. TT). In addition, subgroup analyses also suggested that the C allele was associated with decreased risks of radiation pneumonitis among hospital-based case–control studies (0.56 [0.39 to 0.82] for C carriers vs. TT). Meanwhile, C allele was also suggested to be associated with decreased risk of radiation pneumonitis among PCC (0.60 [0.38 to 0.96] for C carriers vs. TT). Especially, C allele was also found to be associated with decreased risk of radiation pneumonitis from the participants with lung cancer (0.57 [0.37 to 0.90] for C carriers vs. TT). Our meta-analysis shows that T allele in TGF 869 T/C is significantly associated with the increased risk of radiation pneumonitis, especially for Caucasians, and for the participants with lung cancer.

Obstructive Sleep Apnea and Keratoconus: A Systematic Review and Meta-analysis.

Despite the increasing number of studies focused on the association between obstructive sleep apnea (OSA) and keratoconus (KC), to date, no comprehensive meta-analysis or systematic review was published. The objective of this study was to evaluate the association between OSA and KC. Sources of data were PubMed, Scopus, and Web of Science databases. The criteria for study eligibility were case-control studies and cohort studies reporting data on the association of OSA with KC with risk ratio, odds ratio, or hazard ratio with 95% confidence intervals or sufficient raw data for calculation. Meta-analysis was conducted with a random-effects model using odds ratio with 95% confidence interval as the effect size. Heterogeneity was evaluated using the Q and I tests. Sensitivity analysis and assessment of publication bias were performed. Five studies (four case-control studies and one cohort study) published between 2012 and 2016 and involving 33,844 subjects (16,922 patients with KC, 16,922 controls) were included in this meta-analysis. A significant association between OSA and KC has been shown (pooled odds ratio, 1.841; 95% confidence interval, 1.163 to 2.914; P = .009). A significant heterogeneity was observed (Q = 15.8, I = 74.6%). There was no evidence of significant publication bias (P = .07). The sensitivity analyses indicated the stability of results. Heterogeneity across the studies was observed. Data from four hospital-based case-control studies and one large population-based cohort study were combined. Most of the included studies ascertained OSA by the Berlin Questionnaire, which is a screening tool. This meta-analysis provides significant evidence that OSA is associated with KC. Therefore, a proper screening for OSA is warned for KC patients for the prevention of various cardiovascular comorbidities. Further prospective studies are warranted to explore more in-depth the casual relationship between the two conditions.

Design choices for observational studies of the effect of exposure on disease incidence

The purpose of this paper is to help readers choose an appropriate observational study design for measuring an association between an exposure and disease incidence. We discuss cohort studies, sub-samples...

Egg Consumption and Risk of Upper Aero-Digestive Tract Cancers: A Systematic Review and Meta-Analysis of Observational Studies

Limited data are available that summarize the relation between egg intake and the risk of upper aero-digestive tract (UADT) cancers. This systematic review and meta-analysis was conducted to investigate the association between egg intake and the risk of UADT cancers. Medline/PubMed, ISI web of knowledge, EMBASE, Scopus, and Google Scholar were searched using relevant keywords. Observational studies conducted on humans investigating the association between egg consumption and the risk of UADT cancers were included. Overall, 38 studies with a total of 164,241 subjects (27, 025 cases) were included. Based on 40 effect sizes from 32 case-control studies, we found a 42% increased risk of UADT cancers among those with the highest egg consumption (ranging from ≥1 meal/d to ≥1 time/mo among studies) compared to those with the lowest intake (ranging from 0-20g/d to never consumed among studies) (overall OR: 1.42; 95% CI: 1.19, 1.68; P<0.001). However, this association was only evident in hospital-based case-control (HCC) studies (OR=1.50; 95% CI: 1.34, 1.68; P<0.001 for 'oropharyngeal and laryngeal cancer' and OR: 1.27; 95% CI: 1.08, 1.50; P=0.004 for esophageal cancer) and not in population-based case-control (PCC) studies (OR=1.25; 95% CI: 0.59, 2.67; P=0.56 for 'oropharyngeal and laryngeal cancer' and OR: 1.29; 95% CI: 0.92, 1.81; P=0.13 for esophageal cancer). In addition, the association was not significant in prospective cohort studies (overall OR: 0.86; 95% CI: 0.71, 1.04; P=0.11). Considering individual cancers, a positive association was observed between the highest egg consumption, compared with the lowest, and risk of oropharyngeal (OR: 1.88; 95% CI: 1.61, 2.20; P<0.001), laryngeal (OR: 1.83; 95% CI: 1.45, 2.32; P<0.001), oral & pharyngeal & laryngeal (OR: 1.37; 95% CI: 1.12, 1.67; P<0.001), and esophageal cancers (OR: 1.28; 95% CI: 1.10,1.48; P=0.001). We also found an inverse association between egg intake and the risk of oral cancer (OR: 0.78; 95% CI: 0.62, 0.99; P=0.04). In conclusion, high egg consumption (ranging from ≥1 meal/d to ≥1 time/mo among studies) was associated with increased risk of UADT cancers only in HCC studies but not in PCC or prospective cohort studies. PROSPERO registration number: CRD42018102619.

Challenges in assessing the sunscreen-melanoma association.

Whether sunscreen use affects melanoma risk has been widely studied with contradictory results. To answer this question we performed a systematic review of all published studies, accounting for sources of heterogeneity and bias. We searched for original articles investigating the sunscreen‐melanoma association in humans to February 28, 2018. We then used random‐effects meta‐analysis to combine estimates of the association, stratified by study design. Stratified meta‐analysis and meta‐regression were used to identify sources of heterogeneity. We included 21,069 melanoma cases from 28 studies published 1979–2018: 23 case–control (11 hospital‐based, 12 population‐based), 1 ecological, 3 cohort and 1 randomised controlled trial (RCT). There was marked heterogeneity across study designs and among case–control studies but adjustment for confounding by sun exposure, sunburns and phenotype systematically moved estimates toward decreased melanoma risk among sunscreen users. Ever‐ vs. never‐use of sunscreen was inversely associated with melanoma in hospital‐based case–control studies (adjusted odds ratio (OR) = 0.57, 95%confidence interval (CI) 0.37–0.87, p heterogeneity < 0.001), the ecological study (rate ratio = 0.48, 95%CI 0.35–0.66), and the RCT (hazard ratio (HR) = 0.49, 95%CI 0.24–1.01). It was not associated in population‐based case–control studies (OR = 1.17, 95%CI 0.90–1.51, p heterogeneity < 0.001) and was positively associated in the cohort studies (HR = 1.27, 95%CI 1.07–1.51, p heterogeneity = 0.236). The association differed by latitude (p interaction = 0.042), region (p interaction = 0.008), adjustment for naevi/freckling (p interaction = 0.035), and proportion of never‐sunscreen‐users (p interaction = 0·012). Evidence from observational studies on sunscreen use and melanoma risk was weak and heterogeneous, consistent with the challenges of controlling for innate confounding by indication. The only RCT showed a protective effect of sunscreen.

Association Between Organic Dust Exposure and Adult-Asthma: A Systematic Review and Meta-Analysis of Case-Control Studies.

BackgroundExposure to organic dust has been widely investigated as a potential risk factor for asthma with different results. To clarify a potential relationship, we performed the present meta-analysis to integrate the results of studies examining the association of organic dust exposure with asthma.MethodsA comprehensive literature search in the electronic databases including EMBASE, PubMed and Cochrane Library databases (up to August 2018) was conducted. The adjusted odds ratios (ORs) with corresponding 95% confidence interval (CI) for organic dust exposure and asthma were retrieved and pooled to generate summary effect estimates in Revman 5.2.ResultsDatabase searches retrieved 1,016 records. A total of 17 studies containing 3,619 cases and 6,585 controls were finally included in our meta-analysis. The summary estimates suggested that organic dust exposure was positively associated with asthma (OR, 1.48; 95% CI, 1.26–1.75; P < 0.00001), whether among population-based case-control studies (OR, 1.24; 95% CI, 1.13–1.35; P < 0.00001) or hospital-based case-control studies (OR, 2.79; 95% CI, 1.27–6.12; P = 0.01). Subgroup analysis showed that paper/wood (OR, 1.62; 95% CI, 1.38–1.90; P < 0.00001), flour/grain (OR, 1.48; 95% CI, 1.11–1.97; P = 0.008), and textile dust (OR, 1.50; 95% CI, 1.08–2.09; P = 0.02) exposure were significantly associated with asthma.ConclusionsBased on the studies evaluated, our meta-analysis results prompt that organic dust exposure is a risk factor inducing asthma, although precise analysis focus on specific organic dust materials is still warranted.

Body Mass Index, Diabetes and Intrahepatic Cholangiocarcinoma Risk: The Liver Cancer Pooling Project and Meta-analysis.

Obesity and diabetes are associated with an increased liver cancer risk. However, most studies have examined all primary liver cancers or hepatocellular carcinoma, with few studies evaluating intrahepatic cholangiocarcinoma (ICC), the second most common type of liver cancer. Thus, we examined the association between obesity and diabetes and ICC risk in a pooled analysis and conducted a systematic review/meta-analysis of the literature. For the pooled analysis, we utilized the Liver Cancer Pooling Project, a consortium of 13 US-based, prospective cohort studies with data from 1,541,143 individuals (ICC cases n = 414). In our systematic review, we identified 14 additional studies. We then conducted a meta-analysis, combining the results from LCPP with results from the 5 prospective studies identified through September 2017. In the LCPP, obesity and diabetes were associated with a 62% [Hazard Ratio (HR) = 1.62, 95% Confidence Interval (CI): 1.24-2.12] and an 81% (HR = 1.81, 95% CI: 1.33-2.46) increased ICC risk, respectively. In the meta-analysis of prospectively ascertained cohorts and nested case-control studies, obesity was associated with a 49% increased ICC risk [Relative Risk (RR) = 1.49, 95% CI: 1.32-1.70; n = 4 studies; I2 = 0%]. Diabetes was associated with a 53% increased ICC risk (RR = 1.53, 95% CI: 1.31-1.78; n = 6 studies). While we noted heterogeneity between studies (I2 = 67%) for diabetes, results were consistent in subgroup analyses. Results from hospital-based case-control studies (n = 9) were mostly consistent, but these studies are potentially subject to reverse causation. These findings suggest that obesity and diabetes are associated with increased ICC risk, highlighting similar etiologies of hepatocellular carcinoma and intrahepatic cholangiocarcinoma. However, additional prospective studies are needed to verify these associations.

Association between serum copper levels and cervical cancer risk: a meta-analysis.

Whether serum copper levels were higher in patients with cervical cancer than that in controls was controversial. Hence, we conducted the present study to explore the relationship between serum copper levels and cervical cancer. We searched PubMed, WanFang, and China National Knowledge Internet (CNKI) for relevant studies before November 30, 2017. Standardized mean difference (SMD) and 95% confidence interval (CI) were used to combine results across studies using the random-effect model. A total of 14 publications involving 747 patients with cervical cancer and 1014 controls were eligible through inclusion criteria. In comparison with controls, serum copper levels were significantly higher in patients with cervical cancer [summary SMD = 1.35; 95%CI: 0.10–2.59], with significant heterogeneity (I2 = 98.8%; P<0.001) was found. Significant association was also found among Asian populations [summary SMD = 1.39; 95%CI: 0.06–2.71]. The association was positive in subgroup analysis of population-based case–control studies (PBCC) [summary SMD = 1.64; 95%CI: 0.02–3.34], but not in hospital-based case–control studies (HBCC). Through a sensitivity analysis, we did not identify any single study to strongly influence the results of our serum copper levels and cervical cancer risk. No publication bias was found in our analysis. In conclusion, our study provided significant evidence of higher serum copper levels in patients with cervical cancer than in controls, suggesting that serum copper exposure was a risk factor on cervical cancer.

Processed Meat and Risk of Renal Cell and Bladder Cancers

ABSTRACTWe assessed the association of processed meat intake with the risk of renal cell carcinoma (RCC) and bladder cancer. We used data from two Italian hospital-based case-control studies, including 1,115 RCC cases and 2,582 controls, and 1,417 bladder cancer cases and 1,732 controls. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) with unconditional logistic regression models, adjusted for major confounders. The median consumption of processed meat in cases and controls was around 2 portions/week (50 g/portion). The ORs for a daily 10 g increment of processed meat was 0.89 (95% CI 0.84–0.94) for RCC and 1.00 (95% CI 0.94–1.06) for bladder cancer. The OR for the highest vs. the lowest consumption was 0.80 (95% CI 0.66–0.96) for RCC and 0.98 (95% CI 0.80–1.21) for bladder cancer. The ORs were consistent in strata of various covariates. For bladder cancer, however, a significant 23% excess risk was found in women (95% CI 1.03–1.47) for a daily increase of 10 g, significantly heterogeneous from the risk recorded in men (OR 0.96, 95% CI 0.90–1.02). The inconsistent results between men and women and the absence of association in both sexes combined indicate that the apparent association between processed meat and bladder cancer in women is unlikely to be causal.