212 research outputs found
Nutrient dietary patterns and the risk of laryngeal cancer : an Italian case-control study
Introduction.
Several studies have indicated a role of diet in the etiology of laryngeal cancer. Since foods and nutrients tend to be closely related and act synergistically, the pecific effect of each dietary component of interest may be difficult to identify and can be partly confounded by other dietary components. Dietary patterns have thus been proposed as a practical tool to describe the association between diet and cancer, given their ability to capture the variations in overall food intake (Newby, Tucker 2004). A few studies have investigated the role of diet on laryngeal cancer through factor analysis.
Aims
We applied exploratory principal component factor analysis (PCFA) to identify a posteriori dietary patterns for a multicentric case-control study conducted in Italy on cancer of the larynx. This a posteriori technique allows to integrate several dietary exposures (i.e. foods, food groups, nutrients) into a smaller number of dietary patterns, that are independent from one another and can be evaluated as risk factors in subsequent analysis for the assessment of cancer risk.
Methods
A case-control study of cancer of the larynx was conducted from 1992 and 2000 in the provinces of Milan and Pordenone, in the Northern Italy. Cases were 460 subjects (415 men, 45 women) admitted to major teaching and general hospitals in the study areas with incident, histologically confirmed squamous cell cancer of the larynx, diagnosed no longer than 1 year before the interview. Controls were 1088 subjects (863 men, 225 women) admitted to the same hospitals for a wide spectrum of acute, non-neoplastic conditions, unrelated to smoking or alcohol drinking, or long term modifications of diet. The subjects\u2019 diet was assessed using a valid and reproducible food frequency questionnaire (FFQ) including 78 foods and beverages, as well as a range of the most common Italian recipes. Subjects were asked to indicate the average weekly consumption for each dietary item; intakes lower than once a month were coded as 0.5 per week. To estimate the intake of various nutrients, an Italian food composition database was used.
We performed an exploratory PCFA on a selected set of 28 major macro- and micro-nutrients. We preliminarily evaluated the correlation matrix to determine if it was factourable, trough visual inspection and statistical procedure (Bartlett\u2019s test of sphericity). Moreover, we evaluated the Kaiser-Meyer-Olkin measure and individual measures of sampling adequacy (Kaiser, 1974). We chose the number of factors to retain based on the following criteria: factor eigenvalue greater than 1, scree plot examination and factor interpretability. We applied a varimax rotation to the factor loadings matrix to achieve a simpler and more interpretable solution. We used nutrients with rotated factor loading greater or equal to 0.63 on a given factor to name the pattern. Factor scores were defined for each subject and for each factor following the weighted least square method. They indicate the degree to which each subject\u2019s diet conforms to one of the identified patterns.
To examine the robustness of the identified dietary patterns, we performed a principal axis factor analysis on the standardized nutrients and a maximum likelihood factor analysis after logarithmic transformation of the original nutrients. We calculated factor scores referring to the multiple regression method and standardizing the results. The correlations between scores referring to the same factor calculated with different methods were equal to 1 for all the comparisons. We also performed factor analysis separately within male and female subsamples and within different centers. All these checks yielded dietary patterns consistent with PCFA the ones obtained on the overall sample.
To assess the reliability and refine the identified factors, we evaluated the internal consistency of those nutrients with a loading greater than 0.40 using standardized Cronbach\u2019s coefficient alpha. We calculated coefficient alphas for each factor and coefficient alphas when item deleted (Cronbach, 1951). To confirm the internal reproducibility of the identified patterns, individuals were randomly placed into one of two equally sized groups, and PCFA was performed separately in both subsamples.
For each factor, we grouped participants into three categories according to quintiles of factor scores among the control population, and estimated the odds ratio and corresponding 95% confidence intervals using unconditional multiple logistic regression models, including all the factors simultaneously. The model was adjusted for sex, age, study center, education, body mass index, physical activity, tobacco smoking, and alcohol drinking.
Results
Five factors were retained according to the defined criteria. These factors explained 79% of the total variance of the original nutrients. The first pattern, named Animal products, had the greatest loadings on calcium, phosphorus, riboflavin, animal protein, saturated fatty acids, zinc, and cholesterol. The second pattern, named Starch-rich, had the greatest loadings on starch, vegetable protein, and sodium. The third pattern, named Vitamins and fiber, had the greatest loadings on vitamin C, total fiber, beta-carotene equivalents, and total folate. The fourth pattern, named Seed oils, had the greatest loadings on linoleic acid, vitamin E, and linolenic acid. The fifth pattern, named Fish-rich, had the greatest loadings on other polyunsaturated fatty acids, and vitamin D.
A direct association was observed between the Animal products pattern and laryngeal cancer (OR=1.94, 95% CI: 1.39-2.70). A borderline direct association was observed between the Starch-rich pattern and laryngeal cancer (OR=1.30, 95% CI: 0.93-1.81). An inverse relationship was observed between the Vitamins and fiber pattern and laryngeal cancer (OR=0.56, 95% CI: 0.41-0.76). No relationship was evident between the Seed oils pattern and laryngeal cancer (OR=0.98, 95% CI: 0.70-1.37). A direct association was found between the Fish-rich pattern and the laryngeal cancer (OR=2.09, 95% CI: 1.51-2.90).
Conclusions
The role of dietary habits on the risk of laryngeal cancer was evaluated through exploratory PCFA on 28 major nutrients of interest. We identified 5 major dietary patterns, explaining about 80% of the total variance of the original nutrients. Our results indicated that the Animal products and Fish-rich patterns are potentially unfavourable indicators of risk for laryngeal cancer, while the Vitamins and fiber pattern is inversely related to laryngeal cancer
Combinatorial mixtures of multiparameter distributions, with an application to microarray data
The term \u2018combinatorial mixtures\u2019 refers to a flexible class of models for inference on mixture distributions [4] whose components have multidimensional parameters. The idea behind it is to allow each element of component-specific parameter vectors to be shared by a subset of other components.
We develop Bayesian inference and computational approaches for this class of distributions. We define a structure for a general prior distribution where a positive probability is put on every possible combination of sharing patterns, whence the name combinatorial mixtures. This partial sharing allows for generality and flexibility in comparison with traditional approaches to mixture modeling, while still allowing to assign significant mass to models that are more parsimonious than the general mixture case in which no sharing takes place. This also unifies the inference on component-specific parameters with that on the number of components.
We illustrate our combinatorial mixtures in an application based on the normal model. We introduce normal mixture models for univariate and bivariate data, which are amenable to Markov Chain Monte Carlo computing. In the light of combinatorial mixtures, we assume a decomposition of the variance-covariance matrix proposed by Barnard et al. (2000) [1], which separates out standard deviations and correlations, and thus allows to model those parameters separately.
This development was originally motivated by applications in molecular biology, where one deals with continuous measures, such as RNA levels, or protein levels, that vary across unknown biological subtypes. In some cases, subtypes are characterized by an increase in the level of the marker measured, while in others they are characterized by variability in otherwise tightly controlled processes, or by the presence of otherwise weak correlations. Also, several mechanisms can coexist. It may also allow to model an interesting phenomenon observed in microarray analysis when two variables have the same mean and variance but opposite correlations in diseased and normal samples [2]. We use data on molecular classification of lung cancer from the web-based information supporting the published manuscript Garber et al. (2001) [3]
Nutrient dietary patterns and the risk of colorectal cancer : a case-control study from Italy
The role of diet on colorectal cancer has been largely investigated in terms of foods and nutrients, but rarely in terms of dietary patterns. We evaluated the relationship between major dietary patterns and colorectal cancer in an Italian case-control study including 1,225 patients with cancer of the colon, 728 patients with cancer of the rectum, and 4,154 controls, hospitalized for acute non-neoplastic diseases. Dietary habits were investigated through a validated food-frequency questionnaire. We identified dietary patterns on a selected set of nutrients through principal component factor analysis. Odds ratios (OR) and 95% confidence intervals (CI) for both cancer were estimated using unconditional multiple logistic regression models on quintiles of factor scores. We identified 4 major dietary patterns named Animal products, Vitamins and fiber, Unsaturated fats, Strach-rich. No significant association was observed between Animal products pattern and cancer of the colon (OR=0.97, 95% CI: 0.78-1.20, for the highest quintile of factor scores as compared to the lowest), and rectum (OR=1.26, 95% CI: 0.97-1.64). An inverse relationship was found for the Vitamins and fiber pattern and cancer of the rectum (OR=0.68, 95% CI: 0.52-0.88), but not for that of the colon (OR=0.90, 95% CI: 0.73-1.12). A direct association was observed between the Starch-rich pattern and both cancer of the colon (OR=2.10, 95% CI: 1.64-2.68) and rectum (OR=1.93, 95% CI: 1.42-2.63). An inverse association was found for the Unsaturated fats pattern and cancer of the colon (OR=0.89, 95% CI: 0.72-1.10), while no significant association was found for the Unsaturated fats pattern and rectal cancer (OR=1.33, 95% CI: 1.02-1.74)
Are Major a Posteriori Dietary Patterns Reproducible in the Italian Population? A Systematic Review and Quantitative Assessment
Although a posteriori dietary patterns (DPs) naturally reflect actual dietary behavior in a population, their specificity limits generalizability. Among other issues, the absence of a standardized approach to analysis have further hindered discovery of genuinely reproducible DPs across studies from the same/similar populations. A systematic review on a posteriori DPs from principal component analysis or exploratory factor analysis (EFA) across study populations from Italy provides the basis to explore assessment and drivers of DP reproducibility in a case study of epidemiological interest. First to our knowledge, we carried out a qualitative (i.e., similarity plots built on text descriptions) and quantitative (i.e., congruence coefficients, CCs) assessment of DP reproducibility. The 52 selected articles were published in 2001â2022 and represented dietary habits in 1965â2022 from 70% of the Italian regions; children/adolescents, pregnancy/breastfeeding women, and elderly were considered in 15 articles. The included studies mainly derived EFA-based DPs on food groups from food frequency questionnaires and were of âgood qualityâ according to standard scales. Based on text descriptions, the 186 identified DPs were collapsed into 113 (69 food-based and 44 nutrient-based) apparently different DPs (39.3% reduction), later summarized along with the 3 âMmixed-Salad/Vegetable-based Patterns,â âPasta-and-Meat-oriented/Starchy Patterns,â and âDdairy Productsâ and âSsweets/Animal-based Patternsâ groups, by matching similar food-based and nutrient-based groups of collapsed DPs. Based on CCs (215 CCs, 68 DPs, 18 articles using the same input lists), all pairs of DPs showing the same/similar names were at least âfairly similarâ and âŒ81% were âequivalent.â The 30 âequivalentâ DPs ended up into 6 genuinely different DPs (80% reduction) that targeted fruits and (raw) vegetables, pasta and meat combined, and cheese and deli meats. Such reduction reflects the same study design, list of input variables, and DP identification method followed across articles from the same groups. This review was registered at PROSPERO as CRD42022341037
Guidelines by an ad hoc European committe for elective chronic peritoneal dialysis in pediatric patients
Analyzing electronic momentary assessment data on chronic pain and weather conditions : a first look
Although scientific evidence is scarce, patients affected by chronic masticatory muscle pain often report increased pain in response to changes in weather conditions. The aim of the present study was to assess a potential relationship between pain intensity and meteorological factors, through a newly developed, portable device, in this population. Seven female subjects diagnosed with myofascial pain of the masticatory muscles participated in the study. Each patient was provided with a portable data logger that recorded and stored weather variables every 15 minutes. Patients were asked to record the level of perceived pain on an electronic visual analogue scale (VAS) every hour. The relationship between meteorological variables and pain scores was investigated using separate generalized least squares regression models with a correlation structure estimated via autoregressive integrated moving average models
A Bayesian network meta-analysis on the effect of anesthetic drugs in cardiac surgery
We carried out both a pair-wise and a Bayesian network meta-analysis, on 38 randomised trials, to assess how volatile-based anaesthesia (desflurane, isoflurane or sevoflurane) and total intravenous anaesthesia (TIVA) influence patients\u2019 survival after cardiac surgery. A network meta-analysis allow to compare different treatments that were never properly compared. On the basis of statistical inference, it is possible to establish which treatment is superior reaching, through indirect comparison, reliable conclusions otherwise difficult to achieve. The standard meta-analysis showed that the use of a volatile agent was associated with a reduction in mortality when compared to TIVA at the longest follow-up available (25/1994 [1.3%] in the volatile group versus 43/1648 [2.6%] in the TIVA group, odds ratio=0.51, 95% confidence interval 0.33-0.81, p for effect=0.004). The Bayesian network meta-analysis showed that sevoflurane (posterior mean of odds ratio =0.31, 95% credible interval 0.14-0.64) and desflurane (posterior mean of odds ratio =0.43, 95% credible interval 0.21-0.82) were individually associated with a reduction in mortality when compared to TIVA. Anaesthesia with volatile agents appears to reduce mortality after cardiac surgery when compared to TIVA, especially when sevoflurane or desflurane are used
Dietary Patterns in Italy and the Risk of Renal Cell Carcinoma
Background: Conclusive evidence on foods, nutrients, or dietary patterns and the risk of renal cell carcinoma (RCC) is lacking in the literature. Methods: We considered data from an Italian hospital-based case\u2013control study (1992\u20132004) on 767 incident RCC cases and 1534 controls. A posteriori dietary patterns were identified by applying principal component factor analysis on 28 nutrients derived from a 78-item food-frequency questionnaire. We estimated the odds ratios (ORs) of RCC and corresponding 95% confidence intervals (CIs) for each quartile category (compared to the lowest one) using conditional multiple logistic regression models providing adjustment for major confounding factors. Results: We identified four dietary patterns, named \u201cAnimal products\u201d, \u201cStarch-rich\u201d, \u201cVitamins and fiber\u201d, and \u201cCooking oils and dressings\u201d. Higher intakes of the \u201cStarch-rich\u201d pattern were positively associated with RCC risk (OR = 1.38, 95% CI: 1.04\u20131.82 for the highest quartile, p = 0.018). The association was inverse with the \u201cCooking oils and dressings\u201d pattern (OR = 0.61, 95% CI: 0.47\u20130.80, p < 0.001), whereas no association was found with \u201cAnimal products\u201d and \u201cVitamins and fiber\u201d patterns. Conclusions: Higher intakes of starch-related foods may increase RCC risk, whereas consumption of olive and seed oils may favorably influence RCC risk
Vitamin D status among male late adolescents living in Southern Switzerland: Role of body composition and lifestyle
BACKGROUND: Poor vitamin D status is a worldwide health problem. Yet, knowledge about vitamin D status among adolescents in Southern Europe is limited. This study investigated concentrations and modulating factors of vitamin D in a healthy population of male late adolescents living in Southern Switzerland. METHODS: All apparently healthy subjects attending for the medical evaluation before the compulsory military service in Southern Switzerland during 2014-2016 were eligible. Dark-skin subjects, subjects on vitamin D supplementation or managed with diseases or drugs involved in vitamin D metabolism were excluded. Anthropometric measurements (body height, weight, fat percentage, mid-upper arm and waist circumference) and blood sampling for total 25-hydroxy-vitamin D, total cholesterol and ferritin concentrations testing, were collected. Participants filled in a structured questionnaire addressing their lifestyle. Characteristics of the subjects with adequate ( 6550 nmol/L- 64250 nmol/L) and insufficient (<50 nmol/L) vitamin D values were compared by Kruskal-Wallis test or \u3c72 test. Odds ratios for 25-hydroxy-vitamin D insufficiency were calculated by univariate and AIC-selected multiple logistic regression models. RESULTS: A total of 1045 subjects volunteered to participate in the study. Insufficient concentrations of vitamin D were detected in 184 (17%). The season of measurement was the most significant factor associated with vitamin D levels and approximately 40% of subjects presented insufficient vitamin D concentrations in winter. After model selection, body fat percentage, frequency and site of recreational physical activity, and the seasonality were significantly associated with the risk of vitamin D insufficiency. CONCLUSIONS: Among healthy male late adolescents in Southern Switzerland, about one every fourth subject presents a poor vitamin D status in non-summer seasons. Body fat percentage, frequent and outdoor recreational physical activity are modulating factors of vitamin D status in this population
Bronchoalveolar Lavage-microRNAs Are Potential Novel Biomarkers of Outcome after Lung Transplantation
Background. Primary graft dysfunction, infections, and acute rejection (AR) worsen lung transplantation (LTx) outcome and patient survival. Despite significant efforts, reliable biomarkers of acute lung allograft dysfunction are lacking. To address this issue, we profiled the bronchoalveolar lavage (BAL) miRNome in LTx patients. Methods. BAL-microRNAs (miRNAs) from 16 patients were collected 7 days (T0), 15 days (T1), and 3 months (T2) after bilateral LTx and profiled on low-density array. Unsupervised and supervised analyses were used to identify miRNAs associated with clinical features, pneumonia, or AR. Prognostic markers were identified using the Cox model. Targeted signaling pathways were predicted in silico. A second series of 11 patients were used to validate AR-associated miRNAs. Results. Variation in BAL-miRNAs was associated with acute lung allograft dysfunction. Increased levels of miR-23b-3p at T2 were detected in patients with pneumonia, whereas let-7f-5p, miR-146b-3p, miR-22-5p, miR-29c-5p, miR-362-5p, and miR-452-5p were upregulated at T2 in patients with AR. miR-148b-5p and miR-744-3p distinguished LTx patients with AR in both cohorts. Low miR-148b-5p and high miR-744-3p expression levels were significantly associated with a shorter time to AR either within the first year after LTx or during follow-up. Combination of the 2 miRNAs identified LTx patients with higher AR risk independently of clinical variables. Conclusions. Our data provide new insights into the roles of BAL-miRNAs in regulating the pulmonary environment after transplantation and suggest that these miRNAs could serve as biomarkers of early- or mid-stage events. If validated, these findings could pave the way to a personalized clinical approach in LTx patients
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