Showing papers by "Bruno de Sousa published in 2017"

Plasmodium falciparum Genetic Diversity in Continental Equatorial Guinea before and after Introduction of Artemisinin-Based Combination Therapy.

Abstract: Efforts to control malaria may affect malaria parasite genetic variability and drug resistance, the latter of which is associated with genetic events that promote mechanisms to escape drug action. The worldwide spread of drug resistance has been a major obstacle to controlling Plasmodium falciparum malaria, and thus the study of the origin and spread of associated mutations may provide some insights into the prevention of its emergence. This study reports an analysis of P. falciparum genetic diversity, focusing on antimalarial resistance-associated molecular markers in two socioeconomically different villages in mainland Equatorial Guinea. The present study took place 8 years after a previous one, allowing the analysis of results before and after the introduction of an artemisinin-based combination therapy (ACT), i.e., artesunate plus amodiaquine. Genetic diversity was assessed by analysis of the Pfmsp2 gene and neutral microsatellite loci. Pfdhps and Pfdhfr alleles associated with sulfadoxine-pyrimethamine (SP) resistance and flanking microsatellite loci were investigated, and the prevalences of drug resistance-associated point mutations of the Pfcrt, Pfmdr1, Pfdhfr, and Pfdhps genes were estimated. Further, to monitor the use of ACT, we provide the baseline prevalences of K13 propeller mutations and Pfmdr1 copy numbers. After 8 years, noticeable differences occurred in the distribution of genotypes conferring resistance to chloroquine and SP, and the spread of mutated genotypes differed according to the setting. Regarding artemisinin resistance, although mutations reported as being linked to artemisinin resistance were not present at the time, several single nucleotide polymorphisms (SNPs) were observed in the K13 gene, suggesting that closer monitoring should be maintained to prevent the possible spread of artemisinin resistance in Africa.

Risk factors for pathological gambling along a continuum of severity: Individual and relational variables

Abstract: This study’s aim was to identify characteristics with higher odds of distinguishing a group of pathological gamblers (PG) from (1) a group of gamblers without a gambling problem (NP) and 2) a sub-clinical group (SP). An additional aim was to investigate those characteristics as risk/protective factors along the continuum of problem-gambling severity. Sociodemographic (gender, age, marital status, and educational level), individual (psychopathological symptoms) and relational (family functioning, dyadic adjustment, and differentiation of self) variables were considered. The sample consisted of 331 participants: 162 NP, 117 SP and 52 PG. The main results indicate that the characteristics with higher odds of distinguishing among the groups were gender, educational level, age, differentiation of self, and psychopathological symptoms. The odds of being a PG were higher for men with a low educational level and less adaptive psycho-relational functioning. Conversely, the odds of being a NP were higher for women with a high educational level and more adaptive psycho-relational functioning. Gender and educational level stood out with respect to their relevance as risk/protective factors, and their role was found to be dynamic and interdependent with the severity of problem gambling and/or the investigated psycho-relational characteristics. The risk/protective value was more remarkable when gamblers already exhibited SP. L’objectif de cette etude etait d'identifier les caracteristiques presentant une probabilite plus elevee de distinguer un groupe de joueurs pathologiques (PG) d'un groupe de joueurs sans probleme de jeu (NP) et un groupe sous-clinique (SP). Un autre objectif consistait a etudier ces caracteristiques en tant que facteurs de risque / protection dans le continuum de la gravite du jeu problematique. Les variables sociodemographiques (sexe, âge, etat matrimonial et niveau d'instruction), individuelles (symptomes psychopathologiques) et relationnelles (fonctionnement familial, ajustement dyadique et differenciation de self) ont ete prises en consideration. L'echantillon comprenait 331 participants: 162 NP, 117 SP et 52 PG. Les principaux resultats indiquent que les caracteristiques ayant une plus grande probabilite de distinction entre les groupes etaient le sexe, le niveau d'instruction, l'âge, la differenciation de self et les symptomes psychopathologiques. Les probabilites d'etre un PG etaient plus elevees chez les hommes ayant un faible niveau d'instruction et moins adaptative au fonctionnement psycho-relationnel. A l'inverse, les probabilites d'etre NP etaient plus elevees chez les femmes ayant un niveau d'instruction eleve et un fonctionnement psycho-relationnel plus adaptatif. Le sexe et le niveau de scolarite se distinguent par leur pertinence en tant que facteurs de risque / protection et leur role est juge dynamique et interdependant de la gravite du jeu problematique et / ou des caracteristiques psycho-relationnel etudiees. La valeur risque / protection etait plus remarquable lorsque les joueurs presentaient deja SP.

Studying the relationship between a woman's reproductive lifespan and age at menarche using a Bayesian multivariate structured additive distributional regression model

Abstract: Studies addressing breast cancer risk factors have been looking at trends relative to age at menarche and menopause. These studies point to a downward trend of age at menarche and an upward trend for age at menopause, meaning an increase of a woman's reproductive lifespan cycle. In addition to studying the effect of the year of birth on the expectation of age at menarche and a woman's reproductive lifespan, it is important to understand how a woman's cohort affects the correlation between these two variables. Since the behavior of age at menarche and menopause may vary with the geographic location of a woman's residence, the spatial effect of the municipality where a woman resides needs to be considered. Thus, a Bayesian multivariate structured additive distributional regression model is proposed in order to analyze how a woman's municipality and year of birth affects a woman's age of menarche, her lifespan cycle, and the correlation of the two. The data consists of 212,517 postmenopausal women, born between 1920 and 1965, who attended the breast cancer screening program in the central region of Portugal.

Exploring risk factors in breast cancer screening program data using structured geoadditive models with high order interaction

Abstract: When analyzing data from cancer screening programs, flexible regression specifications are required to account for the highly complex structure in such data. We analyzed data from a breast cancer screening program conducted in central Portugal and considered an extension of structured additive regression models where, in addition to the possibility to include nonlinear and spatial effects, we can include a trivariate interaction between attendance rate, detection rate and mortality rate in the screening program. While spatial effects capture unobserved heterogeneity at the municipality level, the trivariate interaction proves important for the understanding of the complex interaction effects resulting from the diversity in municipality coverage and attendance rates. The trivariate interaction is implemented based on a Markov random field representation which enables efficient Bayesian inference and, when modeling breast cancer incidence rates, showed a significant improvement in terms of model fit when compared to a simpler geoadditive regression model.

Applying Spatial Copula Additive Regression to Breast Cancer Screening Data

Abstract: Breast cancer is associated with several risk factors. Although genetics is an important breast cancer risk factor, environmental and sociodemographic characteristics, that may differ across populations, are also factors to be taken into account when studying the disease. These factors, apart from having a role as direct agents in the risk of the disease, can also influence other variables that act as risk factors. The age at menarche and the reproductive lifespan are considered by the literature as breast cancer risk factors so that, there are several studies whose aim is to analyze the trend of age at menarche and menopause along generations. Also, it is believed that these two moments in a woman’s life can be affected by environmental, social status, and lifestyles of women. Using the information of 278,282 registries of women which entered in the breast cancer screening program in Central Portugal, we developed a bivariate copula model to quantify the effect a woman’s year of birth in the association between age at menarche and a woman’s reproductive lifespan, in addition to explore any possible effect of the geographic location in these variables and their association. For this analysis we employ Copula Generalized Additive Models for Location, Scale and Shape (CGAMLSS) models and the inference was carried out using the R package SemiParBIVProbit.