A guide to appropriate use of Correlation coefficient in medical research

Correlation is a statistical method used to assess a possible linear association between two continuous variables. It is simple both to calculate and to interpret. However, misuse of correlation is so common among researchers that some statisticians have wished that the method had never been devised at all. The aim of this article is to provide a guide to appropriate use of correlation in medical research and to highlight some misuse. Examples of the applications of the correlation coefficient have been provided using data from statistical simulations as well as real data. Rule of thumb for interpreting size of a correlation coefficient has been provide

Učinak atorvastatina na debljinu arterijske intime medije u bolesnika s ishemijskim moždanim udarom

Occlusion of the initial segment of internal carotid artery is the most common reason for vascular events in the brain. The purpose of this study was to investigate the effect of oneyear treatment with atorvastatin on intima-media thickness (IMT) of carotid arteries as a measure of atherosclerosis in stroke patients. In this prospective interventional study, 44 patients with ischemic stroke were investigated. Patients were treated with atorvastatin 40 mg once a day for one year. IMT of carotid arteries was measured by extracranial Doppler ultrasonography in the distal part of the common carotid artery at the beginning of the study, at 6 months and one year of treatment with atorvastatin. The IMT of both right and left carotid arteries decreased after 6- and 12-month atorvastatin treatment. Based on the results of this study, long-term administration of atorvastatin was associated with reduction in carotid artery IMT in patients with ischemic stroke. Such a decrease in IMT may prevent subsequent stroke or cardiovascular events in these patients.Blokada početnog dijela interne karotidne arterije najčešći je razlog vaskularnih ispada u mozgu. Namjera ovoga istraživanja bila je ispitati učinak jednogodišnje terapije atorvastatinom na debljinu intime medije (intima-media thickness, IMT) karotidnih arterija kao mjere ateroskleroze kod bolesnika s moždanim udarom. U ovoj prospektivnoj intervencijskoj studiji ispitana su 44 bolesnika s ishemijskim moždanim udarom. Bolesnici su liječeni atorvastatinom, 40 mg jedanput na dan kroz jednu godinu. IMT karotidnih arterija mjeren je ekstrakranijskom Doppler ultrasonografijom u distalnom dijelu zajedničke karotidne arterije na početku istraživanja te nakon 6 mjeseci i 12 mjeseci liječenja atorvastatinom. Zabilježeno je sniženje IMT i u desnoj i u lijevoj karotidnoj arteriji nakon 6 mjeseci i 12 mjeseci liječenja atorvastatinom. Rezultati ovoga istraživanja pokazuju da je dugotrajno uzimanje atorvastatina bilo udruženo sa smanjenjem IMT karotidnih arterija u bolesnika s ishemijskim moždanim udarom. Takvo sniženje IMT moglo bi spriječiti naknadni moždani udar ili kardiovaskularne ispade kod ovih bolesnika

Validation of the Thai version of the family reported outcome measure (FROM-16)© to assess the impact of disease on the partner or family members of patients with cancer

© The Author(s). 2019Background: Cancer not only impairs a patient's physical and psychosocial functional behaviour, but also contributes to negative impact on family members' health related quality of life. Currently, there is an absence of a relevant tool in Thai with which to measure such impact. The aim of this study was to translate and validate the Family Reported Outcome Measure (FROM-16) in Thai cancer patients' family members. Methods: Thai version of FROM-16 was generated by interactive forward-backward translation process following standard guidelines. This was tested for psychometric properties including reliability and validity, namely content validity, concurrent validity, known group validity, internal consistency, exploratory and confirmatory factor analysis. Construct validity was examined by comparing the Thai FROM-16 version with the WHOQOL-BREF-THAI. Results: The internal consistency reliability was strong (Cronbach's alpha = 0.86). A Negative moderate correlation between the Thai FROM-16 and WHOQOL-BREF-THAI was observed (r = - 0.4545, p < 0.00), and known group validity was proved by a statistically significant higher score in family members with high burden of care and insufficient income. The factor analysis supported both 3-factor and 2-factor loading model with slight difference when compared with the original version. Conclusions: The Thai FROM-16 showed good reliability and validity in Thai family members of patients with cancer. A slight difference in factor analysis results compared to the original version could be due to cross-culture application.Peer reviewedFinal Published versio

Cross-cultural adaptation of children´s environmental health questionnaires for English nursing students

Objectives: Children are among the most vulnerable population groups with regard to environmental risks. Nursing students must be fully educated on children’s environmental health as they are in a key position to prevent and reduce the effects of environmental hazards. The main objective of this study was to adapt and validate an English language version of two questionnaires about children’s health and the environment, to assess the knowledge and skills of student nurses in England. Design: Observational cross-sectional study. Setting: A university in Southern England. Method: The study involves translating, adapting and validating the Children’s Environmental Health Knowledge Questionnaire (ChEHK-Q) and the Children’s Environmental Health Skills Questionnaire (ChEHS-Q) with nursing students in England (N = 232). Results: The psychometric characteristics of both questionnaires were strong. Infit and outfit values were close to 1. The reliability values for the items and people were 0.96 and 0.79 for ChEHK-Q and 0.98 and 0.89 for ChEHS-Q, respectively. Only 52 (22.41%) and 77 (33.62%) participants had at least good knowledge and skills, respectively. Higher knowledge and skills were found with respect to the vulnerability of children and identification of environmental risks in the home. Lower levels of knowledge and skills were found with respect to the effects of pesticides and the assessment of neoplastic pollutants. Conclusion: Findings demonstrate deficiencies in nursing competencies related to children’s environmental health. The use of these questionnaires will facilitate improvement in both knowledge and skills related to children’s environmental health among future nurses

SELECTIVE MEASUREMENT OF α SMOOTH MUSCLE ACTIN: WHY β-ACTIN CAN NOT BE USED AS A HOUSEKEEPING GENE WHEN TISSUE FIBROSIS OCCURS

Abstract Background Prevalence of fibroproliferative diseases, including chronic kidney disease is rapidly increasing and has become a major public health problem worldwide. Fibroproliferative diseases are characterized by increased expression of α smooth muscle actin (α-SMA) that belongs to the family of the six conserved actin isoforms showing high degree homology. The aim of the present study was to develop real-time PCRs that clearly discriminate α-SMA and ß-actin from other actin isoforms. Results Real-time PCRs using self-designed mouse, human and rat specific α-SMA or ß-actin primer pairs resulted in the specific amplification of the artificial DNA templates corresponding to mouse, human or rat α-SMA or ß-actin, however ß-actin showed cross-reaction with the housekeeping γ-cyto-actin. We have shown that the use of improperly designed literary primer pairs significantly affects the results of PCRs measuring mRNA expression of α-SMA or ß-actin in the kidney of mice underwent UUO. Conclusion We developed a set of carefully designed primer pairs and PCR conditions to selectively determine the expression of mouse, human or rat α-SMA and ß-actin isoforms. We demonstrated the importance of primer specificity in experiments where the results are normalized to the expression of ß-actin especially when fibrosis and thus increased expression of α-SMA is occur

A MATLAB app to assess, compare and validate new methods against their benchmarks

Emerging technologies for physiological signals and data collection enable the monitoring of patient health and well-being in real-life settings. This re-quires novel methods and tools to compare the validity of this kind of in-formation with that acquired in controlled environments using more costly and sophisticated technologies. In this paper, we describe a method and a MATLAB tool that relies on a standard sequence of statistical tests to com-pare features obtained using novel techniques with those acquired by means of benchmark procedures. After introducing the key steps of the proposed statistical analysis method, this paper describes its implementation in a MATLAB app, developed to support researchers in testing the extent to which a set of features, captured with a new methodology, can be considered a valid surrogate of that acquired employing gold standard techniques. An example of the application of the tool is provided in order to validate the method and illustrate the graphical user interface (GUI). The app develop-ment in MATLAB aims to improve its accessibility, foster its rapid adoption among the scientific community and its scalability into wider MATLAB tools

Effects of Wind Speed and Direction on Monthly Fluctuations of Cladosporium Conidia Concentration in the Air

This study determined the relationship between airborne concentration of Cladosporium spp. spores and wind speed and direction using real data (local wind measured by weather station) and modelled data (air mass flow computed with the aid of HYbrid Single Particle Lagrangian Trajectory model). Air samples containing fungal conidia were taken at an urban site (Worcester, UK) for a period of five consecutive years using a spore trap of the Hirst design. A threshold of ≥6000 s m−3 (double the clinical value) was applied in order to select high spore concentration days, when airborne transport of conidia at a regional scale was more likely to occur. Collected data were then examined using geospatial and statistical tools, including circular statistics. Obtained results showed that the greatest numbers of spore concentrations were detected in July and August, when C. herbarum, C. cladosporioides and C. macrocarpum sporulate. The circular correlation test was found to be more sensitive than Spearman’s rank test. The dominance of either local wind or the air mass on Cladosporium spore distributions varied between examined months. Source areas of this pathogen had an origin within the UK territory. Very high daily mean concentrations of Cladosporium spores were observed when daily mean local wind speed was vs ≤ 2.5 m s−1 indicating warm days with a light breeze