Understanding logistic regression analysis

Logistic regression is used to obtain odds ratio in the presence of more than one explanatory variable. The procedure is quite similar to multiple linear regression, with the exception that the response variable is binomial. The result is the impact of each variable on the odds ratio of the observed event of interest. The main advantage is to avoid confounding effects by analyzing the association of all variables together. In this article, we explain the logistic regression procedure using examples to make it as simple as possible. After definition of the technique, the basic interpretation of the results is highlighted and then some special issues are discussed

The pits and falls of graphical presentation

Graphics are powerful tools to communicate research results and to gain information from data. However, researchers should be careful when deciding which data to plot and the type of graphic to use, as well as other details. The consequence of bad decisions in these features varies from making research results unclear to distortions of these results, through the creation of “chartjunk” with useless information. This paper is not another tutorial about “good graphics” and “bad graphics”. Instead, it presents guidelines for graphic presentation of research results and some uncommon, but useful examples to communicate basic and complex data types, especially multivariate model results, which are commonly presented only by tables. By the end, there are no answers here, just ideas meant to inspire others on how to create their own graphics

INVESTIGATING THE DIFFERENCES BETWEEN BEGINNERS AND ADVANCED CLIMBERS

The aim of this study is to identify the differences in the movement patterns of beginners and advanced climbers, according to quantitative parameters. In order to do so, climbers (n=17) of a variety of skill levels were analyzed as they climbed up the test routes. From this, the following conclusions were drawn: beginner climbers (n=11) require very much the aid of tactic and visual information to elaborate their responses, whereas more experienced climbers (n=6) are able to anticipate their response only with the aid of visual information. This characteristic was conveyed through the greater amount of hand movements performed by the beginners, as well as a longer period of time required to ascend the test routes

ELECTROMYOGRAPHIC COMPARISON OF THE UPPER AND LOWER RECTUS ABDOMINIS DURING ABDOMINAL EXERCISES

The purpose of this study was a comparative EMG analysis of three abdominal exercises in the activation of superior and inferior portions of rectus abdominis muscle. Young healthy adults (n=20) were analysed during the exercises by electromyography. All exercises were performed in a surface with 150 inclination. Two-Way Repeated Measures ANOVA was used to compare exercise and phase (conc. X exc.). Results shown that each portion was more active in inverse exercise with pelvic tilt, probably because it’s higher intensity. Intensity of exercise seems to be more important than variation in activate abdominal muscle

PREVALÊNCIA DE LESÕES E SUAS IMPLICAÇÕES EM UM MURO DE ESCALADA INDOOR

Descrever a prevalncia de leses possivelmente relacionadas escalada e suas implicaes em um muro de escalada de uma academia. Materiais e Mtodos: De 540 freqentadores de um muro de escalada, foram selecionados 27 indivduos para responder um questionrio sobre leses e seus hbitos de escalada. Os critrios mnimos de incluso foram: ter escalado dois meses seguidos, com 23 dias de escalada e mdia de cinco dias de escalada por ms. Sete indivduos no puderam ser encontrados no perodo do estudo. Os 20 indivduos remanescentes apresentavam 19,4 anos (9,3) e nvel tcnico entre IV e 7a. Resultados: A prevalncia de leses em sete meses foi de 80%. A mo foi o principal local de leso (75% - direita, 56% - esquerda). Devido dor, 50% pararam de escalar, em mdia, por seis dias e 31% reduziram outras atividades fsicas, em mdia, por 4,4 dias. A crioterapia foi o principal tratamento utilizado (31%). Mtodos de preveno foram adotados por 68,75% dos indivduos. Concluses: Mesmo em poucos meses, a prevalncia de leses alta, sendo a mo o local mais afetado. Mais pesquisas so necessrias em relao ao treinamento com o objetivo de minimizar a prevalncia de leses em escalada

Employment transitions and mental health in a cohort of 45 years and older Australians

Background: This study investigated the associations between employment transitions and psychological distress among a cohort of 45 years and older Australians. Methods: This study was based on the 45 and Up Study, a large prospective cohort of participants aged 45 years and older (N = 267,153), followed up over the period 2006–2015. The risk of psychological distress was compared between various employment transitions categories by specifying an ordered logistic regression model adjusting for confounders. Results: Compared to participants who remained employed at baseline and follow-up, higher psychological distress was found among those who transitioned from being employed to unemployed (OR = 2.68, 95%CI 2.13–3.33) and to not being in the labour force or retired (OR = 2.21, 95%CI 1.85–2.62). Higher psychological distress was also evident among those who remained unemployed from baseline to follow-up (OR = 2.00, 95%CI 1.10–3.43), and those who transitioned from being retired to being unemployed (OR = 1.55, 95%CI 1.03–2.27). Conversely, lower psychological distress was found among those who transitioned from being unemployed to being employed (OR = 0.35, 95%CI 0.25–0.51). In general, lower psychological distress was found among ‘positive’ employment transitions (transitioning to being employed or retired). Conclusions: Policies focussing on re-employment in older age, as well as unemployment schemes, might be helpful in reducing psychological distress among middle-and old-age Australians

The long-term outcomes of mental health first aid training for university students

This study aimed to address current gaps in the literature on the impacts of Mental Health First Aid (MHFA) training by comparing long-term outcomes on diferent cohorts. University students studying health and non-health degrees, university staf and community members who had completed MHFA within the past three years completed a survey to assess their mental health literacy, and their use of knowledge and skills acquired through the training. The study found few signifcant diferences between the diferent group outcomes and between diferent time points post-completion of MHFA. This study found that although participant-reported measures show positive outcomes from MHFA, further research on the common tools used to rate mental health literacy and how mental health literacy impacts behaviours and help-seeking would provide greater insight into the outcomes of running MHFA as a mental health prevention and early intervention program at universities

Repeatability of the evaluation of systemic microvascular endothelial function using laser doppler perfusion monitoring: clinical and statistical implications

OBJECTIVE: An awareness of the repeatability of biological measures is required to properly design and calculate sample sizes for longitudinal interventional studies. We investigated the day-to-day repeatability of measures of systemic microvascular reactivity using laser Doppler perfusion monitoring. METHODS: We performed laser Doppler perfusion monitoring in combination with skin iontophoresis using acetylcholine and sodium nitroprusside as well as post-occlusive reactive and thermal hyperemia twice within two weeks. The repeatability was assessed by calculating the within-subject standard deviations, limits of agreement, typical errors and intra-class correlation coefficients between days 1 and 2. The ratio of the within-subject standard deviation to the mean values obtained on days 1 and 2 (within-subject standard deviation/GM) was used to determine the condition with the best repeatability. RESULTS: Twenty-four healthy subjects, aged 24.6 + 3.8 years, were recruited. The area under the curve of the vasodilatory response to post-occlusive reactivity showed marked variability (within-subject standard deviation/GM = 0.83), while the area under the curve for acetylcholine exhibited less variability (within-subject standard deviation/ GM = 0.52) and was comparable to the responses to sodium nitroprusside and thermal treatment (within-subject standard deviations/GM of 0.67 and 0.56, respectively). The area under the blood flow/time curve for vasodilation during acetylcholine administration required the smallest sample sizes, the area under the blood flow/time curve during post-occlusive reactivity required the largest sample sizes, and the area under the blood flow/time curves of vasodilation induced by sodium nitroprusside and thermal treatment required intermediate sizes. CONCLUSIONS: In view of the importance of random error related to the day-to-day repeatability of laser Doppler perfusion monitoring, we propose an original and robust statistical methodology for use in designing prospective clinical studies