Androgenic-anabolic steroids use among bodybuilders in western Iran: application of ridge logistic regression model.

INTRODUCTION: Nowadays, the use of androgenic-anabolic steroids (AAS) by competitive and non-competitive bodybuilders and its side effects have become a major public health problem. Many studies have focused on determining the role and severity of various factors in AAS use, but the existence of collinearity between the factors leads to the non-significance of important factors. The study aimed to determine factors affecting the androgenic-anabolic steroids use in Iranian bodybuilders. METHOD: This descriptive-analytical study was performed on 280 male bodybuilders (142 non-competitive and 138 competitive bodybuilders) in Hamadan, west of Iran, in 2016. The participations were recruited a multistage sampling method. A self-administrated questionnaire was used, which included parts such as intrapersonal, interpersonal, and behavioral factors affecting on AAS use. To solve the consequences of collinearity was used ridge logistic regression model (RLRM) in R.3.5.1 software. RESULTS: The mean age of bodybuilders was 25.21 years (SD = 6.31). The prevalence rate of AAS use among non-competitive and competitive bodybuilders was 27.5% and 34.1%, respectively. Factors such as age, time of starting bodybuilding, attitude, physical self-concept, behavioral intention, coach and friend use AAS, alcohol consumption, and supplement use were associated with AAS use among non-competitive and competitive bodybuilders. CONCLUSION: The results of the study indicated that a combination of intrapersonal, interpersonal and behavioral factors was effective on the androgenic-anabolic steroids use among Iranian bodybuilders. Adequate education about the side effects of AAS and improvement of individual skills seem to be helpful in reducing AAS use.

Socio-Cultural Factors Contributing to Being an Organ Donor in Iranian Employees.

AIMS: The purpose of this study was to use a culturally modified Organ Donation Model (ODM) to explore the significant factors and ways in which these factors could influence signing the donor card. METHODS: This cross-sectional study was conducted among 600 employees from 57 offices in Hamadan, Iran, in 2018. Participants were selected randomly and surveyed on being a donor and their perceptions regarding signing the donor card. Structural equation modeling (SEM) was conducted to determine the inter-relationship between the studied variables. RESULTS: Participants' mean age was 39.5 (SD = 7.0). 20% of participants had a signed donor card. Descriptive norms (ß = 0.53, p < 0.001), non-cognitive beliefs (ß=-0.33, p < 0.001), anticipated regret (ß = 0.28, p < 0.001) and subjective norms (ß=-0.17, p < 0.01) had significant direct effects on signing the donor card. CONCLUSION: This study provides socio-culturally informed evidence on individuals' signing donor card. These factors could provide a guide to policymakers to develop the community-based interventions.

Overcoming the problems caused by collinearity in mixed-effects logistic model: determining the contribution of various types of violence on depression in pregnant women.

BACKGROUND: Collinearity is a common and problematic phenomenon in studies on public health. It leads to inflation in variance of estimator and reduces test power. This phenomenon can occur in any model. In this study, a new ridge mixed-effects logistic model (RMELM) is proposed to overcome consequences of collinearity in correlated binary responses. METHODS: Parameters were estimated through penalized log-likelihood with combining expectation maximization (EM) algorithm, gradient ascent, and Fisher-scoring methods. A simulation study was performed to compare new model with mixed-effects logistic model(MELM). Mean square error, relative bias, empirical power, and variance of random effects were used to evaluate RMELM. Also, contribution of various types of violence, and intervention on depression among pregnant women experiencing intimate partner violence(IPV) were analyzed by new and previous models. RESULTS: Simulation study showed that mean square errors of fixed effects were decreased for RMELM than MELM and empirical power were increased. Inflation in variance of estimators due to collinearity was clearly shown in the MELM in data on IPV and RMELM adjusted the variances. CONCLUSIONS: According to simulation results and analyzing IPV data, this new estimator is appropriate to deal with collinearity problems in the modelling of correlated binary responses.

Development and Psychometric Testing of the Signed Donor Card (SDC) Scale in an Islamic Society.

The signed donor card is an important method to overcome the shortage of organs for transplantation. A valid and reliable scale is necessary to have with the development of interventions to increase the signed donor card. This study aimed to develop and psychometric testing of the Signed Donor Card (SDC) in an Islamic society. This methodological study was conducted in Hamadan city, Iran in 2018 on 600 employees of offices. A 46-item scale was developed. It was assessed by face, content, and construct validities. Reliability was examined using the calculation of the Cronbach's α and test-retest method. The SPSS software version 22 and Mplus version 7.4 were used for data analysis. Our scale demonstrated acceptable internal consistency (α = 0.58-0.93) and good test-retest reliability (ICC = 0.76). The fitness indices for the confirmatory factor analysis (CFA) indicated that the model fit was good. CFA revealed nine standalone components including attitude, subjective norms, intention, anticipated regret, descriptive norms, perceived control, knowledge, non-cognitive beliefs, and religious beliefs. Convergent validity and discriminant validity were established. This study provided evidence concerning the validity and reliability of SDC scale. It can be used for the development and implementation of effective interventions for increasing signed donor card with the consideration of contextual and cultural situations.

Differential Effects of Unihemispheric Concurrent Dual-Site and Conventional tDCS on Motor Learning: A Randomized, Sham-Controlled Study.

INTRODUCTION: Based on the literature, unihemispheric concurrent dual-site anodal transcranial Direct Current Stimulation (a-tDCSUHCDS) of primary Motor cortex (M1) and Dorsolateral Prefrontal Cortex (DLPFC) would be more efficient than conventional a-tDCS of M1 to induce larger and longer-lasting M1 corticospinal excitability. The main objective of the present study was to compare the effects of a-tDCSUHCDS and conventional M1 a-tDCS on the extent and durability of the motor sequence acquisition in healthy individuals. METHODS: In this randomized sham-controlled study, healthy volunteers were randomly divided into three groups: experimental (a-tDCSUHCDS), control (M1 a-tDCS), and sham stimulation groups. The participants practiced serial response time task over three consecutive days when they simultaneously received a-tDCS. Using the skill measure, we assessed motor learning up to 4 weeks after the completion of experimental conditions. RESULTS: Data analysis revealed that all groups exhibited the improved trend over the training course (P<0.001). There were no significant differences in skill acquisition among groups at post-intervention (P>0.05), while a significant improvement was observed between experimental and sham group at the retention time (P<0.05). Moreover, there were no significant differences between the control and two other groups with regard to the retention time (P>0.05). CONCLUSION: These results revealed a significant increase in the skill acquisition by a-tDCSUHCDS technique with regard to retention issue, which could be a valuable finding in neuro-rehabilitation field.