Research Articles (Statistics & Population Studies)
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Item Pre-race self-reported medical conditions and allergies in 133 641 Comrades ultramarathon (90km) runners - SAFER XXIII(The Physician and Sportsmedicine, 2023) Jordaan, Esme; Brill, Stephan; Schwellnus, Martin; Sewry, NicolaObjectives: To determine the prevalence of self-reported pre-race chronic medical conditions and allergies in ultramarathon race entrants and to explore if these are associated with an Increased risk of race-day medical encounters (MEs). Methods: Data from two voluntary open-ended pre-race medical screening questions (Q1 – history of allergies; Q2 - history of chronic medical conditions/prescription medication use) were collected in 133 641 Comrades Marathon race entrants (2014-2019). Race-day ME data collected prospectively over 6 years are reported as incidence (per 1000 starters) and incidence ratios (IR: 95%CI’s).Item Global warming and psychotraumatology of natural disasters: the case of the deadly rains and floods of April 2022 in South Africa(Annales Médico-psychologiques, revue psychiatrique, 2023) Bouchard, Jean-Pierre; Pretorius, Tyrone B; Kramers-Olen, Anne LClimate change and global warming have led to an increased incidence of flooding across the world. Against the backdrop of the recent devastating floods in the Kwazulu-Natal province of South Africa, this paper explores psychotraumatology of natural disasters. In particular, we explore the impact of internal migration in South Africa, as well as apartheid spatial planning and inequality on the consequences of the flooding. We also focus on the psychotraumatology resulting from flooding, in general, and in particular on the victims of the flooding in the KwaZulu-Natal province of South Africa. We conclude that the psychopathological consequences of such natural disasters are ignored even though they seriously affect the people concerned. The development of specific trainings for psychologists in psychotraumatology and the care of victims should be a priority in the future.Item Boys or girls? Sex preferences declared in African and South-Asian demographic surveys(Elsevier, 2023) Garenne, Michel; Stiegler, Nancy; Bouchard, Jean-PierreIn this interview with Jean-Pierre Bouchard, demographers Michel Garenne and Nancy Stiegler explore sex-preferences for girls or for boys expressed by women who responded to DHS surveys in 29 African and 10 Asian countries. The IPUMS/DHS database was used for statistical analysis, bringing together 140 surveys and 2.5 million women aged 15–49. Overall, two-thirds of women were in favor of a balanced number of girls and boys or were indifferent to the composition of the family. In 20.8% of cases, they preferred to have more boys, and in 12.6% of cases they preferred to have more girls. These proportions vary considerably between countries, and were influenced by local culture, religion, level of education, household wealth, and to a small extent by urban residence. Sex preferences were also influenced by family composition. These preferences are likely to change rapidly over time. Among the countries analyzed, eight expressed preferences for more girls, all located in sub-Saharan Africa, and particularly in southern Africa. These preferences could have many consequences, demographic, psychological and social.Item Causes and patterns of morbidity and mortality in Afghanistan: Joint estimation of multiple causes in the neonatal period(Springer, 2014) Adegboye, Oyelola A.; Kotze, DanelleThis paper focuses on investigating the leading cause(s) of death and preventable factors in Afghanistan, using data from verbal autopsies of infant deaths. We are of the view that the presence of a disease in a person may increase the risk of another disease that may contribute to the death process. The influence of individual- and community-level variables on infant morbidity and mortality in Afghanistan is examined. The results of this study suggest the existence of multiple causes of death in the Afghanistan Mortality Survey (AMS). In Afghanistan, complications of pregnancy are clearly a problem and must be adequately improved.Item On multiple classes of gamma-ray bursts, as deduced from autocorrelation functions or bivariate duration/hardness ratio distributions(Oxford University Press, 2012) Koen, C; Bere, AAutocorrelation functions (ACFs) of 119 gamma-ray bursts (GRBs) monitored by the Burst Alert Telescope (BAT) on Swift are calculated. Contrasting with previous results for smaller numbers of bursts from other missions, the widths of the ACFs are not bimodally distributed. Although the distribution appears slightly asymmetrical, underlying mixtures of distributions can also probably be ruled out. Factors contributing to differences between the results presented here, and those in the literature, may include the differences in energy passbands used, and the superior sensitivity of the BAT instrument (which affects e.g. the redshift distribution of the detected GRB). The second part of the paper is concerned with the fitting of mixtures of bivariate Gaussians to the joint duration/hardness ratio data of 325 GRBs. A careful analysis confirms that a three-component mixture is the statistically most acceptable, but it is shown that the implied marginal distribution of the hardness ratios does not fit the data very well. It is also stressed that mixture components cannot automatically be assumed to represent different classes of GRBs. The point is illustrated by showing two substantially different, but statistically almost equivalent, mixture models for the distribution of 571 BAT-determined GRB durations.Item Symptom number and reduced preinfection training predict prolonged return to training after sars-cov-2 in athletes: Aware IV(Lippincott, Williams & Wilkins, 2023) Snyders, Carolette; Schwellnus, Martin; Jordaan, EsmeSymptom Number and Reduced Preinfection Training Predict Prolonged Return to Training after SARS-CoV-2 in Athletes: AWARE IV. Med. Sci. Sports Exerc., Vol. 55, No. 1, pp. 1-8, 2023. Purpose: This study aimed to determine factors predictive of prolonged return to training (RTT) in athletes with recent SARS-CoV-2 infection. Methods: This is a cross-sectional descriptive study. Athletes not vaccinated against COVID-19 (n = 207) with confirmed SARS-CoV-2 infection (predominantly ancestral virus and beta-variant) completed an online survey detailing the following factors: demographics (age and sex), level of sport participation, type of sport, comorbidity history and preinfection training (training hours 7 d preinfection), SARS-CoV-2 symptoms (26 in 3 categories; “nose and throat,” “chest and neck,” and “whole body”), and days to RTT. Main outcomes were hazard ratios (HR, 95% confidence interval) for athletes with versus without a factor, explored in univariate and multiple models. HR < 1 was predictive of prolonged RTT (reduced % chance of RTT after symptom onset). Significance was P < 0.05. Results: Age, level of sport participation, type of sport, and history of comorbidities were not predictors of prolonged RTT.Item Trauma and PTSD in prisons and corrections(Elsevier, 2023) Fovet, Thomas; Villa, Clément; Bouchard, Jean-PierrePost-traumatic stress disorder (PTSD), and particularly complex PTSD, is over-represented in prisons and corrections. In this interview with Jean-Pierre Bouchard, Thomas Fovet, Cle ́ ment Villa, Bettina Belet, Fanny Carton, Timothe ́ e Bauer, Suzanne Buyle-Bodin and Fabien D’Hondt draw on their clinical experience and recent epidemiological research to provide an overview of the issue. The clinical aspects specifically found in the prison environment, especially the questions of comorbid psychiatric and substance use disorders or PTSD in perpetrators of violent crime, are developed. The current state of knowledge regarding the management of post-traumatic symptoms in prison is also discussed and put into perspective with daily practice.Item Factors associated with patellofemoral pain in recreational road cyclists: A cross-sectional study in 59953 cyclists – SAFER XXXIII(Elsevier, 2023) du Toit, François; Schwellnus, Martin; Jordaan, EsmePatellofemoral pain (PFP) is a common cycling-related injury, and independent factors need to be identified to enable effective injury prevention strategies. We aim to determine factors associated with PFP in cyclists entering mass community-based events. 62758 consenting race entrants completed a pre-race medical questionnaire, and 323 reported PFP. Selected factors associated with PFP (demographics, cycling experience and training, chronic disease history) were explored using multivariate analyses.Item Incidence and burden of injury at the Tokyo 2020 Paralympic Games held during the Covid-19 pandemic: A prospective cohort study of 66 045 athlete days(British Journal of Sports Medicine, 2022) Derman, Wayne; Runciman, Phoebe; Jordaan, EsmeObjective To describe the epidemiology of injuries at the Tokyo 2020 Paralympic Games, including injuries sustained in the new sports of badminton and taekwondo. Methods Injury data were obtained daily via the established web-based injury and illness surveillance system (WEB-IISS; 81 countries, 3836 athletes) and local organizing committee medical facilities (81 countries, 567 athletes).Item What are psychiatric disorders of people who are incarcerated in France(Elsevier, 2022) Bouchard, Jean-PierreThe presence of detainees suffering from psychiatric disorders has been observed since the birth of the modern prison system, and the numbers have fluctuated since then, depending on the evolution of psychiatric facilities and the French legislative framework. As of January 1, 2022, almost 70,000 people were incarcerated in the 187 French correctional institutions in metropolitan and overseas France. Many psychiatric disorders are over-represented in the correctional population compared to the general population, and they include disorders such as depressive, psychotic, bipolar, post-traumatic stress, and substance abuse disorders together with neurodevelopmental disorders such as attention deficit disorder with/without hyperactivity. In this interview with Jean-Pierre Bouchard, Thomas Fovet and Marion Eck discuss this phenomenon based on recent epidemiological data and their personal experience. Some specific clinical aspects of psychiatry in the correctional environment are also discussed.Item Examining inequality of opportunity in the use of maternal and reproductive health interventions in Sierra Leone(Oxford University Press, 2020) Tsawe, Mluleki; Susuman, A. SathiyaPoor countries, such as Sierra Leone, often have poor health outcomes, whereby the majority of the population cannot access lifesaving health services. Access to, and use of, maternal and reproductive health services is crucial for human development, especially in developing regions. However, inequality remains a persistent problem for many developing countries. Moreover, we have not found empirical studies, which have examined inequalities in maternal and reproductive health in Sierra Leone.Item A weighted bootstrap approach to logistic regression modelling in identifying risk behaviours associated with sexual activity(Taylor and Francis Group, 2019) Brydon, Humphrey; Blignaut, Rénette; Jacobs, JoachimThe latest population estimates released by Statistics South Africa indicate that 25.03% of alldeaths in 2017 in South Africa were AIDS-related. Along with these results, it is also reportedthat 7.06% of the population were living with HIV, with the HIV-prevalence among youth(aged 15–24) at 4.64% for 2017 (STATSSA. (2018). Retrieved from Statistics South Africa:http://www.statssa.gov.za/publications/P0302/P03022017.pdf). The data used in the studycontained information related to the risk-taking behaviours associated with the sexualactivity of enteringfirst-year students at the University of the Western Cape. In this study, alogistic regression modelling procedure was carried out on those students that weredetermined to be sexually active, therefore, in the modelling procedure significant riskbehaviours of sexually activefirst-year students could be identified. Of the 14 variablesincluded in the modelling procedure, six were found to be significantly associated withsexually active students.Item Trends in HIV risk behaviour of incoming first-year students at a South African university: 2007–2012(Taylor and Francis Group, 2015) Blignaut, Renette J.; Jacobs, Joachim; Vergnani, TaniaThe aim of the research on which this article is based was to understand the behavioural changes of the target student populationover time to ensure that future prevention programmes are more effective in changing behaviour. This study reports on quantitativedata collected at the University of the Western Cape over a six-year period between 2007 and 2012. All the students attending theorientation sessions and who were willing to complete the anonymous questionnaire during each of the six years were included inthe study. Data were collected on the following aspects and subjects: sexual activity, age at first sexual encounter, number of sexualpartners, condom usage, knowledge of how to use a condom, perceived ability to discuss condoms usage with a sexual partner,perception of HIV risk and HIV testing as well as the intention to be tested. Reported alcohol and drug usage, as well asdepressive symptoms, was also recorded. The percentage of students reporting having had vaginal sex prior to enteringuniversity increased from 44% in 2007 to 51% in 2012 but, alarmingly, the consistent use of condoms decreased from 60% in2007 to 51% in 2012. The average onset age of about 15.6 years for males and 16.7 years for females for vaginal sex did notchange over the six-year period. No difference in smoking patterns or drug use was seen over the period of the study, but thenumber of entering students who indicated that they consumed alcohol increased significantly from 48% in 2007 to 58% in2012.Item Correlates of gender characteristics, health and empowerment of women in Ethiopia(BMC, 2015) Lailulo, Yishak Abraham; Susuman, A Sathiya; Blignaut, RenetteThe low status of women prevents them from recognizing and voicing their concerns about health needs. This study aimed to examine the relationship between gender characteristics, health and empowerment of women in an attempt to understand between 2005 and 2011. Data from the Ethiopia Demographic and Health Survey (EDHS) 2005 and 2011 were used. Bivariate and multivariate analyses were used to determine the relative contribution of the predictor variables. The hypotheses tested in this study were that gender (men and women), health and empowerment of women in region are highly significant with women’s education and work status. Study findings showed that the low status of women and their disempowerment are highly associated with poor health outcomes. In both 2005 and 2011 men school ages were positively associated with their attainment in primary education, whereas for women it was negatively related with their attainment in some education. In both 2005 and 2011 women in the richest wealth quintile had the highest odds ratio of relating to some education.Item Menstrual regulation: Examining the incidence, methods, and sources of care of this understudied health practice in three settings using cross-sectional population-based surveys(BMC, 2023) Bell, Suzanne O.; Shankar, Mridula; Omoluabi, ElizabethMenstrual regulation is a practice that may exist within the ambiguity surrounding one’s pregnancy status and has been the subject of limited research. The aim of this study is to measure the annual rate of menstrual regulation in Nigeria, Cote d’Ivoire, and Rajasthan, India, overall and by background characteristics and to describe the methods and sources women use to bring back their period. Data come from population-based surveys of women aged 15–49 in each setting. In addition to questions on women’s background characteristics, reproductive history, and contraceptive experiences, interviewers asked women whether they had ever done something to bring back their period at a time when they were worried they were pregnant, and if so, when it occurred and what methods and source they used. A total of 11,106 reproductiveaged women completed the survey in Nigeria, 2,738 in Cote d’Ivoire, and 5,832 in Rajasthan. We calculated one-year incidence of menstrual regulation overall and by women’s background characteristics separately for each context using adjusted Wald tests to assess signifcant. We then examined the distribution of menstrual regulation methods and sources using univariate analyses.Item Multiple imputation of unordered categorical missing data: A comparison of the multivariate normal imputation and multiple imputation by chained equations(Brazilian Statistical Association, 2016) Karangwa, Innocent; Kotze, Danelle; Blignaut, Renette. Missing data are common in survey data sets. Enrolled subjects do not often have data recorded for all variables of interest. The inappropriate handling of them may negatively affect the inferences drawn. Therefore, special attention is needed when analysing incomplete data. The multivariate normal imputation (MVNI) and the multiple imputation by chained equations (MICE) have emerged as the best techniques to deal with missing data. The former assumes a normal distribution of the variables in the imputation model and the latter fills in missing values taking into account the distributional form of the variables to be imputed. This study examines the performance of these methods when data are missing at random on unordered categorical variables treated as predictors in the regression models. First, a survey data set with no missing values is used to generate a data set with missing at random observations on unordered categorical variables.Item HE 0230–4323: An unusual pulsating hot subdwarf star(Oxford University Press, 2007) Koen, ChrisHE 0230−4323 is a known binary, consisting of a subdwarf star and a companion which is not observable in the optical. Photometric measurements reported in this paper have shown it to be both a reflection-effect and a pulsating variable. The dominant pulsation frequencies changed over the course of several nights of observing, from ∼32–39 d−1 to ∼8–16 d−1. Observations were obtained through B and V filters, and the variations in the two wavebands appear to be approximately 180◦ out of phase.Item Is Swaziland on track with the 2015 millennium development goals?(SAGE Publications, 2017) Susuman, A SathiyaAccording to the Millennium Development Goals (MDGs) agreement, each participating country has to periodically provide a report that will show the progress on their achievement towards the goals. This article’s aim is to evaluate Swaziland’s prospects of achieving eight MDGs by 2015. This article is an analysis of the current situation of Swaziland, and the aim of this analysis is to look beyond the statistical values to see if the achievements (including lifetime achievements) are on track and whether what is yet to be achieved can really be achieved. Secondary information was collected from various sources. Several countries and organizations have committed themselves to the following eight development goals: (1) eradicate extreme poverty; (2) achieve universal primary education; (3) promote gender equality and empower women; (4) reduce child mortality; (5) improve maternal health; (6) combat HIV/AIDS, malaria and other diseases; (7) ensure environmental sustainability; and (8) develop a global partnership for development. National development is dependent on many factors; therefore, different countries across the world have adopted the MDGs as means of alleviating many of the social ills hindering progress and development. Based on different sources, Swaziland is on track with its MDGs, and there is no doubt that Swaziland will continue to work hard to these ends. It has been argued that there has been progress made that has resulted in significant changes to people’s lives, but the question that has to be asked is how long these achievements can realistically last. A reduction of the rate of child mortality, maternal mortality and HIV/AIDS in Swaziland are needed.Item Control of airborne microbes in a poultry setting using Dioxy MP 14(FACTA-FUNDACIO ARNCO CIENCIA TECNOLOGIA AVICOLAS, 2015) Mbamalu, O; Uebel, R; Meki, BIn this study, Dioxy MP 14, a locally developed form of chlorine dioxide, was tested in a commercial chicken pen to determine its effectiveness as an airborne environmental sanitizing agent. The biocide was introduced via an overhead misting system with a variable dosing pump. The extent of airborne microbial control was determined with settle plates. Performance and mortality rate of the chickens in the experimental pen was compared to that in the control pen. Results show a decrease in airborne microbial load and a significantly higher egg productivity rate at a 5% level in the treated pen. However, no significant difference in mortality rates between the two pens was observed.Item Tackling sport-related concussion: Effectiveness of lowering the maximum legal height of the tackle in amateur male rugby - A cross-sectional analytical study(BMJ Publishing Group, 2023) van Tonder, Riaan; Surmon, Sean; Starling, Lindsay; Viviers, Pierre; Kraak, WilburObjective Rugby union ( € rugby') is popular globally, with most of its participants being amateur. Concern regarding sport-related concussion (SRC) sustained during rugby is increasing. SRC occurs most frequently in the tackle, yet few interventions have aimed to mitigate this risk factor. This study investigated the influence of a lowered legal tackle height on SRC incidence in amateur rugby. Design Cross-sectional analytical study: 2018 (control - standard tackle height) and 2019 (intervention - lowered legal tackle height) seasons. Setting South African collegiate student rugby competition. Participants Between 800 and 900 male amateur student players (age: 20±1.6 years) in each year. Intervention Maximum legal tackle height lowered from line of the shoulder on the ball carrier to the line of the armpit. Outcome measures Number of overall (medical attention) and time-loss (≥1 day lost) injuries, head injuries and SRCs in 2018 and 2019 (dependent variables); events associated with injury incidents (independent variables). Results There was no statistically significant difference in incidences of time-loss injuries (IRR: 0.79; 95% CI: 0.6 to 1.1; p=0.13), head injuries (IRR: 0.83; 95% CI: 0.5 to 1.3; p=0.42) and SRC (IRR: 0.69; 95% CI: 0.4 to 1.2; p=0.20). In 2018 and 2019, most time-loss head injuries (57%, n=43) and SRCs (55%, n=26) occurred during the tackle. Conclusions Despite a trend towards reducing injuries, head injuries and SRC, lowering maximum legal tackle height to armpit level did not change SRC incidence in this amateur male rugby cohort. Most time-loss head injuries and SRCs occurred during the tackle. Further tackle-related interventions to reduce SRC incidence require investigation.