Epidemiological Design Research Articles

Ownership and Use of Insecticide Treated Nets in Selected Rural Communities of Oyo State, Nigeria: Implication for Policy Action

Introduction: Insecticide Treated Net (ITN) coverage and use remain low in Sub-Sahara Africa. The study assessed factors associated with ITN use in the rural settings of Nigeria. Methodology: Descriptive epidemiological design was employed and multi-stage sampling technique used to select 381 consenting participants in four rural communities of Oyo State, Nigeria. Interviewer-administered, semi-structured questionnaire was used for data collection and analyses done using SPSS; bi-variate analyses were done using chi-square test and binary-logistic regression was used to identify factors that were significantly associated with ITN use. Level of statistical significance was set at p<0.05. Result: The mean age of the respondents was 30±8 years. While 90.1% of the participants possessed ITNs, only 69.3% of them slept under the nets a night before the survey. Respondents who were less than 19 years of age had significantly lesser odds of ITN use compared to older women ((OR; 0.87, CI; 0.82-0.93). Also, women with no formal education had significantly lesser odds of ITN use compared to those with tertiary education (OR; 0.14, CI; 0.02-0.73). Respondents whose households’ monthly income was more than $64 had significantly higher odds of ITN use compared to households earning less (OR; 6.94, CI; 2.76-17.42). Pregnant women were ten times more likely to use ITN compared to non-pregnant participants (OR; 9.84, CI; 1.03-93.88). Conclusion: There is urgent need for more awareness creation on benefits of ITN use particularly among teenage mothers in Nigeria.

Depression after Stroke in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.

Objective We aimed to conduct a systematic review and meta-analysis of prevalence and characteristics of poststroke depression (PSD) in sub-Saharan Africa (SSA). Methods We searched Medline, PsycINFO, and African Journals OnLine using keywords for stroke and depression and the .mp. operator for all 54 SSA countries/regions. Further information was retrieved through a manual search of references from relevant published and unpublished articles. We included only peer-reviewed original studies with epidemiological or experimental designs, conducted random-effect meta-analysis, and identified the most commonly associated factors by weight (inverse of variance method). Results Seventeen studies, comprising 1483 stroke survivors, met the criteria for syntheses. The pooled frequency of clinically diagnosed PSD was 31% (95% CI = 26%–36%), versus 13.9% in healthy control pairs. Prevalence did not vary much across healthcare settings but was affected by methods of depression ascertainment. PSD was significantly associated with low education, cognitive impairment, physical disability, poor quality of life, and divorced marital status. Conclusion Almost 1 in 3 individuals with stroke in SSA has clinical depression. Despite limitations around quality of identified studies, results of the present systematic review overlap with findings in the global literature and highlight useful targets for the design and trial of tailored intervention for PSD in SSA.

T57 - Khat abuse as risk factor for development of psychotic symptoms in trauma patients. A feasibility study for further genetico-epidemiological studies in the GGFRC, ethiopia

Background The Jimma University in southwestern Ethiopia has a unique health and demographic surveillance system called „Gilgel Gibe Field Research Center” (GGFRC) with a catchment area of about 50.000 people. In this setting, we studied the effect of khat use as risk factor for the development and the stability of psychotic symptoms among young men in the community. Our aim was to validate pilot data by testing the hypothesis, whether objective biological data on khat abuse are related in a meaningful way to behavioral self-reports of study participants and psychiatric symptom presentation assessed by trained interviewers. We assumed that khat alkaloids in urine samples of respondents are related to a higher probability of psychotic symptom presentation, especially in the subgroup with high trauma load. Furthermore, we wanted to demonstrate the reliability and validity of research methods that are necessary for future genetic epidemiological studies, i.e. the validity and reliability of pharmacological screening tests as well as assessments performed by trained local interviewers. Methods In this prospective study, trained local interviewers screened a representative cohort of young men twice within a period of nine months (T1: dry season, N=852, T3: rainy season, N=693) to determine the presence and stability of distinct psychiatric symptoms (CIDI) and to assess traumatic experiences (LEC-5). As part of the screening, urine samples were collected and analyzed for khat alkaloids by immunoassay tests for amphetamine. In a clinical validation interview (T2, N=126) mental health specialist reassessed the psychiatric symptom presentation (BPRS) in a randomly selected subgroup of 126 individuals of those persons who had been screened at T1. The validation study took also urine of this subgroup in order to validate the urine screening by a more extensive analysis of khat alkaloids (HPLC). Results Our results on the association between biological objective data and information on psychiatric symptoms assessed by interviews were related in a meaningful way: The proportion of khat-related psychotic symptoms was highest among respondents with positive khat tests and with high trauma load. This tendency was strongest during rainy season (T3) where the market availability and the use of khat was higher (Chi2 = 14.800, df 1, p Discussion By showing these meaningful variations, this pilot study suggest that important theories on the development of psychosis can be further studied in epidemiological and longitudinal designs among khat users. Our project can be seen as a pilot and feasibility study to prepare a comprehensive population-based genetico-epidemiological study on various gene-environment interactions that should be carried out in the very next future. The infrastructure of GGFRC offers us a unique opportunity to build collectives of multiple-thousand people in a shortest period of time and to perform genetic studies as they have not yet been taken in Africa in this form so far. The population is ideally suited to study the impact of polygenic risk profiles of various psychiatric disorders on behavioral traits and their interaction with environment.

Unexplained haemorrhagic fever in Rural Ethiopia.

This case study was written based on events of an outbreak investigation of an unfamiliar disease in Ethiopia during October–December 2012. Ethiopia did not have reports of similar cases in the 50 years prior to this outbreak. In this case study, we recapitulate and analyse this outbreak investigation based on data gathered from the community, health facility, and laboratory systems. It can be used to teach: 1) the outbreak investigation process; 2) selection of appropriate epidemiological design for the investigation process, 3) basic statistical analysis of surveillance data, and 4) principals of disease control. The target audiences for this case study are officials working in public health and public health trainees. It will take at most 3.5 hours to complete this case study. At the end of the case study, participants should be able to apply the principals of outbreak investigation and use surveillance data to respond to an outbreak in their country-specific context.

Epidemiological Methods.

This chapter provides an overview of the most common epidemiological designs used in clinical studies to better understand innate anti-viral immunity. Studies to assess risk factors as well as interventions are described.

Does case misclassification threaten the validity of studies investigating the relationship between neck manipulation and vertebral artery dissection stroke? No.

BackgroundThe purported relationship between cervical manipulative therapy (CMT) and stroke related to vertebral artery dissection (VAD) has been debated for several decades. A large number of publications, from case reports to case–control studies, have investigated this relationship. A recent article suggested that case misclassification in the case–control studies on this topic resulted in biased odds ratios in those studies.DiscussionGiven its rarity, the best epidemiologic research design for investigating the relationship between CMT and VAD is the case–control study. The addition of a case-crossover aspect further strengthens the scientific rigor of such studies by reducing bias. The most recent studies investigating the relationship between CMT and VAD indicate that the relationship is not causal. In fact, a comparable relationship between vertebral artery-related stroke and visits to a primary care physician has been observed. The statistical association between visits to chiropractors and VAD can best be explained as resulting from a patient with early manifestation of VAD (neck pain with or without headache) seeking the services of a chiropractor for relief of this pain. Sometime after the visit the patient experiences VAD-related stroke that would have occurred regardless of the care received.This explanation has been challenged by a recent article putting forth the argument that case misclassification is likely to have biased the odds ratios of the case–control studies that have investigated the association between CMT and vertebral artery related stroke. The challenge particularly focused on one of the case–control studies, which had concluded that the association between CMT and vertebral artery related stroke was not causal.It was suggested by the authors of the recent article that misclassification led to an underestimation of risk. We argue that the information presented in that article does not support the authors’ claim for a variety of reasons, including the fact that the assumptions upon which their analysis is based lack substantiation and the fact that any possible misclassification would not have changed the conclusion of the study in question.ConclusionCurrent evidence does not support the notion that misclassification threatens the validity of recent case–control studies investigating the relationship between CMT and VAD. Hence, the recent re-analysis cannot refute the conclusion from previous studies that CMT is not a cause of VAD.

The Intracranial Distribution of Gliomas in Relation to Exposure From Mobile Phones: Analyses From the INTERPHONE Study.

When investigating the association between brain tumors and use of mobile telephones, accurate data on tumor position are essential, due to the highly localized absorption of energy in the human brain from the radio-frequency fields emitted. We used a point process model to investigate this association using information that included tumor localization data from the INTERPHONE Study (Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden, and the United Kingdom). Our main analysis included 792 regular mobile phone users diagnosed with a glioma between 2000 and 2004. Similar to earlier results, we found a statistically significant association between the intracranial distribution of gliomas and the self-reported location of the phone. When we accounted for the preferred side of the head not being exclusively used for all mobile phone calls, the results were similar. The association was independent of the cumulative call time and cumulative number of calls. However, our model used reported side of mobile phone use, which is potentially influenced by recall bias. The point process method provides an alternative to previously used epidemiologic research designs when one is including localization in the investigation of brain tumors and mobile phone use.

Characteristics of Biostatistics, Epidemiology, and Research Design Programs in Institutions With Clinical and Translational Science Awards.

To learn the size, composition, and scholarly output of biostatistics, epidemiology, and research design (BERD) units in U.S. academic health centers (AHCs). Each year for four years, the authors surveyed all BERD units in U.S. AHCs that were members of the Clinical and Translational Science Award (CTSA) Consortium. In 2010, 46 BERD units were surveyed; in 2011, 55; in 2012, 60; and in 2013, 61. Response rates to the 2010, 2011, 2012, and 2013 surveys were 93.5%, 98.2%, 98.3%, and 86.9%, respectively. Overall, the size of BERD units ranged from 3 to 86 individuals. The median FTE in BERD units remained similar and ranged from 3.0 to 3.5 FTEs over the years. BERD units reported more availability of doctoral-level biostatisticians than doctoral-level epidemiologists. In 2011, 2012, and 2013, more than a third of BERD units provided consulting support on 101 to 200 projects. A majority of BERD units reported that between 25% and 75% (in 2011) and 31% to 70% (in 2012) of their consulting was to junior investigators. More than two-thirds of BERD units reported their contributions to the submission of 20 or more non-BERD grant or contract applications annually. Nearly half of BERD units reported 1 to 10 manuscripts submitted annually with a BERD practitioner as the first or corresponding author. The findings regarding BERD units provide a benchmark against which to compare BERD resources and may be particularly useful for institutions planning to develop new units to support programs such as the CTSA.

Natural history of diseases: Statistical designs and issues.

Understanding the natural history of a disease is an important prerequisite for designing studies that assess the impact of interventions, both chemotherapeutic and environmental, on the initiation and expression of the condition. Identification of biomarkers that mark disease progression may provide important indicators for drug targets and surrogate outcomes for clinical trials. However, collecting and visualizing data on natural history is challenging, in part, because disease processes are complex and evolve in different chronological periods for different subjects. Various epidemiological designs are used to elucidate components of the natural history process. We briefly discuss statistical issues, limitations, and challenges associated with various epidemiological designs.

Characterization of Viral Populations by Using Circular Sequencing.

With the enormous sizes viral populations reach, many variants are at too low a frequency to be detected by conventional next-generation sequencing (NGS) methods. Circular sequencing (CirSeq) is a method by which the error rate of next-generation sequencing is decreased so that even low-frequency viral variants can be accurately detected. The ability to visualize almost the entire genetic makeup of a viral swarm has implications for epidemiology, viral evolution, and vaccine design. Here we discuss experimental planning, analysis, and recent insights using CirSeq.

The cytokinesis-block micronucleus (CBMN) assay in human populations exposed to styrene: A systematic review and meta-analysis.

Styrene is a building-block of several compounds used in a wide array of materials and products. The most important human exposure to this substance occurs in industrial settings, especially among reinforced-plastics industry workers. The effect of occupational exposure to styrene on cytogenetics biomarkers has been previously reviewed with positive association observed for chromosomal aberrations, and inconclusive data for the micronucleus assay. Some limitations were noted in those studies, including inadequate exposure assessment and poor epidemiological design. Furthermore, in earlier studies micronuclei frequency was measured with protocols not as reliable as cytokinesis-block micronucleus (CBMN) assay. Aim of the present systematic review and meta-analysis is to investigate genomic instability and DNA damage as measured by the CBMN assay in lymphocytes of subjects exposed to styrene. A total of 11 studies published between 2004 and 2012 were included in the meta-analysis encompassing 479 styrene-exposed workers and 510 controls. The quality of each study was estimated by a quality scoring system which ranked studies according to the consideration of major confounders, exposure characterization, and technical parameters. An overall increase of micronuclei frequencies was found in styrene-exposure workers when compared to referents (meta-MR 1.34; 95% CI 1.18-1.52), with significant increases achieved in six individual studies. The consistency of results in individual studies, the independence of this result from major confounding factors and from the quality of the study strengthens the reliability of risk estimates and supports the use of the CBMN assay in monitoring genetic risk in styrene workers.

A Study to Ascertain the Adequacy of Observance of Standard Precautions in Acute Medical and Surgical Wards of a Large Teaching Hospital

The present study was a cross-sectional analytic epidemiological design to assess the frequency of observance of universal precautions in acute care wards of a large teaching hospital and to assess the epidemiological determinants of such observance. A total population of medical officers, nurses, paramedical and ancillary workers working in acute medical and surgical wards was studied using direct observations recorded on a pre-tested, structured format. The study revealed that hand washing was more frequently practiced by medical officers and ancillary staff (68–93 per cent) as compared to nurses and paramedical staff (38–58 per cent) ( p &lt; 0.01). A significantly higher proportion of medical officers in medical wards (93 per cent) and nurses (63.3 per cent) and ancillary workers in surgical ward (89 per cent) were practicing hand washing ( p &lt; 0.01). The practice of usage of gloves was significantly more frequent among medical officers and ancillary workers (72–100 per cent), while it was quite inadequate among nurses and paramedical staff (28–36 per cent; p &lt; 0.001). However, the use of gloves was significantly better among nurses in the surgical ward and paramedical in the medical ward ( p &lt; 0.05). A linear trend analysis of the use of protective clothing revealed that the odds of nurses adequately using the same were much lower, while those of ancillary workers were much higher as compared to medical officers, the trend being highly significant in both types of wards ( p &lt;0.001). The study reveals a definite need for stepping up educational and motivational methods for observance of universal precautions by health-care workers in large teaching hospitals. In particular, nurses and paramedical workers have been identified as high-risk groups, needing concerted efforts for observing these precautions.

Addressing epidemiological and public health analytic challenges in outcome and impact research: a commentary on 'Prechewing Infant Food, Consumption of Sweets and Dairy and Not Breastfeeding are Associated with Increased Diarrhea Risk of Ten Month Old Infants'.

Based on a paper by Conkle et al 2016, in which the authors use a descriptive epidemiological design to examine the relationship of premastication and other dietary behavioral variables to childhood diarrhea in the US, we address larger issues of "plausible causality" and the challenges involved in moving from epidemiological studies to public health policy. Drawing on examples from breastfeeding research and water, sanitation and hygiene (WASH) research, we discuss the following propositions: 1. Effective outcome analyses require simultaneous investigation of different, even contradictory, pathways; 2. Outcome versus impact assessments require different analytic procedures including context analysis; 3. Impact analysis requires understanding the trade-offs between detrimental and beneficial outcomes in relation to potential interventions; 4. No estimates exist for the likely detrimental and beneficial impacts of banning premastication, much less for their trade-offs.

Learning for improvement

Learning for improvement

Respiratory health outcomes and air pollution in the Eastern Mediterranean Region: a systematic review.

Exposure to air pollution can cause detrimental health and be an economic burden. With newly developed equipment, monitoring of different air pollutants, identifying the sources, types of air pollutants and their corresponding concentrations, and applying mitigation intervention techniques became a crucial step in public health protection. Countries in the Eastern Mediterranean Region (EMR) are highly exposed to dust storms, have high levels of particulate matter (PM) concentrations, and have a unique climatic as well as topographic and socio-economic structure. This is the first study conducted to systemically and qualitatively assess the health impacts of air pollution in the EMR, identify susceptible populations, and ascertain research and knowledge gaps in the literature to better inform decisions by policy makers. We screened relevant papers and reports published between 2000 and 2014 in research databases. A total of 36 published studies met the inclusion criteria. A variety of indoor and outdoor exposures associated with various acute and chronic respiratory health outcomes were included. Respiratory health outcomes ranged in severity, from allergies and general respiratory complaints to lung cancer and mortality. Several adverse health outcomes were positively associated with various indoor/outdoor air pollutants throughout the EMR. However, epidemiological literature concerning the EMR is limited to a few studies in a few countries. More research is needed to elucidate the health outcomes of air pollution. Standardized reliable assessments on the national level for various air pollutants in different regions should be implemented and made publically available for researchers to utilize in their research. Moreover, advancing and utilizing more sound epidemiological designs and studies on the effect of air pollution on the respiratory health outcomes is needed to portray the actual situation in the region.

Antidepressants and Driving in Older Adults: A Systematic Review.

With an increasing number of older drivers who are prescribed antidepressants, the potential consequences of antidepressant use on driving skills in an aging population are becoming a pressing issue. We conducted a systematic review using MEDLINE, targeting articles specifically pertaining to antidepressants and driving in a population or subgroup of older adults (≥ 55 years of age). The search yielded 267 references, nine of which pertained to the effects of antidepressants on driving in older adults. The single experimental study found imipramine to have detrimental effects on highway driving, whereas nefazodone did not. Seven of eight population-based studies reported a significant increased risk of involvement in a collision associated with antidepressant use. Although the studies indicated a negative effect of antidepressants on driving, the epidemiological designs cannot exclude the possibility that the underlying illness, generally major depression, is the culprit.

Learning to perform research in the degree of medicine: analysis and evaluation of the student ratings of the final degree dissertation.

The Bologna Plan applied to the Medicine Degree in Spain has included a final degree dissertation into the coursework. In this manuscript, we analyzed the validity of a rubric and the grading criteria used to assess the students skills in research and their critical thinking. A total of 62 final degree dissertations were evaluated. Each student was supervised by a clinical or epidemiologist researcher. Each dissertation was rated by three academic assistants using a 10-item rubric. The validity of the scores and the differences in the severity of the examiners were analyzed with a multi-faceted Rasch model, which allowed examining severity within evaluators, ability of the students and difficulty of items. 62 final dissertation were evaluated with a total of 186 rubrics. 58% of the students had higher ability than the severity of the evaluators and the difficulty of the items of the evaluation rubric. No significant differences were observed within the severity of the professors, neither within the final scores. The most difficult item for students was selection of epidemiological design. This study showed that the methodology proposed to evaluate the final degree dissertation is effective to assess the skills of conducting research and critical thinking in medicine students.

Epidemiological characteristics of rabies in Zambia: A retrospective study (2004–2013)

BackgroundHuman and animal rabies have been known to be present in Zambia since the early 1900s. However, systematic reporting, analysis, and dissemination have remained limited. This study aims to quantify trends and patterns in confirmed rabies cases and human dog bites based on reported hospital and laboratory data in Zambia, for the period 2004–2013. We further explore the space–time evolution of risk of confirmed rabies cases and dog bites. MethodData on human dog bites, confirmed rabies cases by province for the period 2004–2013, and on rabid dogs in the period 2005–2012 were analyzed. We calculated the incidence rates, by year and province, and modeled the spatial variability in risk at province level using Poisson spatial regression. ResultsA total of 14,818 dog bites occurred in all provinces for 2004–2013. The rate of dog bites ranged from 0.01 to 9.18 per 10,000 population. The incidence rate of rabid dogs varied from 2.4 to 17.5 per 10,000 dog population. Over the years, the risk of dog bites varied. The highest risks were at Western province (RR=14.91, 95% CI: 9.08–34.09) in 2004 and Lusaka province from 2009 to 2013. The risk of rabies in dogs increased in Central province (RR=1.79, 95 CI: 1.11–2.74). ConclusionThis study reveals increasing trends in reported dog bites and rabies. The increase could be a case of improved reporting due to change in health policies or indeed high incidence necessitated by change in ecosystem. Moreover, the risk of dog bites and confirmed rabies seem to be established in selected provinces. A more detailed epidemiological design is warranted to establish such increases in risk.

Genetic Epidemiology and Public Health: The Evolution From Theory to Technology.

Genetic epidemiology represents a hybrid of epidemiologic designs and statistical models that explicitly consider both genetic and environmental risk factors for disease. It is a relatively new field in public health; the term was first coined only 35 years ago. In this short time, the field has been through a major evolution, changing from a field driven by theory, without the technology for genetic measurement or computational capacity to apply much of the designs and methods developed, to a field driven by rapidly expanding technology in genomic measurement and computational analyses while epidemiologic theory struggles to keep up. In this commentary, we describe 4 different eras of genetic epidemiology, spanning this evolution from theory to technology, what we have learned, what we have added to the broader field of public health, and what remains to be done.

Epidemiological Study of Occupational Injuries Among Farmers in Iran

Agriculture is among the top three most dangerous occupations in the world. Farm injuries are, therefore, more prevalent in it as compared to other work-related injuries. In Iran, outdated farm machineries coupled with unsafe working conditions have exposed farmers to a wide variety of job injuries. However, research on farm injury types and sources of injuries are scarce. Therefore, the purpose of this epidemiological research design was to identify the most prevalent farm injuries in Kermanshah townships in Iran. Data were collected from a census of farmers who were injured during farm practices (N=90). A researcher made questionnaire was used to collect data. The validity and reliability of research instrument was verified using panel of experts and alpha coefficient respectively. Results revealed that the most prevalent job injuries among farmers were: amputations, fractures, cuts and bruises, and muscle-skeletal defects. Moreover, tractors, water pumps, carrying heavy objects, and heavy workloads played major role in farm injuries. Results of this study have implications for agricultural extension service as well as professional health services in Kermanshah province. Extension agents can use the results in adult education programs in order to reduce injuries among farmers.