Epidemiological study designs and principles of data analysis: A conceptually integrated suite of methods and techniques

2016 ◽  
Author(s):  
Raj S. Bhopal
Keyword(s):  
Risk Factors ◽  
Disease Incidence ◽  
Case Series ◽  
Epidemiological Studies ◽  
Cross Sectional Study ◽  
Natural Experiments ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Common Goals ◽  
Study Designs

Epidemiological studies are unified by their common goals and by their basis in defined populations. The case series (or register-based study) includes examination of trends in deaths, cancers, notifiable diseases, and hospitalizations. Case–control studies are analysed by comparing the exposure to risk factors in cases to those in controls. In a population studied at a specific time and place (a cross-sectional study), measurements can be made of disease, the factors which may cause disease, or both simultaneously. Cohort studies produce data on disease incidence and are especially good on associations between risk factors and disease outcomes. Trials compare treated and untreated populations and are used, primarily, for information on effectiveness of health interventions. Natural experiments, including Mendelian randomization studies, may provide causal evidence. The principles for the analysis of all studies are similar. The design and interpretation should be in the context of traditional, systematic, and meta-analytic reviews.

Predictors of Psychiatric Morbidity in Cancer Patients

1994 ◽  
Vol 165 (5) ◽  
pp. 593-598 ◽  
Author(s):  
Judy Harrison ◽  
Peter Maguire
Keyword(s):  
Risk Factors ◽  
Cancer Patients ◽  
Psychiatric Morbidity ◽  
Significant Proportion ◽  
Cross Sectional Study ◽  
Future Research ◽  
Cross Sectional ◽  
Appropriate Treatment ◽  
Study Designs ◽  
Patients Experience

BackgroundA significant proportion of cancer patients experience psychiatric morbidity in association with diagnosis and treatment. If this morbidity is to be reduced, a better understanding is needed of the factors which influence adjustment to cancer.MethodA review of the literature was carried out to explore those factors associated with poor psychological adjustment to cancer. These are described under four headings: characteristics of the patient; disease and treatment variables; the interaction between patient and illness; and environmental factors.ResultsA number of risk factors for psychiatric morbidity can be identified from each of the four areas. Methodological limitations are highlighted, in particular the preponderance of cross-sectional study designs.ConclusionsIncreased awareness of the risk factors for psychiatric morbidity should lead to earlier detection and more appropriate treatment. Future research should focus on those risk factors which are potentially modifiable.

scholarly journals Risk Factors for Age-Related Maculopathy

2009 ◽  
Vol 2009 ◽  
pp. 1-39 ◽  
Author(s):  
Paul P. Connell ◽  
Pearse A. Keane ◽  
Evelyn C. O'Neill ◽  
Rasha W. Altaie ◽  
Edward Loane ◽  
...  
Keyword(s):  
Risk Factors ◽  
Epidemiologic Study ◽  
Case Series ◽  
The Elderly ◽  
Factor H ◽  
Environment Interaction ◽  
Complement Factor ◽  
Case Control Studies ◽  
Cross Sectional ◽  
Age Related

Age-related maculopathy (ARM) is the leading cause of blindness in the elderly. Although beneficial therapeutic strategies have recently begun to emerge, much remains unclear regarding the etiopathogenesis of this disorder. Epidemiologic studies have enhanced our understanding of ARM, but the data, often conflicting, has led to difficulties with drawing firm conclusions with respect to risk for this condition. As a consequence, we saw a need to assimilate the published findings with respect to risk factors for ARM, through a review of the literature appraising results from published cross-sectional studies, prospective cohort studies, case series, and case control studies investigating risk for this condition. Our review shows that, to date, and across a spectrum of epidemiologic study designs, only age, cigarette smoking, and family history of ARM have been consistently demonstrated to represent risk for this condition. In addition, genetic studies have recently implicated many genes in the pathogenesis of age-related maculopathy, including Complement Factor H, PLEKHA 1, and LOC387715/HTRA1, demonstrating that environmental and genetic factors are important for the development of ARM suggesting that gene-environment interaction plays an important role in the pathogenesis of this condition.

scholarly journals Prevalence of Infections Bronchities Virus at Four Selected Districts (Damot Gale, Sodozuri, Humbo and Kindokoy) In Southern Nations, Nationalities and Peoples

2021 ◽  
pp. 1-6
Author(s):  
Abebe Garooma Gichile ◽  
Keyword(s):  
Risk Factors ◽  
Simple Random Sampling ◽  
Epidemiological Studies ◽  
Cross Sectional Study ◽  
Sampling Procedure ◽  
Economic Losses ◽  
Poultry Production ◽  
Chi Square ◽  
Cross Sectional ◽  
Infectious Bronchitis

Infectious bronchitis is an important virial disease affecting poultry production which causes significant economic losses. A cross-sectional study was carried out from November 2019 to January 2020. To estimating the prevalence of infectious bronchitis and determines the risk factors. A total 420 poultry were by a simple random sampling procedure. Data was analyzed using STATA version 11. Chi square test and logistic regression analysis were used to determine the association between prevalence of infectious bronchitis and potential risk factors. From the total 420 poultry examined for infectious bronchitis were found positive. There was significance difference between the risk factors and bronchitis infections. More infectious bronchitis infected poultry were found in kindokoy 90.4%, odd ratio: 0.3 Confidence Interval :0.1-0.7, p = 0.00 than humbo, sodozuri and damotgale. There was high prevalence of infectious bronchitis in gerater than 6 months than less than 3 months and between 3 and 6-month age of poultry. The presence of infectious bronchitis in poultry production might entail morbidity and mortality. Therefore, further detailed molecular epidemiological studies are warranted. Good hygienic and husbandry practices are essential to limit the spread of infection

Conducting epidemiological studies in health protection

2016 ◽  
Author(s):  
Sam Ghebrehewet ◽  
Paul Cleary ◽  
Merav Kliner ◽  
Ewan Wilkinson
Keyword(s):  
Case Reports ◽  
Real Life ◽  
Case Series ◽  
Epidemiological Studies ◽  
Health Protection ◽  
Sample Size Determination ◽  
Cross Sectional ◽  
Randomized Controlled ◽  
Different Types ◽  
Study Designs

This chapter describes the different types of epidemiological studies that are used in health protection investigations. These include descriptive studies such as case reports, case series, cross-sectional studies, and analytical studies, particularly case-control and cohort studies. It provides a number of real-life examples illustrating these different types of investigation and their application in health protection practice. It also gives guidance on the type of study to use in different incidents or outbreaks, and on sample size determination. The limitations of the different study designs are described. The particular requirements of randomized controlled trials and systematic reviews, and their role in health protection are described. The roles of qualitative and operational studies are also outlined.

scholarly journals Rhinoconjunctivitis among Adolescents in Kuwait and Associated Risk Factors: A Cross-Sectional Study

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Ali H. Ziyab ◽  
Yaser M. Ali
Keyword(s):  
Risk Factors ◽  
Variance Estimation ◽  
Public Health Problem ◽  
Clinical History ◽  
Epidemiological Studies ◽  
Cross Sectional Study ◽  
Sectional Study ◽  
Cross Sectional ◽  
Parental History ◽  
Major Illness

Rhinoconjunctivitis is a public health problem that causes major illness and disability worldwide. Epidemiological studies intended to determine the burden of rhinoconjunctivitis in Kuwait are limited. Hence, this study sought to estimate the prevalence of rhinoconjunctivitis among adolescents in Kuwait and explore its association with different risk factors. Schoolchildren aged 11–14 years (n = 3,864) were enrolled in a cross-sectional study. Parents completed questionnaires regarding their children’s clinical history and symptoms of rhinoconjunctivitis and relevant exposures. Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (aPRs) and 95% confidence intervals (CIs) were estimated. The 12-month (current) prevalence estimates of rhinitis, rhinoconjunctivitis, and severe rhinoconjunctivitis were 28.6% (1,040/3,643), 13.5% (497/3,689), and 1.2% (44/3,689), respectively. The prevalence of current rhinoconjunctivitis symptoms was higher in boys compared to girls (aPR = 1.19, 95% CI: 1.01–1.41). Parental history of rhinitis and asthma showed positive associations with rhinoconjunctivitis in offspring. Trend analyses showed that rhinoconjunctivitis prevalence decreased with increasing numbers of total siblings (aPR = 0.92, Ptrend<0.001) and older siblings (aPR = 0.90, Ptrend<0.001). Rhinoconjunctivitis is common among adolescents in Kuwait and its epidemiology is similar to that found in western countries.

Leishmania infantum: illness, transmission profile and risk factors for asymptomatic infection in an endemic metropolis in Brazil

Parasitology ◽  
2016 ◽  
Vol 144 (4) ◽  
pp. 546-556 ◽  
Author(s):  
LETÍCIA HELENA DOS SANTOS MARQUES ◽  
IARA CAIXETA MARQUES DA ROCHA ◽  
ILKA AFONSO REIS ◽  
GISELE MACEDO RODRIGUES DA CUNHA ◽  
EDWARD OLIVEIRA ◽  
...  
Keyword(s):  
Risk Factors ◽  
Leishmania Infantum ◽  
Disease Incidence ◽  
Significant Proportion ◽  
Cross Sectional Study ◽  
Asymptomatic Infection ◽  
Infection Prevalence ◽  
Prevalence Rates ◽  
Cross Sectional ◽  
Relative Risks

SUMMARYTo evaluate the distribution of asymptomatic infection by Leishmania infantum in a metropolis in Brazil with different relative risks (RRs) for disease and risk factors associated with the infection, an ecological study was conducted using a Bayesian approach to estimate the RR of human visceral leishmaniasis (HVL) based on cases between 2008 and 2011. The areas were categorized and selected according to disease incidence: low (area-1), medium (area-2) and high (area-3). Cross-sectional study enrolling 935 children was used to estimate the prevalence of infection by L. infantum. Volunteers from these three areas were tested for L. infantum infection by ELISA (rK39 and soluble antigens). Infection prevalence rates were estimated and compared with the RR of disease. Multilevel logistic regression model evaluated the relationship between infection and the analysed variables. The RR of HVL was distributed heterogeneously in the municipality. The infection prevalence rates were: 34·9% in area-1; 29·3% in area-2; and 33·6% in area-3, with no significant differences between these areas. The variables ‘Presence of backyards in the neighbourhood’ and ‘Younger children’ were associated with L. infantum infection. We conclude that infection by L. infantum affects a significant proportion of the infant population regardless of the RR of disease.

scholarly journals Assessment of Risk Factors in Patients with Chronic Hepatitis B

2021 ◽  
Author(s):  
Sorush Niknamian
Keyword(s):  
Risk Factors ◽  
Chronic Hepatitis ◽  
Hepatitis B ◽  
Chronic Hepatitis B ◽  
Meta Analysis ◽  
Epidemiological Studies ◽  
Cross Sectional Study ◽  
Cross Sectional ◽  
Cultural Themes ◽  
History Of

Background: Hepatitis B virus infection and its complications are major health problems. The aim of this study were to investigate risk factors in patients with chronic hepatitis B. Methods: This cross-sectional study was performed on 174 patients with chronic hepatitis B who referred to the Shahid Mohammadi hospital in the city of Bandar Abbas, Iran. Information was collected through a questionnaire. Results: 174 persons (97 males, 77 females) with a mean age of 42.96 years. There was no significant relationship between the risk of having disease with gender, age, weight, height, waist circumference, hip circumference, BMI and WHR (P&gt; 0.05). The frequency of exposure to risk factors are as follows: such as history of hairdressers, vaccination, contact with suspected HBV persons, Family history of HBV positive in patients had higher prevalence than other groups. Conclusion: It seems to be more important to pay attention to lifestyles, jobs, and cultural themes of Iranian people that predispose people to risk factors so as to implement measures to control HBV spread. Also, awareness and social-health education in order to avoid unprotected sexual contact with an infected partner can be highly effective according to the high levels of hepatitis B infection among married persons. Despite existence of a long list of risk factors, various epidemiological studies with alternative methodologies along with meta-analysis of risk factors in each separate area seems to be helpful in collecting information about transmission.

scholarly journals Prevalence and Risk Factors of Toxoplasma Gondii and Leishmania Spp. Infections in Apparently Healthy Dogs in West Shewa Zone, Oromia, Ethiopia

2021 ◽  
Author(s):  
Endrias Zewdu Gebremedhin ◽  
Edilu Jorga Serba ◽  
Getachew Kebebew Tola ◽  
Solomon Shiferaw Endalew ◽  
Lencho Megersa Marami ◽  
...  
Keyword(s):  
Risk Factors ◽  
Toxoplasma Gondii ◽  
Epidemiological Studies ◽  
Domestic Animals ◽  
Cross Sectional Study ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cross Sectional ◽  
Leishmania Spp ◽  
Potential Risk Factors ◽  
Educational Campaigns

Abstract Background In urban settings, the presence of a high density of human population and contacts with domestic and or stray animals such as dogs and cats can be risk factors for the transmission of zoonotic diseases. Toxoplasma gondii (T. gondii) and Leishmania spp. are zoonotic protozoon parasites with great health burdens worldwide. Methods A cross-sectional study was used to investigate the antibody prevalence and risk factors of T. gondii and Leishmania spp. infections in 385 randomly selected dogs of Ambo, Bako, and Gojo towns of West Shewa zone, Oromia regional state, Ethiopia. A questionnaire survey was administered to households to collect data on potential risk factors. Dog sera samples were assayed for T. gondii IgG antibodies by using the direct agglutination test while Leishmania spp. specific antibodies were tested using an indirect enzyme-linked immunosorbent assay (ELISA) kit. Logistic regression was used for data analysis. Results An overall 82.86% (95% CI): 78.71–86.49%) and 92.47% (95% CI: 89.36–94.90%) seroprevalence of T. gondii and Leishmania spp. was found respectively. Seropositivity for both T. gondii and Leishmania spp was found in 82.58% of the dogs. None of the investigated factors were associated with Leishmania spp. seropositivity (p > 0.05). Furthermore, altitude, sex, breed, housing, feeding, educational level of head of the household, and the living area of dogs were not significantly associated with T. gondii seropositivity (p > 0.05). The seroprevalence of T. gondii was significantly different between the study towns (p = 0.003). The risk of T. gondii infection was 2.71 times higher in adult dogs than juvenile dogs (p = 0.043). Dogs kept simultaneously with other domestic animals had increased odds of T. gondii seropositivity as compared to those with no other domestic animals (Adjusted Odds ratio: 1.96, p = 0.021). Conclusions The high seropositivity and the concomitant presence of antibodies of T. gondii and Leishmania spp. in dogs suggest the widespread nature of these parasites in the environment and the high potential of transmission to other animals and humans. Further epidemiological studies, isolation and molecular characterization of the parasites, and educational campaigns are suggested.

scholarly journals Seroprevalence and risk factors for hepatitis B and hepatitis C in three large regions of Kazakhstan

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261155
Author(s):  
Alexander Nersesov ◽  
Arnur Gusmanov ◽  
Byron Crape ◽  
Gulnara Junusbekova ◽  
Salim Berkinbayev ◽  
...  
Keyword(s):  
Risk Factors ◽  
Hepatitis C ◽  
Blood Transfusion ◽  
Hepatitis B ◽  
Epidemiological Studies ◽  
Cross Sectional Study ◽  
Cluster Sampling ◽  
Cross Sectional ◽  
History Of ◽  
Comprehensive Programs

Background & aims Kazakhstan has implemented comprehensive programs to reduce the incidence of Hepatitis B and Hepatitis C. This study aims to assess seroprevalence and risk factors for HBsAg and anti-HCV positivity in three large regions of Kazakhstan. Methods A cross-sectional study was conducted in three regions geographically remote from each other. Participants were randomly selected using a two-stage stratified cluster sampling and were surveyed by a questionnaire based on the WHO STEP survey instrument. Blood samples were collected for HBsAg and anti-HCV testing. Results A total of 4,620 participants were enrolled. The seroprevalence was 5.5% (95%CI: 3.6%-8.4%) for HBsAg and 5.1% (95%CI: 3.5%-7.5%) for anti-HCV antibodies. Both were more prevalent in the western and northern regions than in the southern. A history of blood transfusion was significantly associated with anti-HCV presence, with odds ratios (ORs) of 2.10 (95%CI: 1.37–3.21) and was borderline associated with HBsAg 1.39 (95%CI: 0.92–2.10), respectively. Having a family member with viral hepatitis was also borderline associated (2.09 (95%CI: 0.97–4.50)) with anti-HCV positivity. Conclusions This study found a high-intermediate level of endemicity for HBsAg and a high level of endemicity for anti-HCV antibodies in three large regions of Kazakhstan. We found that history of surgery was not associated with HbsAg neither with anti-HCV seropositivity rates. Blood transfusion was associated with anti-HCV seropositivity, however, to investigate effectiveness of the introduced comprehensive preventive measures in health care settings, there is a need to conduct further epidemiological studies.

scholarly journals Prevalence and risk factors of Toxoplasma gondii and Leishmania spp. infections in apparently healthy dogs in west Shewa zone, Oromia, Ethiopia

2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Endrias Zewdu Gebremedhin ◽  
Edilu Jorga Sarba ◽  
Getachew Kebebew Tola ◽  
Solomon Shiferaw Endalew ◽  
Lencho Megersa Marami ◽  
...  
Keyword(s):  
Risk Factors ◽  
Toxoplasma Gondii ◽  
Epidemiological Studies ◽  
Domestic Animals ◽  
Cross Sectional Study ◽  
Enzyme Linked Immunosorbent Assay ◽  
Cross Sectional ◽  
Leishmania Spp ◽  
Potential Risk Factors ◽  
Educational Campaigns

Abstract Background In urban settings, the presence of a high density of the human population and contact with domestic and/or stray animals such as dogs and cats can be risk factors for the transmission of zoonotic protozoa parasites. Toxoplasma gondii (T. gondii) and Leishmania spp. are zoonotic protozoon parasites with significant health burdens worldwide. Methods A cross-sectional study was used to investigate the antibody prevalence and risk factors of T. gondii and Leishmania spp. infections in 385 randomly selected dogs of Ambo, Bako, and Gojo towns of West Shewa Zone, Oromia regional state, Ethiopia. A questionnaire survey was administered to households to collect data on potential risk factors. Dog sera samples were assayed for T. gondii IgG antibodies using the direct agglutination test while Leishmania spp. specific antibodies tested using an indirect enzyme-linked immunosorbent assay (ELISA). Logistic regression was used for data analysis. Results Overall, T. gondii and Leishmania spp. infection seroprevalence was found to be 82.86% (95% confidence interval (CI): 78.71–86.49%) and 92.47% (95% CI: 89.36–94.90%), respectively. Seropositivity for both T. gondii and Leishmania spp. was found in 82.58% of the dogs. None of the investigated factors were associated with Leishmania spp. seropositivity (p > 0.05). The seroprevalence of T. gondii was significantly different among the study towns (p = 0.003). The risk of T. gondii infection was 2.71 times higher in adult dogs than juvenile dogs (p = 0.043). Dogs kept simultaneously with other domestic animals had increased odds of T. gondii seropositivity compared to those with no other domestic animals (Adjusted Odds ratio: 1.96, p = 0.021). However, altitude, sex, breed, housing, feeding, educational level of head of the household, and dog’s living area were not significantly associated with T. gondii seropositivity (p > 0.05). Conclusions The high seropositivity and the simultaneous presence of antibodies of T. gondii and Leishmania spp. in dogs suggest the widespread nature of these parasites in the environment and the high potential of transmission to other animals and humans. Further epidemiological studies, isolation and molecular characterization of the parasites, and educational campaigns are suggested.

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