types of study designs: – cross-sectional, cohort, and randomized controlled studies
Epidemiology is a branch of medicine dealing with the occurrence, prevalence, patterns, and possible control of diseases, among other factors that relate to public health. Epidemiology is essential in public health since epidemiologists can conduct outbreak investigations, survey diseases, and subsequently identify risk factors of various diseases. An epidemiological study can take many forms and occurs in the stages of preparation, finding cases and recording data, data analysis, development of hypotheses, and testing of the hypotheses epidemiologically. This paper will critically review three articles on three types of study designs: – cross-sectional, cohort, and randomized controlled studies.
Background
In a broader sense, epidemiology can be defined as the study of the distribution in terms of subject, location, and time i.e., who, where, and when, determinants and patterns of disease conditions in a population, done through public health research. Epidemiology is vital in public health since the study assists in the identification of risk factors for diseases and the preventive measures that can be taken up against them. Don't use plagiarised sources.Get your custom essay just from $11/page
Public health research occurs in a systematic process discussed hereunder: – Firstly, the problem has to be sufficiently described. This research involves the confirmation of a given problem as a public health issue, which is done through epidemiological study. The next step is the identification of risk factors. This helps to show the group at the highest risk of the health issue. This is followed by exploring the context and identity of determinants. Here, the focus is on describing social or behavioral aspects that lead to the risk factors discussed above, which is essential because most of the public health problems are resultant from human behavior, and research is needed to show why the people behave the way they do. This is followed by the formulation and selection of possible interventions for the problem. After a solution has been identified, the step that follows next is to test the responses, which involves conducting of studies to determine the efficacy and feasibility of the intervention to the recipient. Finally, the effectiveness and effectiveness of public health intervention is assessed. This is done through public health efficacy trials and public health effectiveness trials, done to determine the feasibility of the intervention.
As discussed above, in conducting public health research, various methods can be employed. The first method is the cross-sectional study design. This study deals with the examination of the relationship between the disease, infection, or other such health-related conditions and other variables that are of interest in a population at a point in time. The strengths associated with this study are that firstly, it is relatively quick and easy to conduct since data on the variables are all collected at once. Secondly, through this method, the prevalence of all factors under investigation can be measured, and incidentally, multiple outcomes can be studied. The weaknesses of this study, on the other hand, are that it gives a result on prevalence rather than incidence of diseases and that it is sometimes difficult to determine whether exposure followed outcome or outcome followed exposure. Additionally, it is least suited for studying short-term conditions.
The second method id the cohort study design, which involves having a group of individuals exposed to a putative risk factor and having a group of individuals not exposed to the risk factor, and following the two groups over time to determine the occurrence of a disease. Its strengths include that multiple outcomes can be measured for anyone’s exposure, and unlike a cross-sectional study, it can measure both incidence and prevalence of a disease. The weaknesses associated with this study are that it is costly, time-consuming, and prone to bias due to loss of follow up. Additionally, there is the risk of participants moving between one exposure category and the participants’ behavior being altered by being in the study.
The third method is the randomized controlled trial study design, which falls under the broad group of interventional studies, usually done in laboratories and clinical studies and trials to determine the effects of drugs or procedures. It is mostly employed to determine the cause-effect relationship between an intervention and an outcome. The strengths of this study include the fact that it is most suitable for assessing the effectiveness of intervention from an epidemiological study and that additionally, it provides a strong basis for statistical reference. Weaknesses include that it is costly, time-consuming, and there is a threat of generalisability since results might not necessarily be representative of all individuals.
A review of the cross-sectional study article: – ‘The association between time perspective and alcohol consumption in university students: cross-sectional study’ by Beenstock, J., Adams, J., & White, M.
The objective of this study was to determine the relationship between time perspective and hazardous alcohol consumption. Concerning time perspective, individuals who have a more future-oriented time perspective tend to consider the future outcomes of their present actions, unlike their counterparts with a more present-oriented time perspective. Hazardous alcohol consumption was to be as measured by the Alcohol Use Disorders Identification Test.
The study was a cross-sectional study of the association between future time perspective and hazardous alcohol consumption, which took place from February to April 2008 in two faculties at a University in Northern England, UK (Beenstock et al., 2010).
The participants were three hundred and twenty-two undergraduate students. Any student registered in a course with a taught component was eligible to take part in the study. For the recruitment of the participants, Deans in the two Faculties of Humanities and Social Science and Agriculture and Engineering invited staff to volunteer a few minutes of their lecture time into the study. The lecturers who heeded to the call made available a lecture of their choice, and students registered for these lectures were invited to take part in the survey. The background characteristics considered in this study were the participants’ ages, genders, years of research, religions, ethnicity, and socio-economic position. For gender, there were both men and women; for the year of study, there were first, second, and third-year students; for religion, there were atheists, Christians, and others, while for ethnic groups, there were White British and others.
The research was done through the distribution of questionnaires to the participants. The variables in the surveys were future time perspective and hazardous alcohol consumption. Future time perspective was measured using the Consideration of Future Consequences Scale. Higher scores in the scale indicate a more significant consideration of future consequences for immediate actions, while a lower score would indicate less review of future outcomes. Hazardous Alcohol Consumption, on the other hand, was measured using the Alcohol Use Disorders Identification Test (AUDIT). The scale identified harmful and hazardous drinking, as well as the possibility of dependence. Any score greater than or equal to eight (8) marked dangerous alcohol consumption.
The key findings in this cross-sectional study was that the undergraduate student participants with a more oriented future time perspective were less likely to score above the threshold that marked hazardous alcohol consumption. On the contrary, a higher incidence of hazardous alcohol consumption was found in students who had less oriented future time perspectives (Beenstock et al., 2010).
The strengths of the study include well-tested, and thus more accurate and reliable measures employed to determine future time perspective (the Consideration of Future Consequences Scale) and hazardous alcohol consumption (the Alcohol Use Disorders Identification Test).
Limitations identified included the setting in which the data was collected, which may have allowed bias on the grounds of social desirability since it was impossible to be entirely sure that the participants did not discuss the answers before completing the questionnaires. There was also the possibility of the participants underreporting or over-reporting their alcohol consumption. Another limitation was the possibility of non-response bias since only 70% of students registered for the lectures took part in the study, unlike the 97% attendance rate. Additionally, religious and ethnic groups in small numbers were lumped together, which leads to the possibility of inaccurate statistics. Finally, data obtained was entirely cross-sectional, and no conclusion could, therefore, be drawn on the direction of causation between future time perspective and alcohol consumption.
The authors indicate the value of the research to be as hypothesized, that future time perspective is related to hazardous alcohol consumption, and that students with more future-oriented time perspective were less likely to meet the threshold of hazardous alcohol consumption. The authors, however, acknowledge that the findings cannot be confirmed to be generalizable due to the limitations discussed. Finally, the authors recommend the implementation of interventions to help students focus more on the future outcomes of their immediate actions if it is confirmed that future time perspective is indeed related to hazardous alcohol consumption.
A review of the cohort study article: – ‘Alcohol consumption and alcohol counseling behavior among US medical students: a cohort study’ by Frank, E., Elon, L., Naimi, T., & Brewer, R.
The study aimed at determining which factors affect alcohol counseling practices among medical students. It was a cohort study done on medical students in 16 US medical schools, who graduated in 2003.
All medical students graduating in 2003 were eligible to participate in the study, which was to occur in the following three parts: in the first year of orientation (summer/autumn 1999), entrance towards (usually in the second or third year, depending on the school) and in the final year. The background characteristics of the participants were age, gender, ethnicity, and marital status, among other considerations like school size, medical school research ranking from the US National Institutes of Health, the strength of religious identity, and whether the medical school was private or public. For age, the average age was 24 years for first-year students. The genders used in the study were both female and male, while for ethnicity, there was Black/African American, Asian, Hispanic, White, and Other. Concerning marital status, there were married, unmarried couples, single, divorced, and widowed categories.
The study was done by administering questionnaires to the participants. The questionnaires were conducted in three stages over time, and these were upon joining the medical school (summer/autumn 1999), in the participants’ entrance towards (in the second or third year of study), and finally in the final year of study of the participants. At the entry-level, 2080 students were eligible to complete the survey, but only 1846 responded (89%). On entry towards, 1982 students were eligible to take part in the study, but only 1630 responded (82%), while among the final year students, 1901 students were eligible, but only 1469 responded (77%) (Frank et al. 2008). Typically, the questionnaires were administered after semi-mandatory activities like after the orientation lunch, after an exam, or at the end of class to foster maximum participation. In schools that exhibited lower response rates, the Dillman’s five-stage mailing process was used to complete the survey.
The questionnaires sought answers to three core questions: the frequency of consumption of any alcoholic beverage in the past month, quantity drunk on average on the days that the participant drunk in the past month, and finally the frequency in the past month that the participant had five or more drinks on one occasion. Based on answers given, the participants were classified into one of three groups: excessive drinkers, non-excessive drinkers, and non-drinkers. An excessive drinker was one who reported at least one occasion where they consumed five or more drinks, or men who drank more than two drinks a day on average, or women who drank more than one drink a day on average. Drinkers who did not meet this threshold were classified as non-excessive drinkers, while those who took no alcohol in the past month were non-drinkers. For smoking, the parameters were whether the participant had smoked at least 100 cigarettes in their entire life, frequency of present smoking, and how much they had smoked in the past month.
In the study, 43% of men and 24% of women reported excessive alcohol consumption in the previous month, with little change in frequency over time. Additionally, only a quarter of final year students did a routine assessment of their patients’ drinking patterns. The students’ perception of the relevance and frequency of alcohol counseling had a significant association with their training in alcohol counseling. Finally, it was found that only half of the final year students were highly confident on their ability to discuss alcohol with their patients (Frank et al., 2008).
The strengths of the study were high response rates and a broader representative sample from participants. The limitations encountered included that the data obtained was survey data rather than qualitative data from interviews, which is more reliable. There was also the aspect of difficulty in validating the data given in the questionnaires. In finality, the authors recommended that medical schools ought to consider routinely training their students to counsel and screen patients for alcohol misuse, and additionally discourage excessive alcohol consumption among students.
A review of the randomized control trial article: – ‘A critical review of public health interventions aimed at reducing alcohol consumption and increasing knowledge among pregnant women’ by Crawford-Williams, F., Fielder, A., Mikocka-Walus, A., & Esterman, A.
The study aimed at determining the effectiveness of printed health education documents in improving knowledge of alcohol consumption in pregnant women, change the attitudes to drinking during pregnancy, and incidentally reduce alcohol consumption among pregnant women.
The study was a two-armed randomized control trial conducted at the women’s outpatient clinic in the Women’s and Children’s Hospital (WCH) and the Birthing and Assessment Unit at the Lyell McEwin Hospital (LMH), South Australia. Baseline data collection was done in November 2014 to July 2015, while following up data collection was concluded in January 2016. Pregnant women aged 18 years and above, in the second trimester of their pregnancy, residing in South Australia and who had agreed to be followed up upon delivery were eligible to take part in the trial. The recruitment of participants was done at the two sites concurrently. The trial had 161 eligible and consenting participants, where 82 were randomized into the intervention group, while 79 were put in the control group (Crawford-Williams et al., 2014). This allocation was done through a computer-generated list of random numbers to avoid bias.
The trial was done through the recruitment of participants, as discussed above, who were then asked to fill out a baseline questionnaire given to them. Participants in the intervention group were subsequently given an information booklet to go through with their families and partners thoroughly and were instructed to make use of the mocktail recipes therein throughout their pregnancies. Women in the control group were given standard ante-natal care, which may or may not include advice on alcohol. Follow-up questionnaires were also forwarded to all participants after delivery. The questionnaire sought information on knowledge of the participant on the effects of consuming alcohol during pregnancy, their attitudes towards pregnant women who drank alcohol, their alcohol consumption before and during the pregnancy, their partners’ alcohol consumption before and during the participant’s pregnancy, the partner’s influence on the woman’s drinking, as well as demographic information. Knowledge regarding the effects of taking alcohol during pregnancy was measured as a continuous variable using true/false/unknown statements. Attitudes towards alcohol consumption during pregnancy was measured on a five-point Likert scale with responses from ‘strongly agree’ to ‘strongly disagree’ and comments like ‘I would have positive feelings towards a pregnant woman drinking alcohol.’ The range of the attitude score was 8 to 40, with a higher overall attitude score showing a negative attitude towards women consuming alcohol during pregnancy. The consumption and views were the two main variables in this trial. Other variables on which data was also collected included maternal age, socio-economic status, gestation, and education level.
The trial found that more than half of the 161 participants had consumed alcohol in the 12 months previous to the pregnancy. 83% of these consumed an average of seven drinks of alcohol per week with wine as the most common beverage. 76% of the participants had partners who regularly consumed alcohol, with the most common beverage being beer. 28.6% of the participants revealed that they would be less likely to drink during pregnancy if their partners encouraged them to stop. On knowledge of the effects of alcohol consumption during pregnancy, the intervention group improved by 9% in correct answers in comparison to the control group. Likewise, the intervention group improved in the mean attitude score by 1.4 points, a statistically significant figure (Crawford-Williams et al., 2014).
The limitations disclosed by the trial included a large number of non-returned follow-up questionnaires, thus reducing data available for analysis. There was also the issue that the participants majorly consisted of well-educated, high income-earning Caucasian women, hence the statistics cannot safely be generalized. The authors opine that in the future, it would be better to conduct the trial on larger sample size and to exclude women who never consume alcohol. The authors further recommend for further research to be done with samples of women who continue to drink alcohol during pregnancy to conclusively determine the effectiveness of public health intervention in changing the drinking behavior among pregnant women.
Conclusion
In conclusion, it can be said that epidemiological research is the foundation of public health. This is attributable to the central role it plays in the identification of various risk factors for diseases, and the general promotion of health among the public through employing various intervention measures upon conducting epidemiological studies and trial among the population. Statistics obtained are used by policymakers and in public health practice to ensure the highest health standards are maintained among the people. Without it, disease outbreaks would go unresolved.
Epidemiological research has refined its methods over the years to provide more accurate and reliable statistics for the greater good of the public. It is recommended that epidemiological study that takes the form of participatory research to be more widely used by epidemiologists to curb the critical limitation encountered in public health research, which is the difficulty in the validation of statistics obtained.