Epidemiological research – this is how it is done at the Medical University of Warsaw
What do you do at the Department of Environmental Hazard Prevention, Allergology and Immunology of the Medical University of Warsaw?
The Department of Environmental Hazard Prevention, Allergology and Immunology of the Medical University of Warsaw is a place that, for me, is synonymous with public health. It is hard for me to imagine a more interdisciplinary facility. We deal with all kinds of research here, starting from big and strategic epidemiological projects, through clinical trials, and ending with analyses of the Internet space and fight against disinformation. We also prepare various types of expert opinions and reports on selected health problems and the health care system. And this is only part of our activity. Teaching should also be mentioned. This academic year we will teach about 60 different subjects. To make this possible, the Department employs specialists in various fields of medical sciences. Working in such a team is an extremely valuable experience in itself. This is thanks to professor Samoliński, who not only establish the Department but also built this team.
You recently completed the “MedFake” project. What was this project about?
The “MedFake” project concerned the broadly defined building of trust in vaccinations and was financed by the National Research and Development Center (NCBR) as part of the “GOSPOSTRATEG II” competition. We conducted it together with the Public Health Department. Its implementation occurred mainly during the CoViD-19 pandemic and, consequently, the related “infodemic”. It was then that trust in vaccinations began to be undermined on an unprecedented scale. Initially, it may have seemed that the pandemic would be a “bucket of cold water” for people who questioned the rationality of vaccination. It turned out to be quite the opposite. Emotions and human fear were used to spread fake news on this topic. Unfortunately, that has influenced society’s awareness and now we have to deal with the consequences. But this is not only Poland’s problem. Already in 2019, the World Health Organization identified vaccine hesitancy as one of the 10 greatest threats to health globally.
For me personally, it was an extraordinary opportunity to cooperate with many great scientists from other fields, because the project was carried out by a consortium with Medical Center of Postgraduate Education (CMKP), University of Social Sciences and Humanities (SWPS) and Kozminski University (ALK). I had an opportunity to listen to fantastic lectures by colleagues from SWPS, for example about risk perception in the context of parents’ fears of vaccine injury, or a team from ALK analyzing the spread of disinformation on the Internet.
But the tasks carried out by our team from the Medical University of Warsaw were equally interesting. We have conducted a number of studies with various methodologies. For example, we analyzed the attitude towards vaccinations in selected professional groups including medical staff but also teachers. We also carried out a big representative study on a group of young residents of our country, checking how deeply misinformation had shaken their trust in vaccinations, which was supervised by doctor Tomaszewska. We also obtained data from district sanitary and epidemiological stations on the level of vaccination over the last 10 years and analyzed this data using the BigData approach, comparing it with external databases. That was dealt with by one of our epidemiologists, doctor Samel-Kowalik. And this is only a small part of the team’s activity within the project. Based on our research and analyses, we attempted to create tools that could help in the fight against ubiquitous disinformation.
What kind of tools were they?
Those were mainly educational tools intended for primary schools, but not only. Doctor Tomaszewska, together with a group of outstanding educators, developed lesson plans for teachers, combining our and their experiences. The result of this cooperation was, for example, a history lesson program devoted to the plague epidemic. Children could hear about the crazy ideas people came up with to avoid the Black Death or to try to recover from it. For example, keeping a smelly goat at home or burning horse manure was supposed to prevent infection. Regarding treatment, the popular therapy was placing a pigeon on wounds. As part of the project, we also designed two educational comics for children and a guide for parents titled “A world without vaccinations?”, where we show the consequences of diseases against which vaccinations currently protect us. Parents can read there, among others, about the recently deceased Paul Alexander who spent almost his entire life in the so-called “iron lung” after suffering from polio. Doctor Kłak from our team was responsible for preparing the guide.
Interestingly, we were inspired to take this type of action by the words of our colleagues from SWPS, who mentioned the possibility of “vaccinating” themselves against disinformation. The idea was to develop the habit of critical thinking in young people. It is very important to teach these types of skills from an early age.
How important is cooperation with medical staff and local governments in building trust in vaccinations?
In my opinion, medical staff who have direct contact with the parents of the child being vaccinated play a key role here. It is only necessary that they are properly prepared for it. We know perfectly well that talking to a parent who denies the rationality of vaccinations is difficult. And if we add time constraints, additional responsibilities related to medical documentation, stress and lack of preparation in conducting such conversations, we have a simple recipe for disaster. Artur Białoszewski, together with specialists in communication, pediatrics and vaccinology, has produced a video guide for medical staff on dealing with people refusing vaccinations. Doctor Mularczyk-Tomczewska, in turn, coordinated work on “Good practices in preventive vaccinations – recommendations for primary care providers in the field of preventive vaccinations for children and adolescents”. The document was created based on information we obtained from dozens of meetings with the staff of vaccination points and experts. For me, these meetings were extremely valuable because we talked to people involved in organizing vaccinations at every stage – from registration clerks to medical directors. We also met a lot with local governments which can also play an important role in building trust in vaccinations due to their knowledge of local specifics and the trust of residents.
All these activities were possible thanks to the marvelous people who work at our University. Such big projects are handled by entire teams and are additionally supported by a group of experts. And what I mentioned at the beginning is crucial here: interdisciplinarity. When talking about the University’s team, it is necessary to mention the specialized design departments that support us all the time, from writing project applications, through launching and conducting projects, and ending with reporting. Due to the enormity of formal and legal requirements, no big project could currently be carried out without their support.
What about other projects implemented by the Department?
Our Department has specialized in project implementation from the very beginning. Epidemiology of Allergic Diseases (ECAP), Global Adult Tobacco Survey (GATS), projects under the National Health Program (NPZ), “MedFake” and now “MetALL”. I have mentioned just the biggest ones – we also carried out a number of smaller studies in parallel. I became involved with the Medical University of Warsaw 18 years ago during the implementation of the Epidemiology of Allergic Diseases project in Poland. Professor Samoliński invited me to cooperate because he was looking for a methodologist familiar with questionnaire research and sample selection methods. Later, he entrusted me and doctor Tomaszewska with field coordination of the study. I was responsible for fieldwork and she was responsible for organizing the work of our outpatient clinics in individual locations. This is how my adventure with the University began. It was something amazing. As a very young man, I was given a very responsible task. From my current perspective, it is now much easier for me to understand what a big challenge I faced at the time. But it was probably then that my passion for working in projects was born, which continues to this day.
How did the Epidemiology of Allergic Diseases research work in practice?
It was an extremely interesting project because, firstly, it involved both children and adults, and secondly, it included both a questionnaire and an outpatient part. And there is also the matter of scale. The project was to cover a group of 22,500 people. To make things harder, there was also an expectation that the results should be representative.
Of course, we started by refining the research methodology. We had general assumptions that had to be translated into specific practical solutions. We knew that we had to rely on the international ECRHS II and ISAAC questionnaires, but the question arose how exactly to use them. The first one was designed for adults, the other one for children. After long discussions, we decided to use a unified tool for both children and adults. That required combining both tools in an balanced way. The idea turned out to be a hit, but its implementation was not easy at all. These questionnaire tools are very similar, but to some extent different. The challenge consisted in deciding which differences were worth keeping and which were not. Each additional question lengthened the questionnaire, so the interview.
Another problem we encountered was the sample selection. While in the case of the 20-44 age group we had a few options to choose from, reaching children aged 6-7 was a bigger challenge. We considered using educational institutions for this purpose, but that would require using completely different sampling methods for the groups of children and adults. Finally, we decided to use the Polish central system for registration of residents (PESEL), which was then administered by the Ministry of Internal Affairs and Administration. After obtaining necessary consents, the Ministry selected our sample according to our guidelines. We call such samples “individually marked” ones. At that time, it was a very convenient sample selection method for us because, apart from the first and last names and registered address of residence, we immediately knew the age and sex of the subject, which is particularly important in health-related research. First, we notified randomly selected participants about the study and invited them to participate. Then our interviewers visited them and completed the questionnaires. In the next step, some of the respondents were invited to our outpatient clinics where they were interviewed, subjected to skin tests and spirometry, and finally diagnoses were made. That was how we examined 20,000 people, of whom approximately 5,000 went through the full outpatient procedure.
Do you recruit study subjects in the same way for all your projects?
No. There are many methods of selecting a sample and recruiting people for studies. Most of our research is based on address-based samples. We used this method in the international Global Adult Tobacco Survey (conducted in 2008-2010 – editor’s note) which we conducted in Poland at the request of WHO and CDC. In this case, we drew not PESEL numbers but residence addresses from the TERYT database operated by the Central Statistical Office. In this way we obtained 8,000 addresses. Half of them were located in rural areas and half in urban ones, which does not fully correspond to the actual distribution of population in Poland, but such were the top-down guidelines imposed by the CDC and WHO for all countries participating in the project. Since the use of tobacco products depends strongly on the place of residence, that strategy was justified from the perspective of subsequent statistical analyses. I can also add here that a procedure of weighing the data (adjusting it to the distribution of the country’s population) was completed to ensure that the results would be representative of the entire adult population of Poland. The data weighting procedure is very often used in population studies but, of course, it raises some controversy because it is a form of “manipulating” data. But let’s leave this topic, because it is a strictly academic issue. Returning to the sampling in the Global Adult Tobacco Survey – a quite complicated multi-stage sampling scheme was used there. As a result, bundles of addresses emerged, where distances between them were relatively small, which made it easier to carry out the field research. We call this procedure “bundling”. This is another common technique used while selecting study samples.
Selecting potential subjects at random is one thing, but convincing them to take part in the project is quite another. How do you do it?
Even the best selected research sample will not give us reliable results if the people selected for the study do not participate in it. The problem is serious because the trial completion rate has been decreasing since the early 1990s. It used to be on average around 80-90%, now it is about 25%. Of course, we have slight differences between rural and urban areas. Differences also result from sex and age. Convincing a man aged 30-44 to participate in a study is almost impossible. This group is a big challenge not only in the context of population research, but also in the context of broadly defined prevention.
It is worth mentioning something that we commonly call “response rate”, but often not quite as defined. Generally, we have many different types of indicators that describe the research sample. The problem begins when you try to calculate the response rate. Let me give you an example. Let’s assume that we randomly selected for a study 100 people whom we know by name and address. Finally, 30 of those randomly selected took part in the study. So, calculated in a simple way, the response rate would be an unimpressive 30%. But it turned out after a more detailed check that, for example, 10 of those selected were dead, 30 more had moved to another place and could not be reached, and 30 actually refused to participate in the study. Therefore, it makes sense to ask whether we should count the response rate based on the 100 people or on the 60 people who could actually be able to take part in the study. In the latter case, our response rate reaches 50%, which looks better. To avoid such doubts, we have a few different indicators describing the response rate of the research sample, each of which is calculated in a slightly different way. Everything would be fine if we used them correctly, that is, according to the definition. I recommend those interested in this topic to contact doctor Samel-Kowalik from our Department, who is an expert in this field.
Can anything be done to improve response rates?
How to encourage people to participate in such studies? This is a very difficult task. Especially since what is attractive to one group of people will not work for another. Many research centers conducting population studies have methods that work for them to some extent. In some cases it is acceptable to use various types of incentives; for example, if someone takes part in the study, they will receive a voucher or a gift. This is intended to compensate them for their time and inconvenience associated with participating in the study. These are relatively effective methods, but not for all groups. For example, a drugstore voucher is unlikely to be particularly effective in the previously mentioned group of men aged 30-44. Additionally, the higher the material status, the lower the perceived value of such an incentive.
It should also be remembered that such incentives are prohibited in some types of research. We have recently started implementing a very big MetALL project – a cohort study where the Medical Research Agency prohibits the use of this type of incentives for subjects. Even though participation in the study is assumed to be beneficial for the participants, the possibility of learning more about their own health condition is not a convincing argument at all for some people, and there are even people who perceive it as a threat. We are aware that the lack of material incentives to participate in the study will make recruitment difficult.
You mentioned that it is most difficult to encourage men in their prime. And who is the easiest to convince to participate?
Seniors are quite a “friendly” group. They often have more time and participation in the study is a kind of “attraction”, a departure from their daily routine. However, in their case other types of difficulties arise. For example, the verification of credibility of the researcher: is he or she is really the person they claim to be? Additionally, when dealing with this group we must take account of neurodegenerative diseases and communication problems.
People running households who are not gainfully employed and students also willingly respond to invitations. They are more flexible in terms of availability and it is easier to arrange a convenient date with them.
Interestingly, the fact that these groups are more willing to participate in the study may also be a challenge to some extent from the sampling perspective. Both groups that are statistically more willing to participate and those that do it less often have an adverse impact on representativeness of the study. From the researcher’s perspective, the ideal situation is when no factor, such as age, sex or financial status, affects the willingness to participate in the study. Of course, this situation is only hypothetical. In fact, these factors significantly determine whether a given person will let a researcher or interviewer into their home or not, or whether they will go to a designated clinic and undergo a medical examination.
And what should be done in such a situation to maintain representativeness?
There are many different ways to deal with this situation. Of course, the basic ones include all kinds of activities aimed at increasing the overall response rate. In the Epidemiology of Allergic Diseases study, mentioned above, we did several methodological experiments to check what incentives work best. We sent one group a standard notice about the study along with information about the possibility of taking medical tests at our outpatient clinic. The second group received the same notice, but with a voucher in the shape of a banknote showing the market value of these tests. The third group received the notice and a leaflet explaining in more detail the tests we performed on study participants in the outpatient clinic. Then we checked which of the incentives convinced people more effectively to take part in the questionnaire survey and which of these people later came for the outpatient examination. Communication is also a very important element in this context, as it can lend credibility to the project and its staff.
Another feasible solution is to use more advanced sampling methods, taking into account that different groups of respondents have different preferences regarding participation in various studies. Since we know that it is difficult to recruit men aged 30-44, we can randomly select more people from this group at the very beginning. That way we can “thicken” the sample because we know that most likely only 1 out of 10 randomly selected people will take part in the study. Therefore, the initially drawn sample is not representative, but the actual sample may be considered as such. However, detailed and up-to-date information on response rates in individual subgroups are needed to use this method.
The “data weighting” procedure has also been used for many years, especially in epidemiological studies on large populations, where conclusions are made based on the results obtained from the research sample. In the simplest terms, representativeness means that the structure of the study sample corresponds to the structure of a given population. Based on a study conducted, for example, on a thousand people, we want to draw conclusions about 30 million adult inhabitants of Poland. This is possible, but only if the sample is representative of the selected population. As I have already mentioned, the willingness of different people to participate in the study varies. Thus, the so-called “sample skewness” may occur, which means that the results we obtain will not reflect the actual situation well. If this happens, corrective weights are introduced – for example, one person from the category who participates in the study less often is counted as 1.5 people, and a person from the category of people who participate in the survey more often is counted as 2/3rds of a person. At first, it seems unintuitive, but every professional statistical analysis tool supports such functionality in a very simple way.
Finally, I will mention another alternative, which is various types of quota samples. In this case, we determine in advance how many people belonging to a given category are to effectively participate in the study, and then we carry out recruitment or research until these values, i.e. quotas, are achieved. Theoretically, quota samples are classified as qualitative sampling methods, i.e. methods that we do not consider representative. However, additional techniques are now being considered to add an element of sampling to the procedure for selecting subjects or respondents. Opinions on this subject are divided. Some researchers note that such a trial is still not random, despite these measures. Others, in turn, point out that samples obtained in this way are much closer to the structure of the population, which, for example, limits the need to use weights.
You mentioned a project on multimorbidity that you are currently starting. What will this study look like?
The MetALL project, launched on June 1, concerns the impact of chronic inflammatory processes resulting from allergies on the risk of occurrence of certain lifestyle diseases and broadly defined multimorbidities. It is a cohort study. This means that we select a group of people and observe them prospectively, i.e. “forward”, for a next few years. In this particular case, this will be a group of 6-7-year-olds, their parents and, if possible, their grandparents. We will recruit children from the non-exposed group (without atopy), in primary health care clinics, and those from the exposed group in allergy clinics. Then, we will monitor their health for 6 years. We have provided for three steps of contact with the patient in this project. The first one is the enrollment to the study, during which we collect blood and perform a series of measurements. The next step is a mid-term analysis, after three years, when we repeat most of the tests from the beginning. The last contact takes place at the end of the project, where we conduct the same tests again.
Moreover, throughout the duration of the project, once a quarter, we will contact the parents of our subjects and send them online forms regarding, for example, current infections or other disturbing symptoms.
We are currently in the first stage of the project. We are planning a pilot for the first quarter of 2025 and recruitment for the main part of the study should begin in the middle of next year. We are implementing this project together with the Medical University of Białystok.
How large group of children will you study in this project?
At least 4,000 subjects will participate in the study. Half of them are children and half are their parents. Additionally, we will collect information about the other parent and grandparents to better determine risk factors and to be able to draw conclusions about the family history of allergies.
We will start with 4,000 people, but we are aware that some of them will drop out within the 6 years of the study for various reasons. Our job is to do everything we can to keep as many people in the cohort as possible. It will be a challenge, but we have a very experienced and interdisciplinary team.
And what is the purpose of this study?
We want to demonstrate that children and parents with allergies experience chronic inflammation, which favors the development of other lifestyle diseases and, in the long run, may lead to multimorbidities. This applies to cardiovascular, metabolic, oncological and infectious diseases, among others, and recently we are also considering the impact on various types of mental disorders. Since we are starting the study with a relatively young group, where the risk of developing multimorbidities in the next 6 years is limited, we will also focus on changes in parameters that may indicate the risk of occurrence of the mentioned diseases in the following years.
The scientific value of the research you conduct cannot be overestimated, but can an average person also benefit from it? How does your work translate into benefits for patients?
I hope that our research will be used by decision-makers to design systemic actions. If it turns out that people with allergies are at a significantly higher risk of cardiovascular diseases, appropriate procedures and therapeutic paths can be introduced. For example, introduce a recommendation that allergy patients should routinely be referred to a cardiologist, similarly to diabetics who are sent for ophthalmological examinations.
I really want the state’s health policy to be based on evidence-based medicine using our experience and research results. This will make it possible to better plan preventive measures, provide additional follow-up for certain groups of patients and reach them earlier with appropriate education. It is also possible that development of medicine in this area will offer other preventive measures for prevention before getting ill.
Interviewed by Iwona Kołakowska
Communication and Promotion Office