Chronic Diseases, Health Systems, and Inequalities: A Public Health Perspective

Shahid Akhter, Consulting Editor, FEHealthcare, spoke to Prof. Gilles Paradis, Dept. of Epidemiology, McGill University, Canada, on the sidelines of the CCDC Scientific Symposium, to discuss the challenges and opportunities in public health and chronic disease epidemiology.

 

What are the biggest methodological challenges in studying chronic diseases across different populations?

There are many challenges and opportunities associated with the epidemiology of chronic diseases. I work in and come from a high-income country. Therefore, our experiences here differ from those in other countries due to variations in geography, social systems, economic systems, wealth, and more. Epidemiology is the study of populations, which is vital to understanding disease dynamics. And therefore, all such studies address the same methodological issues associated with population studies, that is, being able to correctly measure factors that are related to outcomes, and the outcomes that we're interested in are chronic diseases in particular in our country.​ 

This includes conditions such as cardiovascular disease, chronic pulmonary disease, diabetes, hypertension, and cancers. Now, the challenges that we identify can also be applied to other diseases, including communicable diseases, such as Covid, for example, influenza, and other communicable diseases.

Some of the challenges relate to obtaining precise measurement of the risk factors that we are interested in assessing. Some of these risk factors, such as smoking, may seem overly technical; however, smoking is likely the most significant behavioral risk factor for many chronic diseases worldwide. But smoking takes on many different forms, depending on the age of an individual and their socioeconomic condition. Additionally, the impact of smoking varies depending on the individual's country of origin. We have conducted smoking initiation studies in children in Canada to show that there are many different ways that smoking affects the health of the children and the way that smoking is initiated and then ultimately maintained. Thus, although smoking may appear to be a simple behavior, it is actually complex regarding measurement and the assessment of its impact on population health, individual health, and its evolution over time. The same holds true for numerous other behavioral types. Diet is another one, even much more complicated because it is determined by various cultural and social factors. Other behaviors include physical activity and, in a different context, sexual behaviors that are linked to certain communicable diseases. These are all behaviors that we try to measure as objectively as possible in epidemiological studies, but that requires a lot of careful attention to details in how you measure them.​ ​We associate such conditions with the biological and genetic factors that are associated with disease. These are complex phenomena to measure, although you can take a blood draw and measure blood cholesterol or blood glucose in an individual with relative accuracy. ​However, the dynamic that changes, or the physiology of lipid and glucose metabolism, is vital to disease origin. Assessing these biological factors requires careful attention to detail. 

 

Which core public health function is most challenging to deliver today?

There are probably as many public health systems as there are countries in the world. Public health has common characteristics across the world, related to some basic functions that are essential for improving and maintaining the health of populations,​ and these include surveillance of disease. ​Understanding the trends of the occurrence of disease in populations​ is important. Another basic function includes the protection of health in populations,​ and that's in particular with relation to communicable diseases. How do we ensure that measles outbreaks, for example, are controlled or are prevented? Then another function is related to health promotion. This is how we can intervene to promote the optimal health of individuals and communities throughout their lifespan. 

There is an important evaluation function that assesses the impact of public health initiatives, similar to how physicians conduct tests or physical examinations to determine if a treatment is effective for a specific patient. As public health practitioners and professionals, we need to evaluate whether or not what we do in populations actually has an impact. ​In this regard, societies do these functions differently. 

 

Your thoughts on the biggest obstacle to strengthening its public health system in India

The complexity of the public health system in India arises from its large population and the significant variability in geography, culture, socio​-economic distribution, and climate, which includes many different types of climates across the country. ​Additionally, the political system's complexity stems from having a central government alongside regional governments. Regional governments interact with policies that can improve health in many cases, while in other cases, these policies may not be as beneficial for health improvement. There are many challenges in all countries, but especially in India due to its size, population, and the number of children aging. This confluence of factors makes public health management very complicated. The challenge, along with the necessary resources, should not be overlooked. To be able to manage such vast differences in a population requires vast resources. In this discussion, we are considering more than just financial resources. Yes. While money is important for completing the work, it is also essential to have adequate resources, including the right infrastructure and well-trained personnel. So training in public health requires many people to have a university degree, often a PhD, in a variety of fields, be it epidemiology, demography, or sociology. Physicians with training in public health play a crucial role. Consequently, the distribution of this expertise is uneven across India. 

 

How does Canada’s vast geography and regional inequalities affect the delivery of public health services?

Canada's total population, less than 40 million, spans a vast territory. Therefore, a significant portion of the country remains sparsely populated. For example, Toronto, Vancouver, and Montreal are a few urban centers that have large populations and face typical urban issues. These issues include social inequalities, violence, and housing problems, among others. So in Canada, trying to deliver public health services to such a diverse population is a challenge. Our public health system has become highly regionalized, with regional public health units taking responsibility for the health of a specific region. However, the availability of resources to these specific subgroups remains a significant challenge. I am referring to the Aboriginal populations and northern communities in Canada, which experience higher rates of diseases, such as tuberculosis and other communicable diseases, that are less prevalent in the rest of the country. Therefore, the underserved northern parts of Canada have a sparse population.

Why is the link between public health and primary care still so weak in most countries?

There are specific challenges that are very difficult to overcome and data that need to be addressed on a day-to-day basis worldwide. There are many models of public health organizations that exist, from decentralized models, like they have in the United States, to more highly centralized models in other countries.

These models depend on societal values that determine how society organizes and finances both healthcare services and public health services. The same considerations apply to public health: they include how society is prepared to fund public health services and how it organizes and manages public health issues. A major challenge for most systems is managing the interface between healthcare services and public health, particularly in primary care. Family physicians, family doctors, nurse practitioners, and other members of the primary care ecosystem should collaborate as partners with public health to implement preventive activities in an organized and systematic manner. Unfortunately, the implementation of these activities occurs infrequently and is often inadequate. In most countries, the link between public health and primary care is significantly weak and needs substantial improvement. This challenge exists globally.