Socioeconomic Inequality and Type 2-Diabetes Mellitus

At the CAPHRI research institute in Maastricht, a 5-member team led by Professor Hans Bosma is working on a large-scale study on socioeconomic inequality and Type 2 Diabetes Mellitus (T2DM). In this, they are looking at underlying factors such as the living and working environment of people with a lower socioeconomic status (SES) and to what extent these hinder a healthier lifestyle (and thus also hinder lowering the risk of T2DM). The first results were published recently on the influence of SES on the development of T2DM and the mediating role the psychosocial work environment plays. The team used data from over 8000 participants in De Maastricht Studie for their research.

Inequality

Hans has always been fascinated by inequality and his interest in the subject was initially sparked by inequality in students’ educational careers. He observed that primary school students with the same CITO test scores1, but not belonging to the same SES groups, receive different recommendations for secondary education and therefore end up making different school choices with all the consequences this has for their educational attainment and future careers. Later, during his PhD at the Department of Medical Psychology, he collaborated on a large-scale study on health inequalities in cardiovascular disease; this further piqued his interest.

"I then realised that inequality not only affects your educational career and the choices you make in it, but it is also related to your health and your lifespan or how likely someone is to have a heart attack," Prof Hans Bosma said.

1 CITO test scores indicate whether pupils should progress to pre-vocational secondary education (VMBO), senior general secondary education (HAVO) or pre-academic education (VWO) in the Netherlands.

Lifestyle and the risk of Type 2-Diabetes Mellitus

Triggered by the research findings on socioeconomic inequality in relation to cardiovascular disease, Hans wanted to continue the research and set to work with his team using the available diabetes data from De Maastricht Studie. Type 2 Diabetes Mellitus, popularly known as "age-related diabetes", is the most common form of diabetes and about 1.1 million people in the Netherlands suffer from this chronic condition. The disease is often associated with an unhealthy lifestyle and individuals are therefore advised to adjust and, where possible, improve their lifestyle by, for example, eating healthier, not smoking and exercising more.

However, Hans' team believes that less obvious factors can also play a role in this. In their research project to address socioeconomic inequalities in T2DM, they are therefore looking at individuals' living and working environments and to what extent these hinder healthier lifestyles.

Postdoc researcher Rachelle Meisters explains: "As a GP or internist you can provide a lot of advice about what people should change in their lifestyle, but sometimes the living and working environment simply does not provide the opportunities for this, especially in low-SES individuals."

"What if you have a sedentary job, a stressful job or are not in control when and for how long you can take a break at work?", Rachelle continues. "Do you even feel like going for an evening walk in a neighbourhood that doesn’t feel safe? If the gym or healthier food is simply too expensive for you, what do you do?" Again, this is all linked to lower income or education levels.

Low SES

Socioeconomic status has a significant impact on a person's overall health. Previous research using data from De Maastricht Studie has already shown that individuals with a low income or lower education level, are at higher risk of developing Type 2 Diabetes Mellitus, than those from a higher-income group or with a higher education level. Indeed, individuals with lower SES are even twice as likely to develop T2DM than those with higher SES. Socio-economic inequality in T2DM has thus already been demonstrated, but how can this be explained and what factors may play a role in it?

The INJUST team (CAPHRI)

The INJUST research team from left to right: Prof. Dr Hans Bosma (Professor of Social Epidemiology), Dr Annemarie Koster (Senior Lecturer, Universitair Hoofddocent uhd), Dr Rachelle Meisters (Postdoc researcher), Jeroen Albers (PhD student) and Bengisu Sezer (PhD student).

Autonomy at work

Bengisu Sezer, a PhD student on Hans's research team, recently published initial findings on the importance of the psychosocial work environment in this issue, especially the degree of control over work.

The results show that when you have the freedom at work to schedule your own breaks, decide on your tasks and contribute to shaping the work culture, this autonomy has a significant impact on whether or not you develop T2DM. The study thus highlights the importance of 'empowering' workers, especially those in lower-paid jobs, in shaping their working days. This benefits not only the productivity of these lower-paid workers, but also their overall health.

Figure 1

Other factors

However, this psychosocial work environment explains only a small part of the effect of Socioeconomic Position on T2DM. Further research into other factors is needed to explain the remaining part. The research team led by Prof. Dr Hans Bosma and Dr Annemarie Koster has already found the first indications that stress, feeling inferior and being more fatalistic in life play a role in this. This is more common among lower socio-economic groups. Jeroen Albers, a PhD student in the team, is also taking a closer look at the immediate living environment, in addition to the working environment, looking at green spaces, air pollution and the proximity of fast-food restaurants and fritures (chip shops). With regard to the latter risk factor, the research results are already in and, contrary to all expectations, no unambiguous link was found between the number of chip shops in the neighbourhood and diet or the development of T2DM in people with both low and high Socioeconomic Positions.

Research Impact

The research thus shifts the focus to risk factors other than those most people are familiar with, and the 5-member team hopes this will free Type 2 Diabetes Mellitus from the stigma attached to this chronic condition.

Rachelle: "Diabetes is sometimes called a disease of affluence, because nowadays we have access to food everywhere all the time. People with diabetes are then quickly thought to be lazy: they don't move, they don't exercise, they just hang out on the sofa and eat too much and too much of the wrong food."

This stigma, often wrongly, places the responsibility completely on the individual, while the diet and lifestyle of people with T2DM is also co-determined by socioeconomic environmental factors related to their SES and the chronic stress of living in low Socioeconomic Positions.

Hans therefore hopes that, partly as a result of this study, GPs and internists will no longer limit themselves to giving diet and exercise advice. He hopes they will start the conversation with the patient about to what extent this advice is feasible in the patient's eyes. In addition, he wants to convince employers to give lower-paid and lower-skilled employees more control over how they organise their working day, as this has a positive effect on their health.

Also read: “Socioeconomic Position and Type 2 Diabetes: The Mediating Role of Psychosocial Work Environment – The Maastricht Study

Written by: Tonita Perea y Monsuwé

Photography: Joey Roberts

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