Prevention of T2DM: the setting
“What’s the point of treating illness and then sending the patient back to the conditions that made them sick in the first place” – Sir Michael Marmot
No one would argue with the international evidence from well-designed clinical trials showing that lifestyle interventions can prevent or significantly delay the onset of type 2 diabetes in ‘at-risk’ persons. But people live in the real world of over-and-under nutrition, overcrowded urban spaces and sedentary workplaces. To address the obesity and diabetes risks generated by such conditions, a comprehensive two-pronged approach that focusses on both behavioural risks and unhealthy socio-environmental circumstances is needed.
The concept of settings or micro-environments such as the individual’s home, school and workplace, and sectors ie broader influences such as trade, transport and monetary policy, was first articulated in relation to obesity in the 1990s. This approach applies to diabetogenic environments as well as obesogenic environments and, with the world facing an unprecedented triple crisis (environmental, financial and non-communicable diseases), is more relevant than ever.
In this article we focus specifically on type 2 diabetes prevention in the settings where people live, learn, work, pray and play:
The old saying that home is where the heart is neglects to mention that home is also where the pancreas is – and where a person’s first degree relatives can mostly be found.
Having a first degree relative with diabetes is a significant risk for the future development of diabetes. In addition, living in the same household implies sharing health and lifestyle behaviours. This applies to smoking as well as food and physical activity choices. Smoke free home environments are import on two counts: to avoid harmful ‘second hand’ smoke inhalation and to to set in train and re-inforce healthy lifestyle habits.
Health promotion and diabetes prevention programs should work with families of people with type 2 diabetes to reduce their shared modifiable risks.
Addressing over-and-under nutrition and ensuring a healthy intrauterine and early childhood environment is vital to health in general, physical resilience and preventing or reducing the development of metabolic diseases. Home is where it all starts – and often finishes – and is therefore arguably the single most important setting for the prevention of type 2 diabetes. However, it must be remembered that the home environment is strongly influenced by what happens in the broader social, physical and economic environment, and optimising home environments may require a greater focus on sectors, not just settings.
Nursery (Kindergarten) and school settings
The nursery and school settings are of central importance to the prevention of type 2 diabetes because it is one of the key avenues where children learn eating and physical activity cultural norms. In many cases, school may be a stronger influence in setting lifestyle habits of children than even the home environment.
In the case of food and nutrition this is particularly important in national education systems where the nursery or the school provides a lunch time meal. Sadly, high-calorie foods are increasingly available and promoted at schools. The internationally famous chef and nutrition activist, Jamie Oliver, has graphically demonstrated the poor quality of food in UK schools and English campaigned vigorously to improve it.
Opportunities for incidental physical activity (PA), formal PA classes, and formal school sporting activities have all declined in recent decades. However, there is reasonably good evidence of the effectiveness of school-based interventions for nutrition and PA from several countries. These include specific studies demonstrating that school interventions can reduce the development of type 2 diabetes.
(Picture courtesy of the Oxford Health Alliance) Massive technological advances since World War II have led to increasing automation of work and sedentary work practices, in many cases leaving progressively less need for people to expend much more energy on their work tasks than that required to pull levers, or a press buttons on a keyboard. While some types of work remain physically active, sedentary work is common across the income spectrum from people working production processes on factory floors to taxi drivers who sit all day, to people in high level jobs who work on computers or sit in tense meetings for long periods each day or who travel long distances to and from work
Stress (work overload, interpersonal conflict, pressure for precision/accuracy or to meet deadlines) in the workplace may also play a part. Kumari and colleagues reported that air traffic controllers have a high prevalence of diabetes due to the highly demanding nature of the job, and that job strain and a lack of social support at work are associated with increased levels of glycosylated haemoglobin in non-diabetic populations. There is considerable anecdotal evidence from India that call centre workers have higher rates of type 2 diabetes due to sedentary tasks, shift work, reduced sleep quality, and poor diets.
In reviewing the international literature, an evidence based guideline on the prevention of type 2 diabetes found that worksites are an effective setting for community-based interventions aimed at promoting healthy eating, especially worksite programs that include environmental modifications and involve family members. There multiple examples of the effectiveness of workplace interventions for nutrition, overweight and obesity, and physical inactivity, particularly in countries such as the US where health insurance is tied to employment benefits. Return on investment for employers in terms of productivity and other parameters is reportedly high.
In some countries, churches play a significant role in influencing the way people live. For example, in Pacific Island countries, which have among the highest rates of diabetes worldwide, churches and the clergy are invariably involved in major health meetings and are active in lifestyle health promotion programs for healthy eating and physical activity.
Healthy neighbourhoods are vital to diabetes prevention and should be, clean, safe, smoke free, walk-able and cycle-able and include open spaces for play and community activities.
Since 2008 more people live in cities than not and people worldwide are flocking from rural to urban centres at the rate of at least 60 million per year. Already one billion people worldwide live in overcrowded urban slums. This has serious implications for the pre-conception and intra-uterine environment, and the first 1000 days of life that are so vital to the avoidance of obesity, diabetes and cardiovascular problems in later life. Indeed, studies have shown higher rates of diabetes in slums versus the whole population background. Consequently, efforts to reduce poverty can also bring returns in preventing diabetes.
Neighbourhoods exposed to particulate air pollution have also been shown to increase the likelihood of diabetes. Neighbourhood is equally important in more affluent communities. Urban sprawl has been shown to increase the likelihood of obesity, an important risk for type 2 diabetes, and new studies are showing an association between diabetes and proximity to green or open spaces. Fortunately, there is a global movement to improve the physical activity environment through better urban design that includes cycling infrastructure and ‘traffic calming’ methods, and by making urban neighbourhoods more walkable. This has the added value of supporting social participation (lack of social participation is a factor in all-cause mortality) and reducing petty street crime. Additionally, neighbourhood food environments can be improved by using zoning laws to reduce the proportion of fast food outlets, as has been shown in California.
The more micro-environments such as home, workplace, and local community’ settings are mediated by broader sectors. Macro-influences include fiscal and monetary policy, transport, agriculture and food production, trade, urban design and public policy and laws, and there is growing evidence that these can be modified to improve health problems like diabetes and related NCDs.
It is particularly encouraging that the link between health, social and human development, and the economic and physical environment is increasingly recognised in global health and business policy. This awareness is manifest in the United Nations Political Declaration on NCDs, the World Economic Forum Global Risk Report and the UN’s Rio+ 2020 Sustainability Conference Outcomes Document, and is already leading to action on NCDs that has the potential to impact positively on the prevention of diabetes at the ‘settings’ level.
^ Swinburn B et al. Dissecting obesogenic environments: The development and application of a framework for identifying and prioritizing environmental interventions for obesity. Preventive Medicine 1999;29:563-570.
^ Fox MK et al. Availability and consumption of competitive foods in US public schools. J AM Diet Assoc 2009;109(Suppl. 2):S57-S66.
^ Hill JO et al. Scientific statement: Sociological determinants of prediabetes and type 2 diabetes. Diabetes Care 2013;36:2430-2439.
^ Kumari M et al. Prospective study of social and other risk factors for incidence of type 2 diabetes in the Whitehall II study. Arch Intern Med 2004;164:1873-1880.
^ Colagiuri R et al. Evidence based guideline for the primary prevention of type 2 diabetes. Diabetes Australia and the NHMRC 2009.
^ Astell-Burt T. Is neighbourhood green space associated with a lower risk of type 2 diabetes mellitus? Evidence from 267,072 Australians. In press -Diabetes Care 2014;37:1-5.
^ United Nations General Assembly. Political declaration of the high-level meeting of the General Assembly on the prevention and control of non-communicable diseases. Sixty-sixth session, Agenda item 117, New York 2011.
^ United Nations. The future we want: Outcomes document adopted at Rio+20. New York 2012.