Discuss what public health approaches can and should be undertaken to reduce the rising prevalence of metabolic disease across the population.

HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Metabolic Disease Epidemic
Introduction 1
Objectives 2
Facts figures and definitions 2
Burden of Disease attributable to Non-communicable Disease 4
Factors contributing to obesity and metabolic disease 5
Approaches to obesity prevention 9
Obesity prevention and the nutrition transition 12
Summary of key points 14
Conclusion 14
References 15
This module will consider the prevalence causes and potential public health actions to address the metabolic disease epidemic which is occurring in Australia and internationally. The term metabolic disease refers to diseases that have interrupted normal metabolic function and includes obesity particularly abdominal obesity impaired glucose tolerance insulin resistance type 2 diabetes and altered lipid profiles known to be associated with increased vessel damage. The metabolic disease epidemic is an important current issue in public health nutrition due to the high prevalence in developed countries the increasing prevalence associated with the Nutrition Transition in developing countries and the challenges associated with addressing the issues. These diseases place enormous economic costs on the health care systems of all countries and are among the greatest contributors to global morbidity and mortality.
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
When you have completed this module you should be able to:
Discuss why the metabolic disease epidemic is a public health nutrition priority
Describe and assess what contributes to the development of metabolic disease at a population level and groups most at risk and
Discuss what public health approaches can and should be undertaken to reduce the rising prevalence of metabolic disease across the population.
Facts figures and definitions
The terms described below are relevant to understanding the metabolic disease epidemic. The Deakin university unit Diet and Disease (HSN301 or HSN703) provides more detail on the conditions outlined below if you have undertaken one of those units then this first section (two pages) should serve to refresh your knowledge and if you have not then you are encouraged to read some of the references in more detail.
A term used to describe the series of demographic social and economic changes occurring in low and middle income countries which result in rapid shifts in dietary patterns and lifestyles. In countries undergoing nutrition transition communicable diseases and under-nutrition co-exist with an increasing prevalence of non-communicable and metabolic diseases and over-nutrition -the worst of both worlds. The nutrition transition is discussed in further detail later in this module.
Nutrition transition
Metabolic conditions which are non-infectious and non-transmittable (as opposed to communicable diseases which are infectious). This term refers to similar states of ill health as the term metabolic disease but also includes Cardiovascular Disease (CVD) cancers and respiratory disease. Non communicable diseases are usually chronic in nature (long duration) and most are linked to obesity. These health issues are estimated to be the leading cause of death in the world representing 63% of deaths annually with 80% of these occurring in low-and middle-income countries (WHO).
Non communicable diseases (NCDs)
Obesity is typically defined as a Body Mass Index (BMI) = 30 though some definitions also incorporate other measures such as waist circumference (indicating abdominal obesity) and percentage body fat. People who are obese or overweight (BMI 25-29.9) are at higher risk of Type 2 Diabetes cardiovascular disease cancer joint problems respiratory problems and some psycho-social issues. According to the World Health Organisation (2014) there are around 2 billion adults overweight of those 768 million are obese.It is also estimated that over 200 million school-age children are overweight making this generation the first predicted to have a shorter lifespan than their parents (World Obesity).
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
According to the 2011-12 Australian Health Survey
In these Australian data overweight/obesity rates varied across different population groups. The rate was higher for men (70.3%) than women (56.2%) and higher for older people (74.7% of adults aged 65-74) than younger people (38.4% of adults aged 18-24) in the 2011-12 survey. Additionally according to previous data a third of Australian adults living in areas of most disadvantage were obese (33%) which is almost double that of people in areas of least disadvantage (17%). Where people lived also influenced prevalence with more adults in outer regional and remote Australia being obese (31%) than those in major cities (23%). These figures reflect some of the greater health risks seen for disadvantaged groups as discussed in Module 3.
Figure 1: Overweight/Obesity rates across different population groups in Australia
Older people -65-74 years (74.7%)
Younger people -18-24 years (38.4%)
Men (70.3%)
Women (56.2%)
Outer regional and rural areas (31%)
Major Australian cities
Most disadvantaged (33%)
Least disadvantaged (17%)
In 2011-12 63.4% of Australians aged 18 years and over were overweight or obese comprised of 35.0% overweight and 28.3% obese. A further 35.2% were of normal weight and 1.5% were underweight. Prevalence of overweight and obesity in adults aged 18 years and over has continued to rise to 63.4% in 2011-12 from 61.2% in 2007-08 and 56.3% in 1995. However the prevalence of overweight and obesity in children aged 5-17 has remained stable at 25.3% in 2011-12. (ABS)
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Burden of Disease attributable to Non-communicable Disease
The Global Burden of Diseases Injuries and Risk Factors Study (GBD) is a large and detailed collection and representation of data to quantify levels and trends in health. The GBD provides a tool to quantify health loss from hundreds of diseases injuries and risk factors. GBD research incorporates both the prevalence of a disease or risk factor and the relative harm it causes. The Australian data indicates that:
Non-communicable diseases are the leading contributors to burden of disease
High body mass index and dietary risks now both out-rank tobacco smoking as the top risk factors contributing to the burden of disease
Go here to view the Australian data and here to look at the whole GBD program and compare with other countries.
Diabetesis diagnosed when a persons insulin response to carbohydrate ingestion is significantly impaired.Globally there are 374 million people living with diabetes with an estimated further 50% undiagnosed. Most of these cases are type 2 diabetes which is caused by lifestyle factors including physical inactivity unhealthy diet and overweight/obesity.People with diabetes are at higher risk of health conditions such as cardiovascular disease kidney failure and eye disease. In Australia diabetes is the 6thleading cause of death and contributes 10% to all deaths. Those living in disadvantaged areas are twice as likely to have diabetes as those living in least disadvantaged areas. For further information on diabetes in Australia please see the Diabetes Australia website (https://www.diabetesaustralia.com.au/diabetes-in-australia).
Cardiovascular disease comprises diseases and conditions of the heart and blood vessels. Globally it is estimated that 17.3 million people died from CVD in 2008 with a projected figure for 2030 of 23.6 million. Given CVD is known as a disease of affluence it is perhaps surprising to find that the majority of deaths (80%) are seen in lower to middle income countries. (WHO: http://www.who.int/cardiovascular_diseases/en/). In Australia according to the 2011-12 Australian Health Survey 1 million people (4.7%) reported having CVD.
Cardiovascular disease (CVD)
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Essential Task 4.1: Read
Read Nader P et al. 2012 Next Steps in Obesity Prevention: Altering Early Life Systems to Support Healthy Parents Infant and Toddlers Childhood Obesity vol. 8 no. 3. pp. 195-204.
This paper should firstly reinforce and extend your knowledge from Module 1 regarding the importance of early influences across the lifecourse and developmental and intergenerational effects. Take note of any new information about the lifestages considered most important for obesity prevention.
Following this you are encouraged to consider:
What are some key features of a systems approach?
Look at the model (figure also shown below) and take note particularly of the two way (bidirectional) arrow between the individual/family and social and physical environment support.
What are some relevant/useful examples of systems interactions for nutrition promotion and obesity prevention?
Factors contributing to obesity and metabolic disease
This infographic from the Institute of Medicine titled Obesity: complex but conquerable presents some key facts and figures on obesity particularly on five contributing factors suggested as areas which need improvement.
Another infographic from the Obesity Society titled Potential Contributors to Obesity illustrates the complexity of the determinants of obesity and presents a more detailed lsit of factors that have been raised in the literature as potential contributors.
This complexity of the genesis of obesity is nicely summarised by Deakins Head of the School of Exercise and Nutrition Sciences Professor David Crawford:
The obesity epidemic is a complex phenomenon (and) this complexity exists at a number of levels The underlying influences on our eating and physical activity are not straightforward involving a range of personal social and structural factors that are likely to vary in their relative importance for different populations and for different sub-groups within the same population. In addition there are powerful global commercial and political interests at stake. (Crawford et al 2010.)
The complexity referred to has been operationalised by many researchers (if you are interested in this topic for postgraduate study a potential unit of interest is HSN734 Obesity Prevention). In the following reading youll find both a discussion around a focus for obesity prevention but also an example of a model that could be applied to ensure obesity and its sequelae might be addressed.
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Essential Task 4.2: Read
Please read this paper by Giskes et al an interesting systematic review looking at which environmental factors significantly contribute to the development of overweight/obesity. Please note which ones were the strongest drivers for obesity. Giskes K et al. 2011 A systematic review of environmental factors and obesogenic dietary intakes among adults: are we getting closer to understanding obesogenic environments? Obesity Reviews vol. 12 no. 5. e95-e106.
A community systems framework of early intervention of childhood obesity with feedbacks between individuals and the environment (Nader et al. 2012).
The complexity referred to by Crawford above has also been operationalised by Davidson and Birchs socio-ecological model (figure shown below). The socio-ecological model highlights a similar but slightly different conception of causality suggesting that obesity and metabolic disease will be affected by individual interpersonal and environmental factors. The figure below focusses
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Supplementary Task: Read
This paper provides a fascinating insight into a key element of the food environment: ultra-processed foods. Monteiro C et al. 2013 Ultra-processed products are becoming dominant in the global food system Obesity Reviews vol. 13 no. S2 pp. 21-28.
The discussion of the spread of these foods to middle-income countries is linked to the discussion of the nutrition transition at the end of this module.
on how these different levels can influence the weight status of a child but a similar model can be applied to a variety of health outcomes and life stages.
The environmental or ecological drivers affecting food choice and physical activity can include:
The food environment includes the type of food that is available the cost of food how it is marketed and policies regulating the food supply. The food environment is becoming increasingly globalised with highly processed foods transported around the world and often available for relatively low prices. The international nature of the food environment makes regulation challenging because of differences between countries and because trade agreements related to food are usually focused on economic and political rationale thus unrelated to nutrition.
The built environment includes the type of buildings neighbourhoods transportation systems and other man-made features of the landscape e.g. roads pavements buildings sports facilities parks escalators/stairs. These features affect peoples ability to participate in physical activity (eg.
Source: Davison KK Birch LL. Childhood overweight: a contextual model and recommendations for future research. Obes Rev. 2001;2:15971
HSN302: Population Nutrition. Module 4: Metabolic Disease Epidemic
Supplementary Task: Watch
You might find it interesting to watch this short (