- Causes of diabetes and impacts on Australia's health system and economy
Overview
2.1Diabetes is a complex multiorgan disease with a wide spectrum of causes, risk factors, and symptoms. Understanding what diabetes is, its prevalence in Australia, and its health and economic impact provides an important contextual foundation for examining efforts designed to prevent and treat the disease.
2.2In discussing current understandings of the causes of and risk factors for diabetes, focus is placed on Type 1, Type 2, gestational diabetes, as well as rare forms, such as Type 3c diabetes. With obesity identified as one of the major risk factors for Type 2 and gestational diabetes, this chapter also discusses the current medical understanding of the causes of obesity, and its relation to diabetes.
2.3In the course of this inquiry the Committee heard that Australia is facing a diabetes epidemic. The subsequent sections thus examine the available data pertaining to current rates of both diabetes and obesity in Australia, as well as likely future trends. Where possible, this data is placed into an international context.
2.4Diabetes is a relentless condition that deeply impacts the lives of patients and their families. The disease also has significant broader impacts on various aspects of society. The final section considers the impact of diabetes across the health system, and examines available data on direct and indirect costs in an effort to develop a better understanding of the impact of the condition on Australia’s economy.
What is diabetes?
2.5Diabetes mellitus is a chronic metabolic disease characterised by elevated levels of blood glucose (sugar). The main symptom is the passing of large quantities of sweet-tasting urine, which gave the condition its name: diabetes from the Greek word meaning ‘a siphon’ as the body channels excess fluid; and mellitus from the Greek and Latin terms for honey.
2.6The underlying cause of diabetes is a deficiency (either relative or absolute) of the hormone insulin, or resistance to the action of insulin (‘insulin resistance’). Insulin is produced in beta cells of the pancreas, and it is the principal hormone for lowering blood glucose levels. While there are multiple forms of diabetes, the most common include Type 1 diabetes, Type 2 diabetes, and gestational diabetes.
2.7Type 1 diabetes is caused by an autoimmune destruction of insulin-producing beta cells in the pancreas. As a result, the body cannot produce insulin to self-manage blood glucose levels, and the patient experiences an absolute deficiency of insulin. People living with Type 1 diabetes must regularly monitor their blood glucose levels and administer insulin either via multiple daily injections or an insulin pump.
2.8Type 1 diabetes is a lifelong condition for which there is no known cure. In most cases, Type 1 diabetes is developed and diagnosed in childhood or adolescence, although it can also present later in life.
2.9Type 2 diabetes is a result of both impaired insulin production and the body’s resistance to its action. Patients with Type 2 diabetes thus experience a relative deficiency of insulin. Some people living with Type 2 diabetes need to administer insulin either temporarily or regularly; others manage their condition with medications and adjustment to their diet and lifestyle.
2.10Type 2 diabetes is diagnosed when blood glucose levels reach a certain threshold. The condition tends to develop over many years. When patients have higher than normal blood glucose levels, but before reaching the threshold for diagnosing Type 2 diabetes, they are considered to have pre-diabetes.
2.11Specialists note that the precise levels of glucose or thresholds that define diabetes have been revised several times in the past. As such, there is some uncertainty as to the exact number of those diagnosed with pre-diabetes or Type 2 diabetes.
2.12There are several different blood tests that are used to diagnose diabetes. According to Diabetes Australia, the tests include:
- Glycated haemoglobin (HbA1c): a non-fasting test that measures average blood glucose over the last two to three months. An HbA1c of 6.5 per cent (48 millimoles per mole – mmol/L) indicates likelihood of diabetes; between 6.0 per cent to 6.4 per cent would indicate pre-diabetes.
- Fasting blood glucose: a fasting test that measures the blood glucose level at a particular time. A fasting blood glucose level of 7.0 mmol/L or more indicates diabetes; between 6.1 mmol/L and 6.9 mmol/L is likely pre-diabetes (also called impaired fasting glucose).
- Non-fasting (or random) blood glucose: a test that measures the blood glucose level after easting. A non-fasting (or random) blood glucose level of 11.1 mmol/L or more indicates diabetes; between 7.8 mmol/L and 11.0 mmol/L is likely pre-diabetes.
- Oral glucose tolerance test (OGTT): a test that combines fasting and non-fasting blood glucose level measurement. A fasting blood test is first administered; then a sweet drink is consumed and the blood glucose is measured after one and then two hours. Diabetes is likely if the fasting level is 7.0mmol/L or above, or the 2-hour level is 11.1 mmol/L or above.
- Gestational diabetes mellitus (GDM) is a form of diabetes that occurs during pregnancy. In most cases, pregnancy-related diabetes resolves after the baby is born. Women who had gestational diabetes and their children have an increased risk of developing Type 2 diabetes later in life.
- There are also a number of rarer forms of diabetes that are collectively classified as ‘other types of diabetes.’ These include, for example:
- Type 3c diabetes: a form of diabetes that occurs when the pancreas is damaged or removed. In most cases, this is a consequence of pancreatic cancer, pancreatitis (inflammation of pancreas) and cystic fibrosis.
- Maturity-onset diabetes of the young (MODY): an inherited, non-autoimmune form of diabetes. It is usually a non insulin-dependent variant, and it occurs before the age of 25.
- Latent autoimmune diabetes in adults (LADA): an autoimmune form of diabetes that occurs in adults (unlike Type 1 which is usually diagnosed earlier in life), with slowly progressive beta cell failure.
- Checkpoint-inhibitor-induced diabetes (CPIDM): a very rare type of diabetes that is triggered by Immune Checkpoint Inhibitors, which are used for treatment of various forms of cancer.
- Many people living with rare types of diabetes require similar management as people living with Type 1 diabetes, such as the daily administration of insulin and regular blood glucose monitoring.
Causes of diabetes
2.16The causes of diabetes are complex, and vary for each type. Much of the evidence provided in support of this inquiry discussed the ‘risk factors’ for diabetes. Risk factors are attributes, characteristics or exposures that increase the chances of developing a disease. Some of the risk factors that impact the development of diabetes are modifiable – for example modifying or changing a type of diet or levels of physical activity to prevent or delay the onset of Type 2 diabetes; others are non-modifiable, such as genetic factors that cause Type 1 diabetes.
Type 1 diabetes
2.17The exact causes of Type 1 diabetes are not known. It is widely accepted, however, that both genetics and environmental factors likely contribute to Type 1 diabetes. The genetic component seems to play a central role, and researchers have identified genetic markers that can predict the development of Type 1 diabetes.
2.18Researchers believe that genetically susceptible individuals develop the disease following an environmental trigger. The Centre for Diabetes, Obesity and Endocrinology Research (CDOER), based out of the Westmead Institute of Medical Research, noted that environmental factors associated with Type 1 diabetes included vitamin D deficiency (particularly early in life), obesity, insulin resistance and viruses.
2.19As part of the inquiry, the Committee heard evidence discussing the possibility of a COVID-19 infection being an environmental trigger that could influence the development of Type 1 or Type 2 diabetes. Multiple submitters, including the Department of Health and Aged Care, referenced emerging evidence suggesting that there may be a link between COVID-19 and new-onset Type 1 and/or Type 2 diabetes.
Type 2 diabetes
2.20The Committee received evidence identifying multiple and complex risk factors for Type 2 diabetes. The extent to which these risk factors may interact to cause Type 2 diabetes is a matter of ongoing research and debate.
2.21It is increasingly recognised that there are significant genetic and family-related risk factors for Type 2 diabetes. Individuals with a family history of Type 2 diabetes or obesity, and those from non-Caucasian ethnic groups, are at a higher risk of developing the disease. Additionally, an individual having previously been diagnosed with gestational diabetes, or whose mother had gestational diabetes during pregnancy, is also at higher risk of Type 2 diabetes.
2.22A person’s age is another factor for developing Type 2 diabetes. Body weight and fat tissue tend to increase with age, while muscle mass decreases. These changes impact the body’s ability to metabolise glucose and as a result older people are at a higher risk of Type 2 diabetes.
2.23In addition to non-modifiable risk factors such as genetics and age, there are several modifiable factors that influence the development of Type 2 diabetes. Being overweight or obese is a major modifiable risk factor for the development of Type 2 diabetes. According to analysis from the Australian Institute for Health and Welfare (AIHW), 55 per cent of cases of Type 2 diabetes are due to overweight and obesity – making it the strongest risk factor for the disease. Indeed, the Endocrine Society of Australia submitted that ‘[t]he strong inter-relationship between type 2 diabetes and obesity has given rise to the term diabesity.’
2.24While also acknowledging obesity as the greatest risk factor for Type 2 diabetes, Dr James Muecke AM, ophthalmologist and Australian of the Year in 2020, suggested that obesity is not a root cause of diabetes, but rather a symptom of underlying issues. Dr Muecke AM explained that in his view, ‘obesity is only a marker for poor metabolic health.’
2.25The Committee heard that while excess weight and obesity are associated with Type 2 diabetes, the two are not always linked. The Department of Health and Aged Care emphasised that ‘while obesity is a significant risk factor for type 2 diabetes, not all individuals living with obesity develop diabetes, and diabetes can occur in individuals who are not obese.’ Further illustrating this point, the CDOER highlighted that 20 per cent of people with Type 2 diabetes are not living with excess weight or obesity.
2.26Certain medications can also present a risk for Type 2 diabetes. For example, the Committee heard that taking antipsychotic drugs or corticosteroids can raise an individual’s risk of Type 2 diabetes by increasing their body weight and insulin resistance.
2.27The Endocrine Society of Australia further noted that specific medical conditions including polycystic ovarian syndrome (PCOS), obstructive sleep apnoea, and Cushing’s syndrome, appear to be risk factors for developing Type 2 diabetes. Hepatitis C Virus co-infection, lipodystrophy (a group of diseases that cause abnormal distribution of fat throughout the body) and living with human immunodeficiency virus (HIV) all present risk factors.
2.28Poor diet, smoking, and physical inactivity can also impact the development of the disease. Indeed, the George Institute for Global Health cited AIHW data showing that poor diet is the second strongest risk factor for Type 2 diabetes after overweight and obesity.
Gestational diabetes
2.29The risk factors for gestational diabetes are very similar to those for Type 2 diabetes. Genetic makeup places some individuals at a greater risk of gestational diabetes. Specifically, having a family history of Type 2 diabetes or a particular ethnic background can increase a person’s chance of developing the condition.
2.30The Australian College of Nurse Practitioners submitted that ‘poor nutrition, and physical inactivity can contribute to the development of GDM [gestational diabetes mellitus]’. According to the Australian College of Midwives further risk factors include certain medications and the presence of PCOS.
2.31The Committee also heard that an individual’s age and weight before becoming pregnant influence the likelihood of developing gestational diabetes during pregnancy. Women who become pregnant at older age and who are overweight or obese at the time of pregnancy are more likely to develop gestational diabetes. In some cases, women who develop gestational diabetes were in fact living with undiagnosed pre-diabetes before the pregnancy.
2.32In addition, hormones produced by the placenta can contribute to the development of gestational diabetes. While a woman is pregnant, the placenta produces certain hormones to help maintain the pregnancy, including estrogen, cortisol and human placental lactogen. These hormones can block insulin, leading to insulin resistance.
Causes of obesity
2.33Obesity is a significant risk factor for Type 2 and gestational diabetes. As such, efforts to prevent obesity should drive a reduction in these forms of diabetes.
2.34The Obesity Collective defined obesity as ‘a chronic relapsing condition where extra body fat affects a person’s health.’ There is a broad consensus among contributors to the inquiry that no single factor causes or explains obesity. As the Australian Food and Grocery Council (AFGC) emphasised:
In 2009, the National Preventive Health Taskforce completed the most comprehensive examination (before or since) of overweight and obesity in Australia. No single factor or group of factors was identified as being strongly associated with, and therefore potentially driving, the increases in the weight of Australians.
2.35The Committee heard that there was a range of modifiable and non-modifiable factors that can contribute to excess weight gain. These include, for example:
- Genetics and physiological factors such as an individual’s ethnicity, family history of obesity, appetite, metabolism, satiety (how easily someone feels full) and weight distribution
- Eating patterns from infancy (including the length of breastfeeding) through to adulthood
- Sleep quality and routines
- Exposure to stress
- The use of certain medications
- The environments in which people live.
- The Australia and New Zealand Obesity Society (ANZOS) emphasised that interaction between these different factors is critical for understanding obesity:
Simple explanations of the development of obesity often focus on an imbalance of energy where calories (energy) intake exceeds energy expenditure, leading to weight gain. However, a complex and diverse range of factors contribute to a positive energy balance, and it is the interaction between a number of these influences, rather than any single factor acting alone, that is thought to be responsible.
2.37A common theme raised throughout the inquiry was the idea that Australia may have an ‘obesogenic’ environment: an environment that contributes to people developing obesity. The Royal Australasian College of Physicians (RACP) explained:
Obesogenic environments encourage adults and children to consume more calories than are metabolically required… [These are] modern environments that promote unhealthier foods, stress, physical inactivity and weight gain.
2.38Ms Justine Cain from Diabetes Australia, which is the national peak body for people living with diabetes and those at risk, expressed her concern regarding this trend:
Very, very scarily, the experts say our country’s environment is obesogenic. That means it is easier to become overweight or obese in Australia than it is to maintain a healthy weight.
2.39The idea of an obesogenic environment implies that obesity is partly attributable to systemic or societal factors, which shifts focus from individuals living with obesity, to the broader environment. In addition, there are other determinants of health that contribute to obesity. The Obesity Collective, for example, identified income, education, and housing situation as some specific examples of determinants of health that can increase the risk of obesity.
2.40The Committee acknowledges that socio-economic factors have a significant impact on obesity. As Mr Stephen Bali, the NSW Parliament Member for Blacktown, submitted: ‘The problem is that people in lower socio-economic communities do not have the same financial means to access healthy food options and enjoyable physical activity in the same way wealthier communities do.’
2.41ANZOS further noted that lower socio-economic communities often have more difficulty accessing healthy food options. Indeed, these communities are often characterised by a higher density of fast-food outlets, and fewer public spaces for exercise such as parklands or beaches. It is also the case that dealing with long commutes to work and services can leave ‘less time to plan and undertake desirable health behaviours.’
Scale of the problem
2.42Similar to other diseases, diabetes can be quantified in terms of its incidence and prevalence. As Professor Jonathan Shaw, the Deputy Director of Clinical and Population Health at the Baker Heart and Diabetes Institute explained, ‘prevalence is the number of people who have the condition at any time in the population’ (i.e. total cases), and ‘incidence is the rate at which new cases are occurring.’
2.43The major sources of data and information about diabetes in Australia are the AIHW, the National Diabetes Services Scheme (NDSS), and the Australasian Paediatric Endocrine Group state and territory-based registers. Many of those who provided information to the Committee about the incidence, prevalence, burden or general trends associated with diabetes in Australia drew from these sources.
Current levels of diabetes
2.44Diabetes Australia submitted that approximately 1.5 million Australians are currently living with all types of known, diagnosed diabetes. Multiple submissions noted that the true prevalence of diabetes in Australia is likely higher, as this figure only includes people who have received a formal medical diagnosis and are registered with the NDSS.
2.45NDSS data indicated that the number of people in Australia with specific forms of diabetes are as follows:
- 137,000 people have Type 1 diabetes (this group represents about nine per cent of the Australians with some form of diabetes)
- 1.3 million people have Type 2 diabetes (about 87 per cent of diabetes cases)
- 44,000 people were diagnosed with gestational diabetes in the past year (about 3 per cent of diabetes cases)
- 12,000 people have some other form of diabetes (about one per cent of diabetes cases).
Diabetes Australia added that about 500,000 Australians currently live with undiagnosed Type 2 diabetes.
2.46In some instances, it can be difficult to diagnose the correct type of diabetes. For example, Dr Shanal Kumar, endocrinologist at the Prince Charles and Princess Alexandra Hospitals in Brisbane, told the Committee that this was particularly the case for Type 3c diabetes, which is sometimes incorrectly classified as Type 2 diabetes. The misclassification can thus somewhat distort the picture of diabetes cases.
2.47A significant number of Australians are also currently living with pre-diabetes. Diabetes Australia cited evidence estimating that at least two million Australians have pre-diabetes; Diabetes Victoria estimated that this number could be as high as 2.5 million. The Consumers Health Forum of Australia submitted that an even greater number – possibly as high as almost one-third of Australians – may have pre-diabetes. This is a high-risk group: according to Diabetes Australia, about ‘one-third of people living with prediabetes will develop type 2 diabetes within 10 years.’
Trends and future forecasts for diabetes
2.48Diabetes is the fastest-growing chronic or non-communicable disease in Australia. The Royal Australian College of General Practitioners (RACGP) cited research indicating that Australia has seen a steady increase in the prevalence of diabetes (i.e. the number of people currently living with the condition) over the years, which reflected a global trend.
2.49NSW Health similarly emphasised this trend, and submitted that overall, different sources of data including the Population Health Survey, the Australian Bureau of Statistics National Health Survey and the 2021 Australian Census ‘all show that there has been an increase in prevalence [of diabetes] over time.’
2.50Impact Obesity, a health promotion charity, referenced AIHW data about the trends over time pertaining to the prevalence of diabetes, which showed that the number of Australians living with all forms of diabetes increased by 183 per cent between 2000 and 2021, from 460,000 to 1.3 million.
2.51Diabetes Australia also highlighted that the prevalence of diabetes is increasing in Australia, noting that in 1989–90 about 1.2 per cent of Australians had diabetes, compared to 5.6 per cent in 2023. In discussing the future trends, Ms Cain from Diabetes Australia told the Committee that:
By 2050, if we don't change the trajectory of what's happening with the diabetes epidemic, 3.1 million Australians—that's eight per cent of the projected population—will be living with diabetes.
2.52The Committee received evidence suggesting that the incidence (i.e. the number of new cases developed in a population in a specific time period) of Type 1 diabetes is increasing. The CDOER informed the Committee that Type 1 diabetes is becoming more common worldwide, with cases growing by about three per cent annually. This increase is also seen in Australia. The Centre commented that this ‘rate of increase cannot be due to genetic changes, as the increase is too fast.’
2.53The Rural Doctors Association of Australia, however, submitted that ‘the incidence of Type 1 diabetes has remained relatively stable for two decades.’ Professor Shaw from the Baker Heart and Diabetes Institute further clarified that:
The incidence of type 1 diabetes has generally been increasing in almost every country over the last 40 to 50 years. It's probably plateaued in some countries, and I think it's probably plateaued here over the last decade or so.
2.54A recent study drew upon data from 1990 to 2019 to examine changes to Type 2 diabetes prevalence, deaths, and disability-adjusted life years (DALYs) (a measure of the burden of a disease) in Australia, and compared these markers with 14 other similar countries including the United Kingdom, United States, Canada, New Zealand, Norway, Singapore, and Germany. The study found that of the 15 peer countries, Australia had the fourth highest Type 2 diabetes prevalence, and was the fourth worst for Type 2 diabetes-related death rates.
2.55The Medical Technology Association of Australia (MTAA) submitted that due to Australia’s ageing population ‘over time, an increasingly large portion of Australia’s population – as much as half of it by the middle of the century – would be at risk of developing type 2 diabetes on account of ageing alone.’ MTAA further noted that, based on migration trends, a growing percentage of Australia’s population will also ‘be at risk of developing type 2 diabetes on account of ethnic or cultural background alone.’
2.56The increasing prevalence of Type 2 diabetes is not unique to Australia; according to the World Health Organisation, this trend is occurring worldwide. The International Diabetes Federation estimates that Type 2 diabetes is growing globally: 10.5 per cent of the world’s population aged between 20 and 79 is currently living with diabetes, and this number is set to rise to 12.2 per cent by 2045.
2.57The Committee heard evidence that younger people are increasingly being diagnosed with the condition. The Department of Health and Aged Care cited research which suggested that people were previously diagnosed with Type 2 diabetes after the age of 50, ‘but diagnosis in younger adults, adolescents and even children is increasingly common.’
2.58Indeed, NDSS data shows that among Australians under the age of 39, the incidence of people developing Type 2 diabetes (i.e. rates of new cases) increased by 37 per cent between 2012 and 2022. For young people under the age of 20, the number of newly-diagnosed type 2 diabetes cases increased over the past decade by 18 per cent.
2.59Professor Louise Baur, Fellow at the RACP told the Committee about the rising number of younger patients with diabetes:
When I trained in paediatrics in the 1980s, in a major children's hospital in Sydney, we never saw a child with type 2 diabetes. Now over 10 per cent of children in New South Wales under the age of 16 who have diabetes have type 2 diabetes. We're certainly seeing at my hospital and at others children who are yet to enter high school who have type 2 diabetes. Now, they will come from families with a very strong family history of type 2 diabetes as well, but we never saw it before. It was an old person's disease when I was growing up; now it's the stuff of which we need to train our endocrinologists, and ordinary general paediatricians like me need to be aware of that.
2.60Type 2 diabetes is typically more serious and aggressive in young people. Diabetes Australia noted that ‘the aggressive onset of diabetes-related complications at a much younger age is widely observed both in Australia and internationally.’
2.61While the Committee heard that Type 2 diabetes prevalence (being the total number of individuals who have the condition at a specific time) is increasing in Australia, evidence was also received stating that the overall incidence rate (being the number of individuals who develop the condition during a particular time period) is decreasing. Dr Alan Barclay, Health and Nutrition Consultant for the National Retail Association, noted a decrease in the incidence of Type 2 diabetes over the past ten to 15 years, and suggested that this ‘doesn’t seem to be particularly well known.’
2.62The National Retail Association’s submission also cited research supporting that the incidence rate of Type 2 diabetes in Australia has been decreasing over recent decades, except for a small increase between 2020 and 2021, which may be attributable to COVID-19 lockdowns. The AIHW noted that COVID-19 lockdowns had a negative impact on several lifestyle factors including healthy dietary patterns and physical activity.
2.63In appearing before the Committee, Professor Shaw explained that incidence is the best metric of the risk of the general population developing Type 2 diabetes and elaborated:
The incidence of at least clinically diagnosed type 2 diabetes has actually been coming down in Australia and in a number of other high-income countries… That doesn't mean the numbers of people with diabetes aren't still going up. In terms of the burden of care, the burden of care is still rising. But it also does indicate some suggestion at least that some of the things that many countries have done over the last 10 or 20 years might have had some benefit. It's modest… But it does, perhaps, indicate that some [of] the things that we've been doing have at least been moving in the right direction.
2.64An increase in gestational diabetes has also been recorded in Australia. According to the Australian Diabetes in Pregnancy Society (ADIPS), approximately one in five pregnancies in Australia are affected by diabetes. This statistic includes those diagnosed with gestational diabetes, and a small proportion of women (around 1–2 per cent) who have another form of diabetes prior to pregnancy.
2.65Diabetes Australia and the ADIPS both identified gestational diabetes as the ‘fastest growing type of diabetes in Australia’ and reported that the number of women diagnosed with this condition each year has more than doubled in comparison to the previous decade.
2.66Multiple explanations for the increase in gestational diabetes were offered throughout the inquiry. These included increasing maternal age in pregnancy, increasing body mass index (BMI), earlier age of diabetes onset, higher proportions of mothers who are at a higher risk of diabetes due to their ethnicity, and a change in the diagnostic criteria for gestational diabetes.
2.67According to Maternal Health Matters, changes to the definitions of and thresholds for gestational diabetes is the key reason driving the increase in diagnoses. Professor Jenny Doust, a general practitioner and professor of clinical epidemiology, told the Committee that since the new definitions for gestational diabetes were introduced, around 25,000 additional Australian women each year are being diagnosed with the condition. Professor Doust called for an independent review of the way that gestational diabetes is diagnosed in Australia, and further noted that the changes to the gestational diabetes diagnosis have not been accepted in the United States, New Zealand or the United Kingdom, and were not endorsed by the RACGP.
2.68Professor Shaw also reiterated the issue with changing diagnostic parameters:
…there certainly has been an increase in gestational diabetes. I have to say that a significant component, but certainly not all of it, has been a change in diagnostic criteria, which has [meant] that women who five years ago would have been told that they don’t have gestational diabetes are now told they do have it. That's not to say that's a good or bad thing, but it's a significant component of the increase in the numbers.
2.69Gestational diabetes can have an adverse effect on both the mother and the child. The Committee heard that even though gestational diabetes generally resolves after birth, women who develop the condition during pregnancy are at a higher risk for future health issues beyond their pregnancy. For instance, the ADIPS submitted that gestational diabetes increases the risk of Type 2 diabetes ten-fold, and the risk of experiencing a cardiovascular event in the future two-fold.
2.70The CDOER further noted that ‘diabetes and obesity in the mother during pregnancy increase the risk of obesity and diabetes in the offspring’, which can stimulate a ‘cycle of disadvantage.’ Diabetes Australia similarly characterised diabetes as an intergenerational condition: children born to mothers with gestational diabetes are ‘seven times more likely to develop type 2 diabetes later in life.’
2.71The Committee received a limited amount of evidence about trends or future forecasts for other forms of diabetes, beyond Type 1 diabetes, Type 2 diabetes, and gestational diabetes. It is notable, however, that NDSS data shows that the prevalence of other forms of diabetes has increased by 110 per cent in Australia over the past decade.
2.72In her submission to the inquiry, Dr Kumar noted that among people with cystic fibrosis, both the prevalence and incidence of cystic fibrosis-related diabetes increase with age. She explained that the life expectancy for people with cystic fibrosis was expected to increase, which by extension suggested that more people within this cohort would likely develop cystic fibrosis-related diabetes in the future.
Current levels of overweight and obesity
2.73Many contributors to the inquiry expressed the opinion that, as with diabetes, Australia is experiencing an obesity epidemic. Also similar to diabetes, obesity rates are higher among communities that have greater socio-economic disadvantage.
2.74According to the National Obesity Strategy 2022–32, approximately 14 million Australians are currently either overweight or obese. The Department of Health and Aged Care detailed that, as of 2017–18, approximately 67 per cent of Australian adults aged 18 years and older – and 25 per cent of children and adolescents aged between 2 to 17 – were either overweight or obese. Of the Australian adult population, 31.3 per cent of people were specifically living with obesity.
Trends and future forecasts for overweight and obesity
2.75Obesity is a significant and growing issue globally. The World Obesity Foundation predicts that, if current trends continue, by 2035 more than half of the world’s population will be either overweight or obese. Childhood obesity is rising even faster, and the number of children living with obesity may double between 2020 and 2035.
2.76Australia is a significant contributor to the global rise in obesity. According to the Organisation for Economic Co-operation and Development (OECD), Australia ranks the fifth highest for obesity rates among OECD countries.
2.77Looking at long-term trends, the Australian Medical Association noted that:
Rates of obesity [not including overweight] in Australian adults have been steadily increasing for at least 25 years (from 19% in 1995 to 31% in 2018). Among children (aged 5-17), there has also been an upward trend (from 5% in 1995 to 8% in 2018). It is estimated that a third (33%) of the projected adult population will be obese by 2025.
2.78In addition to the increase in the rates of obesity, the severity of the condition has also changed. Pharmaceutical company Novo Nordisk submitted that:
The highest relative growth in numbers of people with obesity during the last decade has been in Class III category (BMI of 40 or higher). According to some experts, Class III is the most expensive class of obesity to treat and one where the individual is at highest risk for complications.
2.79Sydney Low Carb Specialists expressed particular concern about the increasing rate of childhood obesity in Australia, because children who are overweight or obese tend to struggle with their weight into adulthood.
2.80The Committee received evidence suggesting that, if the current trend continues, more than 40 per cent of the Australian population is likely to be living with obesity in the next 10 years, which will have direct impact on the rates of Type 2 diabetes.
Impact of diabetes
2.81The impact of diabetes is enormous for those suffering with the disease, and their families. With a significant number of Australians living with diabetes, there is also an acute impact on the country’s health system and the economy.
Health system impact
2.82Several submissions asserted that the number of Australians currently living with diabetes created substantial pressure on the health system. As Diabetes Australia explained, diabetes is a ‘serious chronic condition that can cause debilitating and costly complications.’
2.83Diabetes-related complications can include blindness, kidney disease, heart conditions, stroke, lower limb amputations, and many more health conditions. The Alfred Alliance in Diabetes’ submission elaborated that diabetes is:
- the leading cause of kidney failure across the whole population
- among the leading causes of vision loss among working-age adults
- responsible for more than 50 per cent of all lower limb amputations
- a major risk factor for most manifestations of cardiovascular disease.
- AIHW data indicates that diabetes leads to approximately 17,477 deaths per year, and is associated with around 10.5 per cent of all deaths. Diabetes Australia highlighted that the number of diabetes-related deaths increased by 73 per cent between 2000 and 2020.
- Primary care plays a key role in helping individuals living with diabetes manage the condition, including any diabetes-related complications that arise. The RACGP submitted that in 2019–20, out of all the general practitioner appointments with patients, approximately 12 per cent were with patients with Type 2 diabetes (alone), one per cent were with patients with Type 1 diabetes, and one per cent were with patients with gestational diabetes.
- Presentations at emergency departments and hospitalisations offer additional insight into the impact of diabetes on Australia’s health system. According to the Department of Health and Aged Care, in 2020–21 there were almost 1.3 million hospitalisations associated with diabetes, representing approximately ten per cent of total hospitalisations in Australia. Approximately five per cent of these patients had diabetes recorded as the principal diagnosis (i.e. the diagnosis largely responsible for the hospitalisation).
- The Australian Centre for Accelerating Diabetes Innovations (ACADI) highlighted an Australian study suggesting that around 30 to 40 per cent of people admitted to hospital had some type of diabetes. Other sources suggest that around 23 or 25 per cent of hospital inpatients will have diabetes.
- The complexity of diabetes-related hospital admissions, Diabetes Australia explained, ‘means that the average length of hospitalisation is significantly longer for a person living with diabetes than in a person without diabetes.’ The Ingham Institute agreed with this assessment, and cited evidence showing that on average patients living with diabetes stay in the hospital about 2.6 days longer than patients without diabetes.
- Attendances at emergency departments indicate that diabetes accounts for ‘around 19,000 emergency department presentations.’ As the Australian College of Nurse Practitioners explained:
The healthcare system finds itself grappling with the challenge of managing not only the rise of diabetes-related hospital admissions, but also the substantial costs of treating the inherent complications.
Impact on Residential Aged Care and the National Disability Insurance Scheme
2.90The growing number of Australians living with diabetes will also impact other government services, including residential aged-care facilities and the National Disability Insurance Scheme (NDIS). Diabetes is more common among older Australians: in 2021, almost one in five adults aged between 80 to 84 were living with diabetes. The number of Australians aged 85 years and over will double by around 2050, which will result in a ‘significant increase in the number of people living with diabetes in aged care.’
2.91Diabetes poses additional challenges to the residential aged care system, as many aged care residents living with diabetes will require specific diabetes management support and care, such as assistance with blood glucose monitoring, help administering insulin or other medications, and special dietary requirements.
2.92The NDIS is another area likely to be impacted by the growing prevalence of diabetes in Australia, since ‘people with diabetes are twice as likely to live with a disability than people without diabetes.’ Mrs Catharina Felton, who has been diagnosed with insulin-dependent Type 2 diabetes, submitted that if she were unable to control and manage her condition effectively (and experienced complications leading to a disability), it could lead to ‘potential reliance on the NDIS.’
Financial impact of diabetes
2.93The overall financial impact of diabetes can be divided between direct and indirect costs. Direct costs are costs borne by the health sector for providing patient care (such as hospitalisation or medication); indirect costs encompass all other affected areas (for example, loss of productivity due to illness or premature death).
2.94Diabetes Australia estimated that the total annual cost of diabetes in Australia is $17.6 billion. Ms Cain from Diabetes Australia further noted that, based on more up-to-date modelling, this estimate was currently approximately $17.9 billion. The Grattan Institute provided an even higher estimate, suggesting that the total cost of diabetes to Australia could be $20.4 billion each year.
2.95The Australian Diabetes Society, which is the peak national medical and scientific body in Australia for diabetes, submitted that ‘it is unclear what the direct and indirect costs of diabetes are to the Australian economy.’ Consequently, the organisation recommended that a comprehensive health economic analysis of the direct and indirect costs was needed.
Direct costs of diabetes
2.96The Committee received substantial evidence about the direct costs of diabetes to Australia’s health care system. For instance, Medtronic, a medical device company, suggested that:
In Australia the average direct medical cost of a person with diabetes is estimated to be twice the direct medical cost of patients without diabetes (annual healthcare costs of A$3,005 per person with known diabetes and A$1,446 for those without diabetes).
2.97The costs to the health system are higher for people with diabetes-related complications. An Australian study cited by Diabetes Australia found that the direct cost of supporting a person living with diabetes more than doubles once complications develop ($9,600 per annum for people living with diabetes-related complications, compared to $3,500 for a person without complications).
2.98The CDOER also asserted that ‘diabetes becomes expensive because of its complications.’ The Baker Heart and Diabetes Institute submitted that cardiovascular disease, which includes coronary heart disease, stroke and peripheral arterial disease, was responsible for most of the financial costs related to diabetes.
2.99As another example, the CDOER noted that preventable blindness, which was commonly caused by diabetes, cost Australia approximately $2 billion annually. In part, this reflects the fact that most people who become blind later in life never return to paid employment.
2.100Diabetes is also the most common cause of end-stage kidney failure in Australia (also known as renal failure), which costs the country $2.6 billion annually. Organ damage is expensive not only to the health system (owing to the substantial costs of dialysis and kidney transplantation), but indeed the economy more broadly. The CDOER explained that many people with end-stage kidney failure do not resume paid employment, and that most patients on haemodialysis (an ongoing process through which a machine cleans a patient’s blood multiple times each week) could not work full-time.
2.101The Endocrinology Section of the Department of Medicine at Alice Springs Hospital also outlined the costs associated with diabetes related complications, and emphasised that dialysis treatment for a single patient cost over $100,000 per annum. With approximately 450 people on dialysis in Central Australia currently, this equates to at least $45 million spent on dialysis alone.
2.102The Menzies School of Health Research has estimated that the cumulative cost of dialysis for patients with end-stage kidney disease in Central Australia up to and including 2025 was approximately $264–342 million, and that if 20 per cent of new end-stage kidney disease cases could be prevented, it would result in a saving of about $302 million.
2.103Diabetes-related foot disease is another common complication. As Diabetes Feet Australia, the peak national clinical and research body for diabetes-related foot health and disease, explained: ‘People with diabetes are at risk of nerve damage causing the loss of protective sensation of the feet, reduced blood flow to the feet, skin ulceration, infection and lower limb amputation.’ Diabetes Feet Australia estimated that the cost to Australia of diabetes-related foot disease as of 2018 was about $1.6 billion, representing around 1 to 1.5 per cent of the Australian health budget.
2.104In its discussion of direct costs of diabetes to Australia’s health system, the Department of Health and Aged Care stated that for the financial year 2019–20, around $3.1 billion of expenditure in the Australian health system was attributed to diabetes. More recent AIHW data indicates that this cost increased to $3.4 billion in the year 2020-21, which means that 2.3 per cent of Australia’s total disease expenditure is spent on diabetes.
2.105According to the AIHW, this $3.4 billion Australian healthcare system expenditure on diabetes can be broken down into expenditure on specific forms of diabetes as follows:
- $373 million was attributed to Type 1 diabetes
- $2 billion was attributed to Type 2 diabetes
- $72 million was attributed to gestational diabetes
- $668 million was attributed to other or unknown diabetes.
The Committee acknowledges that the Department of Health and Aged Care advised caution when interpreting the above breakdown of expenditure by diabetes type, given the high amount allocated to ‘other/unknown’ diabetes.
2.106Costs of diabetes can also be ascertained by examining at areas of expenditure. AIHW advised that the total $3.4 billion spent on diabetes comprises:
- $953 million on the Pharmaceutical Benefits Scheme
- $750 million on public hospital admissions
- $555 million on dental services
- $377 million on general practitioner services
- $242 million on pathology
- $90 million on private hospital services
- $88 million on specialist services
- $58 million on allied health and other services
- $19 million on public hospital emergency departments
- $3 million on medical imaging.
- The Committee also heard that in addition to these costs, ‘a significant proportion of spending on private hospital care is directly attributable to diabetes or closely related.’
- Throughout the inquiry it was repeatedly impressed upon the Committee that diabetes-related health system costs are likely to increase in the future. Australia’s aging population is a major contributing factor, with Diabetes Australia noting that the ‘costs of treating diabetes increase as people age with more than 54% of costs relating to people aged 60 and over.’
- NSW Health also expected diabetes-related health system costs to rise, and informed the Committee that total NSW hospital inpatient costs for diabetes were forecast to increase from $1.8 billion annually in 2019–20 to $2.55 billion in 2028–29. NSW Health added that this represented a projected total of $21.7 billion over a decade, and ‘is equivalent to more than 2.9 million episodes of care, 4.6 million NWAU (National Weighted Activity Unit) and 18 million bed days used.’
- Over the past two decades the Australian healthcare system costs related to all types of diabetes have risen:
- direct healthcare costs have increased by 289 per cent
- hospital costs have increased by 308 per cent
- Pharmaceutical Benefits Scheme costs have increased by 282 per cent.
- The RACP emphasised the potential cost benefits from reducing the cases of Type 2 diabetes in Australia, noting that modelling has estimated that a ‘10% reduction in the rate of type 2 diabetes in Australia would result in a gain of GDP [Gross Domestic Product] $532 million over the next 10 years.’
Indirect costs of diabetes
2.112The Committee heard that the indirect costs of diabetes are significant and include lost wages and superannuation, lost productivity, travel costs to receive treatment, the costs of carers, the cost of aids, work modifications, and additional welfare payments.
2.113The RACP informed the Committee that the indirect costs associated with both diabetes and obesity are borne by different groups:
…patients and carers bear the direct cost of lost income and disease, the economy faces the cost of lost productivity and governments experience lost revenue and higher costs for income support payments. These national costs are in addition to the Australian Government’s direct healthcare costs.
2.114Further elaborating on the indirect cost of diabetes, Diabetes Victoria noted that these arise from ‘decreased productivity, work absences, early retirement, [and] premature death,’ and were estimated to be $14 billion per year.
2.115The Committee received a number of submissions that referenced the particular economic impacts that flow from working-age adults living with diabetes. For example, the Primary Care Diabetes Society of Australia noted that when people living with diabetes under the age of 55 leave the workforce because of difficulties managing their condition alongside their job, this has subsequent effects on taxation, welfare support and hospital usage. These financial impacts are in addition to the impacts on affected individuals and their families, which may include the possible negative psychological impact of leaving the workforce earlier than intended.
2.116The George Institute for Global Health estimated that by 2030 almost five per cent of Australians aged 45–64 will have left the workforce due to diabetes – up from 4.2 per cent in 2010. The Institute further stated that in 2012, ‘the estimated cost of lost labour-force participation in Australia due to diabetes was $384 million, with resultant extra welfare payments of $4 million and lost tax revenue of $56 million.’
2.117The Committee was informed that the Juvenile Diabetes Research Foundation (JDRF) Australia has undertaken an economic assessment of the costs of Type 1 diabetes specifically. JDRF Australia’s analysis identified that Type 1 diabetes costs Australia approximately $2.9 billion annually – of which, approximately 20 per cent was borne by the Australian Government. Diabetes Australia emphasised that diabetes-related complications significantly increased the costs associated with Type 1 diabetes: the lifetime cost is $738,000 when complications develop, compared to $143,000 for an individual with Type 1 diabetes without diabetes-related complications.
2.118As one illustration of the indirect economic costs of Type 1 diabetes, the Type 1 Foundation, a not-for-profit charity that supports people living in Australia with Type 1 diabetes, surveyed 2,900 people in Australia either living with, caring for, or in a relationship with a person living with Type 1 diabetes. This survey found that 81 per cent of parents had their ability to work impacted by Type 1 diabetes, and that 70 per cent of parents with school-aged children with Type 1 diabetes had to either cease full-time employment, change jobs, or start working part-time.
2.119Factors like reduced workforce participation, absenteeism, and underemployment contribute to lower productivity. According to a 2014 study by Deloitte Access Economics, diabetes was estimated to cost Australia approximately $5.63 billion annually in lost productivity.
Committee comment
2.120The Committee acknowledges that diabetes is a complex condition, and that questions relating to its cause, risk factors, and diagnosis are a subject of ongoing scientific debate. Equally, the Committee recognises that obesity is caused by multiple interrelated factors, and that while there is consensus regarding the link between obesity and diabetes, the nuances of this link are still not fully understood.
2.121The statistics presented in this chapter clearly show that diabetes is a major problem both in Australia and around the world. The Committee is particularly concerned about the growing number of Australians living with Type 2 diabetes, and the potentially high number of people with undiagnosed Type 2 diabetes. Evidence pointing to a rise of Type 2 diabetes among children is particularly distressing. The Committee also acknowledges the potential intergenerational effect of Type 2 diabetes and gestational diabetes. There is a real possibility that some Australian children will have worse life expectancies than their parents due to diabetes.
2.122In addition to the impact that diabetes has on individuals and their families, the Committee is also deeply concerned about the impacts of diabetes on Australia’s health system, particularly considering that the overall number of Australians living with diabetes is increasing.
2.123Beyond the health system, the Committee agrees that if it is not prevented and managed, diabetes will likely lead to significant cross-portfolio costs in areas such as the NDIS, reduced income tax, and lost productivity. Overall, diabetes could have a serious adverse impact on Australia’s economy.
2.124There is no doubt that diabetes is a major public health challenge. Efforts to address the increasing incidence and prevalence of the disease are critical. Serious intervention is needed now if the cost of diabetes in Australia is to be contained.
2.125The Committee recommends that the Australian Government undertakes a comprehensive economic analysis of the direct and indirect cost of all forms of diabetes mellitus in Australia.
2.126Diabetes has a substantial impact on both the national health system and economy. Current data, however, offers only a fragmented and piecemeal picture of this impact. A comprehensive and systematic analysis of the direct and indirect cost of diabetes will enable the development of more cost-effective measures to deal with the impact of diabetes.