What are non-communicable diseases?

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What are non-communicable diseases?
What are the main types of non-communicable diseases?
What is the forecast for non-communicable disease?
What is the economic burden of non-communicable disease?
Evidence-based recommendations for preventing non-communicable disease
Conclusions
References



What are non-communicable diseases?

Non-communicable diseases (NCDs) are non-infectious diseases and are by far the leading cause of death globally, making up around 63% of all deaths annually (Alwan), with most deaths from cardiovascular diseasescancersrespiratory diseases, and diabetes. Risk factors for most non-communicable diseases include tobacco use, unhealthy diet, insufficient physical activity, and the harmful use of alcohol, which lead to high blood pressure, overweight and obesity, hyperglycemia and hyperlipidemia. The following table sets out the key points in more detail:

Area Details
Definition of non-communicable diseases By definition, non-communicable diseases are the category of diseases or conditions that are non-infectious. Consequently, they are not transmissible between individuals. In practice, the term non-communicable disease is often used more loosely and synonymously with informal expressions such as “diseases of affluence” or “diseases of civilization”. Such expressions are used because is widely believed that these diseases afflict the developed nations to a greater extent than infectious diseases, which are sometimes called “diseases of poverty”. However, this is not in fact the case and in fact ~29 million of the 36 million of deaths attributable to non-communicable disease occurred in low- and middle-income countries (Alwan).
Lifestyle risk factors for non-communicable diseases It is thought that a large majority of non-communicable diseases are preventable through changes to either lifestyle or to the environment through cost-effective and feasible interventions (Alwan). The most important risk factors for this group of diseases have been identified as tobacco use, unhealthy diet, insufficient physical activity, and the harmful use of alcohol. Of the ~36 million annual deaths attributable to non-communicable disease, an estimated 6 million are thought to be directly attributable to tobacco use, 3.2 million to physical inactivity (<30 minutes of moderate activity or <20 minutes of vigorous activity, 3 times per week), 2.3 million to alcohol abuse, and 1.7 million to poor diet (Alwan). The indirect effects are difficult to estimate.
Metabolic and physiological risk factors for non-communicable diseases It is thought that the key lifestyle and environmental risk factors lead to four key metabolic and/or physiological changes: high blood pressure, overweight and obesity, hyperglycemia (a precursor to type II diabetes and the metabolic syndrome) and hyperlipidemia (which includes hypercholesterolemia). The World Health Organization (WHO) have calculated that high blood pressure directly accounts for 7.5 million deaths annually, while overweight and obesity account for 2.8 million, and hyperlipidemia 2.6 million. The WHO assess that high blood pressure (as defined by a systolic blood pressure of ≥140 mmHg and/or diastolic blood pressure of ≥90 mmHg, or using medication to lower blood pressure) is the most important risk factor of these four (Alwan).
The biggest causes of mortality By far the most significant contributor to the total death toll from non-communicable diseases is the category of disease known as cardiovascular diseases, accounting for ~17 million of the 36 million deaths in 2008. After that, the top three offenders are cancers (7.6 million), respiratory diseases (4.2 million) and diabetes (1.3 million).

Non-communicable diseases are non-infectious diseases. Preventable non-communicable diseases are often called “diseases of affluence” but in fact most deaths attributable to non-communicable disease occur in low- and middle-income countries. The most important risk factors such diseases are: tobacco use, unhealthy diet, insufficient physical activity, and the harmful use of alcohol, which lead to high blood pressure, overweight and obesity, hyperglycemia and hyperlipidemia. The non-communicable diseases that are the biggest causes of mortality are cardiovascular diseases, cancers, respiratory diseases, and diabetes.

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What are the main types of non-communicable diseases?

The following table sets out some of the more common non-communicable diseases that can be prevented through changes to either lifestyle risk factors or to the environment.

Disease Description
Type II diabetes Type II diabetes is a condition that is characterized by chronically elevated blood glucose (hyperglycemia) following from an inadequate insulin secretion relative to needs. The pathophysiology of the disease results from a combination of impaired insulin secretion due to insulin resistance in the liver and beta-cell damage and insulin resistance in the muscle tissue (Bock et al. and Defronzo). The development of type II diabetes seems to be closely related with the development of obesity, coinciding with a genetic predisposition for beta cell dysfunction (Kahn, 2003).
Metabolic syndrome Metabolic syndrome is a term that refers to a cluster of metabolic risk factors that put an individual at an increased risk for cardiovascular disease and type II diabetes. The most widely accepted risk factors that define metabolic syndrome are dyslipidaemia, elevated blood pressure and elevated plasma glucose. Metabolic syndrome is often referred to as an entity having a single cause. However, various researchers have more recently suggested that it truly is a syndrome, characterized by a grouping of cardiovascular risk factors and probably having more than one cause (Grundy et al., 2005). Although the various risk factors comprising metabolic syndrome increase the risk of developing CVD and increase all-cause mortality, the full syndrome is associated with a risk that is greater than the risk of each separate factor (Gami et al., 2007).
Obesity and overweight Obesity arises from an individual being in a chronically positive energy balance. This is a state in which energy intake is greater than energy expenditure. However, the condition is recognized to be a multifaceted issue that includes genetic, environmental and cultural influences and the rising standard of living in the developed world. Obesity and Overweight are often defined by reference to Body Mass Index (BMI), where Overweight is defined as a BMI of >25kg/m2 and Obesity is defined as a BMI of >30kg/m2.
Atrial Fibrillation Atrial fibrillation is a common form of cardiac arrhythmia that often leads to an increased and/or irregular heartbeat and/or low blood pressure. This altered heart rhythm makes the heart less efficient at moving blood around the body. It is thought to arise as a result of abnormal electrical impulses firing in the atria, which override the natural pacemaker of the heart and consequently lead to an irregular pulse rate. The general symptoms of atrial fibrillation include tiredness, breathlessness, dizziness and chest pain (angina). While atrial fibrillation occurs commonly following cardiac surgery, the exact causes and underlying pathology are poorly understood.
Hypercholesterolemia Hypercholesterolemia is the presence of elevated levels of cholesterol in the blood. It is a sub-category of hyperlipoproteinemia, which is the presence of elevated levels of lipoproteins (combined fat and protein molecules) in the blood, which is itself a sub-category of hyperlipidemia, or the presence of elevated levels of lipids (fats) in the blood (Durrington). Cholesterol is transported in the blood within the lipoproteins, which are molecules that have a globular shape and are a combination of lipid (fat) and protein. The center of a lipoprotein is made up of lipid, primarily triacylglycerol and cholesteryl ester, while the outer membrane is made up of phospholipids, a small amount of free cholesterol and proteins called apolipoproteins (Biggerstaff and Wooten).
Hypertension Hypertension is defined a blood pressure above a certain level (i.e. hypertension is high or elevated blood pressure). Blood pressure is typically quoted in two numbers: systolic and diastolic. Systolic blood pressure is the pressure in the artery when the heart is in systole (i.e. when the heart is contracting) and diastolic blood pressure is the pressure in an artery when the heart is in diastole (i.e. when the heart is relaxed). Therefore, systolic blood pressure is much higher than diastolic blood pressure. High blood pressure or hypertension is widely regarded as a very significant risk factor for cardiovascular disease in general and coronary artery disease in particular. High blood pressure is defined by a systolic blood pressure of ≥140 mmHg and/or diastolic blood pressure of ≥90 mmHg, or using medication to lower blood pressure.
Coronary artery disease Coronary artery disease has various different names, including coronary heart disease and ischemic or atherosclerotic heart disease. Coronary artery disease progresses through the build-up of plaque within the arteries of the heart, a process called atherosclerosis. This build-up of plaque leads to narrowing of the coronary arteries and reduced blood-flow to the heart itself. However, in the absence of close medical examination, there are often few symptoms coronary artery disease progressing in otherwise healthy individuals. Indeed, the earliest symptoms may include angina (i.e. chest pains), reduced exercise tolerance and even heart attacks. Coronary artery disease is widely accepted to be the most common cause of death worldwide but varies widely between geographical locations, with the highest rates being found in the lower income countries and the lowest rates being observed in the higher income countries (Finegold et al.).
Peripheral arterial disease Peripheral arterial disease is the narrowing of the arteries in the legs as a result of atherosclerosis (Hirsch et al.) and it increases the risk of short-term cardiovascular events. It is most commonly measured using the ankle-brachial blood pressure index, which is a measurement of segmental blood pressure. The earliest and most frequent symptom of peripheral arterial disease is intermittent claudication, or pain in the leg muscles when walking. If peripheral arterial disease is allowed to continue unhindered, similar pains may develop in the legs at rest. While peripheral arterial disease is not as widely monitored as other aspects of cardiovascular disease, it is a serious health risk. Individuals with peripheral arterial disease display a 3.3 times greater rate of all-cause mortality (Criqui et al.), a 5.9 times greater rate of cardiovascular disease mortality and a 6.6 times greater rate of coronary heart disease mortality.
Stroke A stroke is the rapid loss of neurological function following a failure of the blood flow to the brain. This failure of the blood flow can result either from a blood flow restriction (ischemia) following an arterial blockage or from a hemorrhage following the rupture of a blood vessel. Strokes can lead to permanent damage as a result of infarction (tissue death). Strokes are commonly categorized as either ischemic and hemorrhagic in type. It is thought that the large majority of strokes are of the ischemic category. Ischemic strokes are similar in concept to heart attacks, which involve the failure of blood supply to the heart rather than to the brain. Common symptoms of stroke include the inability to move the legs or arms on one side of the body, an inability to understand speech, or a loss of vision.
Transient ischemic attack A transient ischemic attack is very similar to an ischemic stroke in that involves neurological dysfunction following a failure of the blood flow to the brain (ischemia). However, transient ischemic attacks do not involve infarction (tissue death) and symptoms typically resolve in a very short period of time. Transient ischemic attacks present very similar symptoms to strokes, including the inability to move the legs or arms on one side of the body, an inability to understand speech, and a loss of vision. Transient ischemic attacks are sometimes referred to as mini-strokes in the lay press.
Chronic obstructive pulmonary disease ‪"Chronic Obstructive Pulmonary Disease (COPD) is characterized by persistently limited airflow and is associated with an enhanced chronic inflammatory response in the airways and lungs to noxious particles or gases (Pauwels et al.). The chronic inflammatory response may lead to tissue destruction in the lungs (leading to emphysema) and disrupt normal repair (leading to fibrosis of the small airways). Such changes may increase the limitations to airflow limitation thereby increasing the sensation of breathlessness."
Chronic kidney disease Chronic kidney disease (CKD) is defined as occurring where an individual has either kidney damage for >3 months, as denoted by structural or functional abnormalities, or has a glomerular filtration rate of <60 ml/min per 1.73m2 or a urinary albumin-to-creatinine ratio >30mg/g for >3 months (Levey et al.).
Parkinson's Parkinson’s is a chronic neurodegenerative condition. Untreated, it generally leads to progressive disability and reduced health-related quality of life. It is characterized by slowness of movement (also called bradykinesia), postural instability, tremors, stiffness of the limbs and trunk and reduced muscular strength. The condition is thought to arise from a chemical imbalance in the brain (in relation to dopamine), which causes a reduction in the excitatory drive of the motor cortex and therefore reduced neuromuscular performance.
Alzheimer's Alzheimer’s disease is the most common form of dementia afflicting elderly people but it is difficult to diagnose clinically. However, the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association have provided diagnostic guidance, which were updated most recently in 2011. These organizations specify that the criteria for diagnosing an individual with Alzheimer’s disease first requires a diagnosis of general dementia, which is defined as: having a condition which interferes with the ability to function at work or during usual activities, which represents a decline from previous levels of function, which is not explained by delirium or major psychiatric disorder, and which can be defined as a cognitive impairment (involving either impaired memory, reasoning, language or visual-spatial abilities or changes in personality) (McKhann et al.).
Dementia Dementia afflicts a great number of elderly people but it is difficult to diagnose clinically. However, the National Institute of Neurological and Communicative Disorders and Stroke and the Alzheimer’s Disease and Related Disorders Association have provided diagnostic guidance, which were updated most recently in 2011. They specify that general dementia is defined as: having a condition which interferes with the ability to function at work or during usual activities, which represents a decline from previous levels of function, which is not explained by delirium or major psychiatric disorder, and which can be defined as a cognitive impairment (involving either impaired memory, reasoning, language or visual-spatial abilities or changes in personality) (McKhann et al.).
Fibromyalgia Fibromyalgia, also called fibromyalgia syndrome, is a fairly common musculoskeletal disorder that is characterized by chronic widespread pain at a number of anatomical locations and a reduced pain threshold. Sufferers commonly complain of fatigue, depression, anxiety, sleep disturbances, headache, migraine, abdominal pain and increased urinary frequency. The exact cause of the condition is unknown.
Osteoporosis Osteoporosis is a disorder in which a loss of bone mass and strength leads to fractures. It most commonly occurs in post-menopausal women, in which estrogen deficiency likely has a key role. The concept of osteoporosis has changed markedly over the years. However, the current concept is that osteoporosis occurs along a continuum, in which multiple mechanisms are active, causing a loss of bone mass (typically measured as bone mineral density) and a deterioration in the microarchitecture of the bone structure, leading to a high incidence of fractures (Raisz).
Sarcopenia Sarcopenia is a syndrome involving low muscle mass and reduced muscle function, typically observed in the ageing individual. Sarcopenia usually involves a generalized loss of muscle rather than a localized loss of muscle or muscle group-specific loss of muscle. Moreover, it is thought that this loss of muscle follows primarily from disuse atrophy. Sarcopenia is a key problem in geriatrics and leads to an increased risk of several adverse health outcomes, including physical disability, poor health-related quality of life and increased mortality.

Preventable non-communicable diseases include: Type II diabetes, Metabolic syndrome, Obesity, Atrial Fibrillation, Hypercholesterolemia, Hypertension, Coronary artery disease, Peripheral arterial disease, Stroke and transient ischaemic attack, Chronic obstructive pulmonary disease, Cancer, Chronic kidney disease, Parkinson’s, Alzheimer’s, Dementia, Fibromyalgia, Osteoporosis and Sarcopenia.


What is the forecast for non-communicable disease?

Projections from the World Health Organization (WHO) have reported that annual global deaths from non-communicable disease will increase by 15% between 2010 and 2020, from 36 million to 44 million deaths per year, and by 44% between 2010 and 2030 from 36 million to 52 million deaths per year (Alwan). The WHO estimate that, between 2010 and 2020, the largest increase in annual global deaths from non-communicable disease will occur in Africa, South-East Asia and the Eastern Mediterranean, where they will increase by >20%, while no marked increases are expected in Europe (Alwan).

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What is the economic burden of non-communicable disease?

The economic burden of non-communicable diseases has been described in various countries by the World Health Organization (WHO). The speed of growth in the loss of national income for some of the developed countries is astonishing. The estimated losses in national income from heart disease, stroke and diabetes are presented below in 2005 and 2015 (Abegunde and Stanciole):

Country 2005 ($USD) 2005 (% of GDP) 2015 ($USD) 2015 (% of GDP)
China 18 billion 0.31% 13 billion 1.18%
Russian Federation 11 billion 1.13% 6.6 billion 5.34%
India 8.7 billion 0.35% 54 billion 1.27%
Brazil 2.7 billion 0.19% 9.3 billion 0.48%
UK 1.6 billion 0.10% 6.4 billion 0.32%
Pakistan 1.2 billion 0.30% 6.7 billion 1.02%
Canada 0.5 billion 0.07% 1.5 billion 0.15%
Nigeria 0.4 billion 0.23% 1.5 billion 0.65%
United Republic of Tanzania 0.1 billion 0.29% 0.5 billion 0.86%

Based on the analysis from the World Health Organization (WHO), the speed of growth in the loss of national income for some developed countries is astonishing. For example, the UK is forecast to increase its annual losses by 250% over the 10-year period from 2005 to 2015, when measured in absolute terms, or by 220% when measured relative to GDP.


Evidence-based recommendations for preventing non-communicable disease

The World Health Organization (WHO) have made the following evidence-based recommendations for the prevention of non-communicable diseases:

Recommendation Details
Reduce tobacco use The WHO have advised governments to monitor tobacco use and to implement tobacco-prevention policies. They recommend that governments should legislate to protect people from tobacco smoke in public places and workplaces. They recommend that public bodies should offer help to people who want to stop using tobacco. They recommend that people should be warned about the dangers of tobacco. They suggest implementing bans on tobacco advertising, promotion and sponsorship. Finally, they propose that taxes and prices should be increased in relation to tobacco products.
Improve unhealthy diets The WHO have advised governments to promote and support the exclusive use of breastfeeding for the first 6 months of life. They recommend the implementation of programmes to ensure optimal feeding for all infants and young children. They recommend that governments should produce a national policy and action plan on food and nutrition that includes reducing salt levels, eliminating industrially produced trans-fatty acids, decreasing saturated fats, and limiting free sugars.
Increase physical activity The WHO have advised governments to develop and implement national guidelines for physical activity. They recommend that governments carry out school-based programs and provide safe spaces for active play, support safe, active commuting by foot or by bicycle, and create space for recreational activity.
Reduce harmful use of alcohol The WHO do not provide specific guidance to governments regarding actions to be taken in respect of alcohol but they note that governments should be aware of the impact of harmful use of alcohol on health conditions, including cancers, liver and cardiovascular diseases, and injuries.

Based on these recommendations, the main purposes of healthcare workers in providing guidance to individuals in relation to improving their risk profile for non-communicable disease should be to reduce tobacco use, improve unhealthy diets, increase physical activity, and reduce the harmful use of alcohol.

[Tweet “↓ tobacco use, improve diet, ↑ physical activity, + ↓ alcohol intake @Exercise4NCDs”]


Conclusions

On the basis of these studies and reviews, the following conclusions might be drawn:

Area Conclusions
Basic facts about non-communicable disease Non-communicable diseases are non-infectious diseases. Preventable non-communicable diseases are often called “diseases of affluence” but in fact most deaths attributable to non-communicable disease occur in low- and middle-income countries. The most important risk factors such diseases are: tobacco use, unhealthy diet, insufficient physical activity, and the harmful use of alcohol, which lead to high blood pressure, overweight and obesity, hyperglycemia and hyperlipidemia. The non-communicable diseases that are the biggest causes of mortality are cardiovascular diseases, cancers, respiratory diseases, and diabetes.
The main types of non-communicable disease Preventable non-communicable diseases include: Type II diabetes, Metabolic syndrome, Obesity, Atrial Fibrillation, Hypercholesterolemia, Hypertension, Coronary artery disease, Peripheral arterial disease, Stroke and transient ischaemic attack, Chronic obstructive pulmonary disease, Cancer, Chronic kidney disease, Parkinson's, Alzheimer's, Dementia, Fibromyalgia, Osteoporosis and Sarcopenia.
The growing economic burden of non-communicable diseases The speed of growth in the loss of national income for some developed countries is astonishing. For example, the UK is forecast to increase its annual losses by 250% over the 10-year period from 2005 to 2015, when measured in absolute terms, or by 220% when measured relative to GDP.
Recommendations for preventing non-communicable diseases The main purposes of healthcare workers in providing guidance to individuals in relation to improving their risk profile for non-communicable disease should be to reduce tobacco use, improve unhealthy diets, increase physical activity, and reduce the harmful use of alcohol.

In summary, non-communicable diseases non-infectious diseases and are by far the leading cause of death globally, making up around 63% of all deaths annually. The main risk factors are tobacco use, unhealthy diet, insufficient physical activity, and the harmful use of alcohol, which lead to high blood pressure, overweight and obesity, hyperglycemia and hyperlipidemia. The economic burden of non-communicable diseases is serious and the speed of growth in the loss of national income for some developed countries is extremely high. It is recommended to reduce tobacco use, improve unhealthy diets, increase physical activity, and reduce the harmful use of alcohol.


References

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