Why do Indians get paunches and heart disease?

INTRODUCTION

2009-11-13T23:31:00.001Z

In the last three decades there has been a huge rise in the incidence of coronary heart disease (CHD) amongst South Asians, both those in the Indian Sub-Continent of India, Pakistan, Bangladesh and Sri Lanka, and those who have migrated to Western countries such as Britain, Canada and the USA. Until recently, the reasons behind this increase were poorly known.

Since the 1960s, doctors have begun to understand better some of the risks and causes of coronary heart disease in the original white population of Western countries. Some factors such as getting older, being male, and having a family history of heart disease are important but can't be changed. But we have also realised that other factors such as smoking, obesity, high cholesterol, high blood pressure and lack of exercise are relevant, and can be improved by medication or changes in lifestyle. Governments and other organisations have made efforts to reduce the risk through education and other public health measures. It is thought that these efforts are beginning to pay off, and rates of heart disease in the white population have started to fall.

Unfortunately, the same success has not been realised amongst the South Asian population, where heart disease continues to rise. We are now seeing friends and relatives affected with angina and heart attacks in their fifties, forties, and even thirties. Doctors have suggested all sorts of causes, for example the stress of moving to a new country or facing racism, a diet high in certain fats such as ghee (clarified butter), and a tendency to develop diabetes. I think it is fair to say that we simply don't know for sure why Asians seem more prone, and there probably isn’t a single reason. However, in the last few years we are beginning to develop more ideas as a result of new research.

One of the most promising theories to emerge is that South Asians are at risk because they have a greater tendency to put weight on around the middle (the belly and the chest), even though they might not be particularly heavy generally. This belly fat interferes with the functioning of insulin, a hormone that controls blood sugar. This increases the risk of developing diabetes and pre-diabetes (also called insulin-resistance) which can damage blood vessels and lead to heart disease.

In this book/blog I outline some of the causes and risks for coronary heart disease in South Asians and give you some practical advice on measures you can take to try to reduce your chances of developing heart problems in the future. The good news is that the same measures can also help to reduce the incidence of diabetes and stroke, bring down blood pressure and weight, and (perhaps surprisingly) slow the age-related decline in memory and potency, all contributing towards a longer, healthier life. I hope it will be of use and interest not only to readers of South Asian origin now living in the West, but also to people in the Indian Sub-continent.

Important information (disclaimer)
In this short text, I can only give general health information. I am unable to give any specific medical advice to individual readers, If you are ill, or suspect that you have any symptoms of heart disease such as chest pain, feeling faint, light-headed or short of breath, then you should consult your family doctor or emergency medical service. If you live in the UK, then NHS Direct is a very useful source of advice and information: visit www.nhsdirect.nhs.uk or telephone 0845 46 47.

What is coronary heart disease?
Our heart is a pump made of muscle, pushing blood constantly around the body. Like any other muscle, it needs a good supply of blood to function well. Blood is fed to the heart through blood vessels called the coronary arteries. With age, in practically everyone, the arteries become narrower and harder, and develop fat-filled bumps on the inside wall. These changes are commonly called ‘furring of the arteries’ and reduce blood flow to the heart.

Technically, the hardening process is called arteriosclerosis, and the formation of the bumps is called atherosclerosis. The medical term for the bump is plaque or atheroma.

Diagram of atherosclerosis

Angina and heart attack
Two common forms of coronary heart disease (CHD) are angina and heart attack (myocardial infarction or MI, or simply ‘coronary’). They are both caused by atherosclerosis (‘furring’) of the coronary arteries:

In angina, the narrowing of the arteries to the heart leads to a reduction in blood supply, particularly in situations where the heart needs more blood such as exercise or stress. The result is a sort of temporary cramp of the heart muscle, which is usually felt as chest pain or tightness, or as shortness of breath. The symptoms will usually pass by resting or by taking certain medications such as GTN (glyceryl trinitrate).

In a heart attack (more technically, a myocardial infarction) one of the plaques splits open. When the contents of the plaque come into contact with the blood, they cause the blood to clot, forming a plug that blocks the artery. This completely restricts the flow of blood to an area of the heart muscle and usually causes pain. This area of muscle will become permanently damaged if the clot does not move or dissolve quickly. The damaged muscle may prevent the heart from beating properly, which can result in an irregular heartbeat, breathlessness, heart failure or death.

In this book/blog, I will refer to coronary heart disease as CHD or simply 'heart disease'.

PREVALENCE, OR HOW BIG IS THE PROBLEM?
Traditionally in the rural areas of the Indian Sub-continent, rates of heart disease were relatively low. One explanation could be that other causes of ill health such as infection were more common.
In the last three decades there has been a huge increase in the rate of heart disease amongst South Asians, first noted in those moving to the West or to the cities of the Indian Sub-continent. The rate in rural areas in the Indian Sub-continent is half that of the cities, and a quarter that of South Asians living in the US.

Differences in prevalence and severity of heart disease
Depending on which study you look at CHD is 1 - 4 times as common in South Asians as it is in the White population. This obviously increases the risk of dying, but also results in more ill health and disability.

What is perhaps less obvious and well-known is that, statistically, a South Asian suffering a heart attack is more likely to die from it. South Asians undergoing ‘bypass operations’ (Coronary Artery Bypass Grafting, CABG) have twice the post-operative death rate of white people.

Also worrying is the fact that South Asians are affected by heart diesease prematurely, on average 5-10 years earlier than their White counterparts. One study calculated the average age of first heart attack in South Asians to be 50 as compared to 56 in a White European population.

Summary
Coronary heart disease has become more common in South Asians over the past three decades. The condition seems to strike earlier and more aggressively. In the next section I will discuss some of the possible explanations.

EXPLANATIONS FOR DIFFERENCES

2009-11-13T23:15:00.006Z

Until relatively recently, people generally had a particular picture in their minds of the kind of person prone to a heart attack. The image would be of a middle-aged man, usually a stressed executive, who would return home after a long day. He might unwind with two or three whiskies, followed by a rich meal, perhaps steak served with a cream-based sauce. He would then sit down in front of the TV with his cigarettes and liqueur.

The reality, of course, is somewhat different. While there is no doubt that smoking increases the risk of developing heart disease, it might be surprising to learn that, in general, rich executives suffer less heart disease than manual and clerical workers.

It is also perplexing that the French have a relatively high consumption of fat and alcohol, yet have one of the lowest rates of heart disease in Europe (‘The French Paradox’). Conversely, vegetarian teetotal Gujarati people in the UK have one of the highest rates (‘The Indian Paradox’).

Causes and risks

When a relative or friend has a heart attack, it is natural to wonder why they suffered. We might remark that they never smoked or that they weren’t particularly overweight. Unfortunately it is difficult to come up with one particular cause in one person. It is easier to discuss risk factors and associations in the general population.

It is also important to remember it takes many years for arteries to harden, with the very early stages starting in childhood. A person’s lifestyle 10-20 years ago might be more important in determining their risk of CHD than looking at what they get up to now.

So, what are the explanations for heart disease in South Asians and what can be done?

This subject can be divided by discussing the conventional risk factors that apply to both general and South Asian populations (such as blood pressure), and the particular factors that might explain why South Asians are especially vulnerable. Some factors, such as getting older or being born male are beyond control and so are called unmodifiable risks. Others are modifiable, the classic example being smoking.

Conventional risks

Age

The older you are, the greater your risk of heart disease. In almost everyone, the arteries gradually fur with age.

Being male

Generally men suffer more heart disease than women, although women do start to catch up after the menopause. It is thought that the female hormone, oestrogen, might protect by improving the cholesterol profile.

Family History

If one of your first-degree relatives (parent or sibling) has had heart disease you unfortunately have a 30-50% greater chance of developing the condition yourself, particularly if your relative was diagnosed under the age of 60. In the case of a second-degree relative (uncle, aunt or grandparent) the risk is also increased but not as much. The greater the number of family members affected the greater the risk.

It is therefore important to talk to your doctor if a close relative is diagnosed with heart attack or angina, especially under the age of 60. Ask to have your cholesterol profile, glucose, blood pressure, height, weight and waist measured, and then follow your doctor’s advice accordingly.

High blood pressure (or hypertension)

What is blood pressure?

Blood pressure (BP) refers to the pressure in the arteries coming away from the heart. Like height, blood pressure naturally varies from one individual to the next. Unfortunately, having a high BP does not convey the same advantage in life as being tall.

What is the problem with high blood pressure?

It can result in narrowing (arteriosclerosis) and hardening of the arteries and the small blood vessels in the heart, the brain and the kidneys. The narrowing of the vessels puts a greater strain on the heart which has to pump harder to compensate, so setting up a vicious cycle increasing the blood pressure further. Which is why it is so important to treat high blood pressure early.

One problem for doctors is that unless the blood pressure is very high, there are usually no symptoms. The patient can feel perfectly well and therefore be reluctant to take treatment.

What should my blood pressure be?

Patients and family often ask what is a normal blood pressure, and I usually answer that there is no such thing. It’s a bit like asking if there is a normal height.

Put simply, when you see a blood pressure reading written down (e.g. 120/80) the first figure is the highest pressure reached in the artery (the ‘systolic’). The second figure is the baseline pressure (the ‘diastolic’).

Studies involving millions of patients throughout the world have shown that the higher the blood pressure the greater the long term harm. The level where the benefits of treatment outweigh any risk depends on whether the patient has other risk factors such as diabetes or kidney disease. Recommendations often change in the light of new studies.

Currently in the UK we aim for a BP of less than 140/90 in the general population and 130/80 in diabetics with kidney disease.

What causes high blood pressure?

On the whole, high blood pressure is usually constitutional—a reflection of a person’s natural make-up, in which case it is called Essential Hypertension.

Lifestyle factors, such as taking too much salt or alcohol, being overweight or being inactive, can raise the blood pressure further. The South Asian diet is particularly high in salt.

Occasionally high blood pressure is caused by another condition such as a hormone imbalance, when it is called Secondary Hypertension.

Action points - top tips about blood pressure

Make sure you know your blood pressure. You can have it measured by asking your doctor, nurse or pharmacist. You can also measure it your self with an easy to use, electronic blood pressure monitor bought from a pharmacy or drug store. These have become cheaper in recent years. An arm monitor is generally more reliable than a wrist device. The British Hypertension Society has a list of approved machines on its website:

http://www.bhsoc.org/bp_monitors/automatic.stm

As blood pressure varies with stress and activity, you should rely on a single reading, but measure it at different times over a one month period to get an idea of the trend.

If your blood pressure is persistently above 130 systolic or 80 diastolic you should consult your doctor. If it is borderline, he or she may decide to observe your blood pressure more closely and give advice on ways to reduce the blood pressure without pills (see below). If the readings are higher, or if you have other risk factors for heart disease, you may also be prescribed medication.

Of course, if you are already on medication for blood pressure you should ensure you take your pills exactly as prescribed and follow your doctor's advice, even if you feel perfectly well.

Additional ways to lower your blood pressure

Unless you already have a slim waist (see below), lose weight by reducing your intake of saturated fat and highly refined carbohydrates and by taking more aerobic exercise (walking, cycling, jogging or swimming).
Don't have more than one or two small alcoholic drinks in one day. Although a little alcohol may reduce the risk of heart disease, larger amounts can raise blood pressure.
Don't consume more than 6g of salt (one teaspoon) a day. A little salt (sodium) is needed by the body for many of its functions, however a high salt intake raises blood pressure. South Asian diets often have much more salt than is healthy.

How to reduce your salt intake

Reduce the amount of salt you add to cooking. If you do so gradually you will not notice. Herbs and spices can be used instead to add flavour.
Limit your consumption of pickles, chutneys, processed and ready made foods which often have large amounts of 'hidden' salt. Home made chutneys do not require as much salt, as they can be made fresh and kept in the fridge.
Increase your consumption of vegetables and fruit. They contain the mineral potassium which in moderation helps to counteract the harmful effects of too much salt. Although bananas are rich in potassium, they contain a lot of sugar, so don't have more than one small or half a large banana a day.
Substitute water or fresh vegetable or fruit juice for carbonated drinks ('sodas'). But remember that as fruit juice is high in sugar, keep to 100 ml served neat or diluted with water. (Soda water is high in sodium, so if you want fizz use sparkling mineral water instead.)
I do not recommend salt substitutes which contain potassium. Not only are they expensive, they can raise potassium levels too quickly in comparison to fruit and vegetables.

Smoking

Although most people know that smoking is harmful, it is still important to emphasise that it is a major risk factor for a number of respiratory and circulatory illnesses. It increases the chance of developing coronary heart disease by damaging the delicate lining of the arteries, which leads to narrowing and furring. It also makes the blood stickier and more likely to clot.

Action on smoking

It almost goes without saying that if you do smoke you should try to give up, or at least reduce your consumption.

All sorts of help is available:

Books
Websites and phone lines (for example, in the UK you can get help and information through the NHS Smokefree website or the NHS Free Smoking Helpline: 0800 022 4 332)
Hypnosis
Nicotine replacement gums, patches and inhalators or newer medication such as bupropion (Zyban) and varenicline (Champix). Talk to your doctor or pharmacist for more information.
One method for lighter smokers is to delay your first cigarette by another half an hour each day. This helps to weaken the physical craving for nictotine.

Weight

Being overweight or obese

We know that carrying excess weight can increase the risk of a number of conditions, such as CHD, diabetes, hypertension and arthritis.

WHAT IS THE BMI?

The body mass index (BMI) is a measure of how heavy someone is for their height. It gives health professionals a way of identifying those people who are unhealthily over- or under-weight and might benefit from further advice and treatment.

The formula for BMI is:

BMI = Weight (in Kg) / Height (in metres) x Height (in metres)

or put another way:

Weight divided by the height squared (where the weight is in Kg and the height in metres)

If you don’t want to calculate it yourself, there are all sorts of tables and websites available that will do it for you. I have one on my website:

bowri.co.uk/BMI

For the general population, a "normal" BMI is between 19 and 25.

BMI under 19 classed as underweight. Being underweight can be as unhealthy as being very overweight
BMI 25-30 classed as overweight. Health risks start to rise.
BMI over 30 classed as clinically obese. Risk to health rises more rapidly.

More recently studies have shown that South Asians are at greater risk of diabetes and CHD from being even mildly overweight, through a tendency to develop Insulin-Resistance (which was briefly described in the introduction and will be covered in more detail below).

This is a really important development and one not yet widely known in the South Asian community. Until only recently, we generally thought that to be thin or skinny was a mark of poverty, and that a ‘healthy’ physique was one characterised by a smooth chubby face and a spare tyre hidden under a kurta, kameez or sari. In reality, one of the very best things we can do for our health is to remain slim.

The World Health Organisation (WHO) have subsequently revised the thresholds for ‘overweight’ and ‘obese’ in South Asians to 23 and 25 respectively.

WHO revised classification of BMI:

	White	Asian
Overweight	25	23
Obese	30	25

Weight distribution and Insulin Resistance – Apples and Pears

It is not just the total weight (or BMI) that is important—the distribution of fat in the body also has an effect on health. We know that even from an early age, South Asians tend to lay down excess fat around the trunk (the chest, back and tummy). We call this central obesity, and it gives the body an apple shape (some doctors call it truncal or visceral obesity).

In white people fat tends to be distributed more evenly, not just around the middle but also around the hips and in the arms and legs. This gives the body a pear shape.

The pancreas is a gland which sits just beneath and behind the stomach. It has a number of functions, one of which is to regulate blood sugar (or glucose) by releasing hormones called insulin and glucagon. A very high blood glucose (Diabetes) is dangerous because it damages and ages the delicate tissues in structures such as the eyes, nerves, feet, kidneys and blood vessels, with a process similar to the crystallizing or candying used to preserve fruit. Very low blood glucose causes brain damage and can sometimes even kill.

When you eat a meal containing any carbohydrate (starch or sugar), digestion results in a rise in blood glucose which triggers a release of insulin from the pancreas. The insulin ‘tells’ the fat cells, liver and muscles to take in glucose, so helping to regulate its level. If blood glucose falls too low, the pancreas releases glucagon, which tells the liver to produce glucose.

Abdominal fat is thought to increase the risk of CHD and diabetes by interfering with (or ‘resisting’) the action of insulin in regulating blood sugar (glucose), so-called Insulin Resistance. The pancreas tries to compensate by releasing more insulin. As insulin stimulates further growth of fat cells, a vicious cycle is set up which often leads to full diabetes developing decades later.High insulin levels are thought to promote the formation of atheroma and to increase blood pressure. Also, abdominal fat releases inflammatory chemicals called cytokines which damage the delicate endothelial lining of arteries.

Unfortunately, nothing in medicine is a simple as a Google search would have you believe, and the reality is much more intricate than the approximation I’ve presented here. One of the known unknowns (as Donald Rumsfeld would have said) is which bit comes first—is it the abdominal fat or the raised insulin, or are they both the byproduct of another mechanism for Insulin Resistance?

One theory, called the ‘thrifty gene’ theory or hypothesis, says that South Asians have evolved to lay down abdominal fat in times of abundance, in order to increase the chances of survival during the famines which were once so common on the Indian Sub-continent. These days there are no famines in the middle class suburbs of Delhi, Karachi or London, and our excess abdominal fat actually reduces life expectancy.

Waist circumference (WC)

Getting back to practical advice, for South Asians a waist circumference (WC) of more than 90 cm (35 inches) in men or 85 cm (33 ½ inches) in women increases the risk of coronary heart disease and diabetes.

In general white people can be 8 – 10 cm (3 – 4 inches) bigger around the waist before their health risk goes up.

Remember to measure the waist with a tape measure at the level of the umbilicus (tummy button) and not at the level of the waistband of an item of clothing. Don’t suck your tummy in when you do this!

Healthy waist circumference (WC) in S. Asians (WHO):

Men - 90 cm or 35 inches
Women - 85 cm or 33 ½ inches

Waist / Hip Ratio (WHR)

One way of determining whether you have an apple shape or a healthier pear shape is to calculate the Waist Hip Ratio (WHR), by dividing the waist circumference (at the umbilicus) by the hip measurement (use a tape measure around the widest part of the hips).

Lower Risk (Pears) :

WHR less than 0.85 for women
WHR less than 0.95 for men

Higher Risk (Apples) :

WHR greater than 0.85 for women
WHR greater than 0.95 for men

If you are apple-shaped, then you can reduce your risk by reducing your tummy through diet and aerobic exercise, but I’ll say more about that in the section on prevention below.

The metabolic syndrome

What is it?

A group of particular health risks seem to be linked:

Central obesity
High blood pressure
Increased blood fats (triglycerides)
Increased glucose

People who have one of these risks often have some of the others, and we say that they have ‘the Metabolic Syndrome’.

What causes it?

There are various possible causes such as age, genetics, being overweight or inactive. As you might guess, we think that South Asians are more prone, and the explanation might be insulin resistance. As many as one in four people may have it.

What does it do?

The Metabolic Syndrome increases the risk of damaging blood vessels and of developing a wide range of conditions:

Coronary heart disease
Diabetes
Hypertension (high blood pressure)
Gout
Fatty liver
Stroke
Peripheral vascular disease (narrowing of the arteries in the legs)
Polycystic ovaries (which can cause period problems and infertility)
Prostate cancer
Memory loss

What can be done?

We are not sure, but we think the risk can be reduced by losing weight, eating less refined carbohydrate and saturated fat, and by becoming more physically active. All good advice anyway and I’ll cover it in more detail later in the book.

Diabetes

What is it?

Diabetes is a condition where there is too much sugar (glucose) in the blood. Its full name is diabetes mellitus. It is very common in South Asians, particularly those who have moved to the cities and towns or to the West. One study found diabetes in:

2.5% of rural Indians
5 – 12% of urban Indians
20% of South Asians living in the UK
4% of White European men

Not only is diabetes more common in South Asians, it starts on average 10 years earlier than in White people.

What are the symptoms?

Often there are no symptoms, at least early on. Sometimes there are symptoms such as weight loss, tiredness, being very thirsty or passing a lot of water (urine).

What are the problems with diabetes?

Even though diabetes may not have any symptoms, it can damage blood vessels and tissues in many parts of the body. It can cause:

Heart disease (with greater risk for South Asians)
Foot ulcers
Painful nerve damage
Kidney failure
Problems with eyesight (cataracts, bleeding in the eye, blindness)
Problems with erections

Once you develop diabetes, it can reduce your life expectancy by as much as 5 – 10 years, particularly if it is not looked after properly.

What are the two types of diabetes?

Type 1
Also called:

Insulin Dependant Diabetes Mellitus (IDDM)
Juvenile onset diabetes

The pancreas stops releasing insulin, usually pretty rapidly. The patient often feels and looks unwell. Symptoms include weight loss, thirst and passing more water. It usually comes on in children or young adults. Treatment with insulin injections is almost always needed

Type 2
Also called:

Non-insulin dependant diabetes mellitus (NIDDM)
Late onset diabetes or maturity onset diabetes

Although the pancreas still makes insulin, the insulin does not work as well because of Insulin Resistance, which I explained above. The patient is less likely to have any symptoms, and so it is usually diagnosed at a check-up or when a doctor does a blood or urine test.

Type 2 is more common than type 1, especially in South Asians. Changing the diet and increasing activity or exercise can sometimes treat it. Later on, tablets might be needed. If it becomes more difficult to treat, then insulin injections might be required. Even though the patient often feels fine diabetes is harmful, so it is really important to follow the advice of the doctor or the nurse.

How is it diagnosed?

It is diagnosed by a blood test measuring glucose. If the glucose is above a certain level, you have diabetes. The level depends on whether the test was taken before breakfast (fasting) or at any other time in the day (random).

In most of the world, glucose is measured in units called mmol/l. In other countries including America and in the Indian Sub-continent, it is measured in mg/dl. It is also important to remember that glucose can be measured by taking blood from a finger prick or from the vein in the arm. The results are slightly different.

I am giving you the levels in a very simple way in the tables below. However, please talk to your doctor if you think you have diabetes.

Blood glucose levels (in mmol/l):

	Fasting	Random
Normal	Less than 5.1	Less than 7.1
Diabetes	More than 7.0	More than 11.0

Blood glucose levels (in mg/dl):

	Fasting	Random
Normal	Less than 92	Less than 126
Diabetes	More than 125	More than 200

Possible causes and triggers of type 2 diabetes are:

Your genes (the way you are made up)
Being overweight, especially around the middle
Not enough activity or exercise
A diet high in quickly digested starches and sugars (refined carbohydrates). But not all carbohydrates are bad. The more slowly digested starches in foods like oats are healthier. See the section on carbohydrates below for more information.
A diet high in saturated fats and trans fats
Inflammation and damage to the pancreas

Raised cholesterol

What is cholesterol?

Cholesterol is a waxy substance occurring naturally in the body. It is one of the fats - or lipids - circulating in the blood. A small amount is actually needed by the body to make cells and hormones. However, a high cholesterol increases the risk of heart disease.

Where does it come from?

Although cholesterol is naturally found in certain foods such as egg, most of the cholesterol in the body is made by the liver. Which, incidentally, is why eating the occasional egg is not as harmful as you may have been told (unless, of course, you have an egg-allergy or don't eat them on religious grounds).

What causes high cholesterol?

Eating too much saturated fat (e.g. butter, cream, whole milk, red meat)
Being overweight
Not enough exercise or activity
Your genes

What lowers cholesterol?

Eating less saturated fat
Losing weight
Exercise
Some medicines (for example, statins)

Different types of cholesterol - good and bad

Cholesterol moves around the body within particles called lipoproteins. There are a number of different types of lipoproteins, ranging in size.

The total cholesterol is made up of

Low-density lipoprotein (LDL) ("bad cholesterol")
High-density lipoprotein (HDL) ("good cholesterol")
Non LDL, Non HDL cholesterol

LDL is harmful because it increases the risk of heart disease. However, HDL probably reduces the risk by protecting the arteries from the effects of bad LDL. The remaining non-LDL, non HDL is mixture of lipoproteins, most of which are thought to increase risk.

Although South Asians tend not to have a very high total cholesterol, they have less of the good HDL compared to white people - one of the reasons they have more heart disease.

What increases the healthy HDL cholesterol?

Exercise
Monosaturates in the diet
Alcohol (in moderation)
Some medication (for example, statins)

What is a healthy cholesterol level?

Because of the different types of cholesterol - good and bad - it is not possible to answer this question simply. Looking at total cholesterol and HDL is more helpful than going by a total cholesterol result alone. A healthy cholesterol level or target will vary from one person to the next, depending on other factors such age, sex, blood pressure, diabetes, and smoking. There are graphs and computer programs available which will calculate risk based on all these factors. Your doctor will have one, or you could use one on the internet:

Framingham - based on a large study of the mainly white population of a town in Massachusetts, USA.
QRISK qrisk.org - more useful because it takes into account differences in South Asian populations in the UK

If you can't access a graph or computer program, and you have never had previously had heart disease or another high risk condition such as diabetes, then you should certainly consider talking to your doctor if your:

Total cholesterol is more than 5.0mmol/l or your
LDL cholesterol is more than 3.0mmol/l

However, the National Institute of Clinical Experts (NICE) (a group of UK experts) advise different cholesterol limits for people who have, or are at high risk of, coronary heart disease:

Total cholesterol - less than 4.0mmol/l (160 mg/dl)
LDL cholesterol - less than 2.0mmol/l (80 mg/dl)

These last, stricter, levels probably also apply to diabetics. Although some doctors believe that almost all diabetics should have treatment for cholesterol.

South Asians in particular must also take into account HDL. Advised levels of HDL are:

For women, HDL above 1.2 mmol/l (50 mg/dl)
For men, HDL above 1.0 mmol/l (40 mg/dl)

As you can see, giving cholesterol limits really isn't easy, and it is probably simpler to consult your doctor.

What should I do about my cholesterol?

The first step is to to measure it with a blood test. It is better to have the test before breakfast (fasting) and to ask for a 'lipid profile' or simply 'lipids', which includes total cholesterol, LDL, HDL and triglycerides. Your doctor, lab or pharmacist could do this.

The second step is to decide whether your lipid profile is healthy or unhealthy. It is simpler to ask your doctor, but you could talk to your pharmacist or use one of the on line calculators we mentioned above.

Everybody should try to keep slim, take exercise and eat a healthy diet low in saturated fat. If your lipid profile is unhealthy, then you should take extra care. If your profile does not improve with these 'lifestyle' measures, then your doctor might advise medicines such as statins.

Inactivity

Being physically inactive (or not taking enough exercise) can increase the risk of a number of conditions:

Coronary heart disease
Diabetes
Stroke
Hypertension (high blood pressure)
Osteoporosis

Traditionally in South Asian countries, the climate and low car-ownership encouraged walking and cycling. However, moving the cities or to the West has resulted in a reduction in activity. People are working long hours in desk-based jobs. More of our leisure time is spent in front of a TV or computer screen. Surveys of South Asians living in the UK have found we do less exercise than the general population. Many reasons are given:

Lack of time and working long hours
Having young children
Fear of exercising out alone
Embarrassment wearing exercise clothing
Lack of single sex facilities

Benefits of activity

I prefer the word 'activity' to 'exercise'. 'Exercise' suggests something you have to make a special effort to do, whereas 'activity' can be incorporated into everyday life - walking or cycling to work or school, taking a lunchtime or early-morning stroll, or playing with your children in the park or the garden.

Activity helps improve health in many ways, but it does have to be regular otherwise these benefits wear off:

Weight loss
Sense of well-being - less stress
Distribute fat away from the belly
Lower insulin levels and reduced risk from insulin resistance and the metabolic syndrome
Lower blood pressure
Strengthen the heart
Increased muscle tone - improved posture and appearance
Lower cholesterol
Lower triglyceride levels

Action points on activity:

Be more active (any activity is better than none):

In my opinion, exercise is probably the single most important intervention we South Asians can make to lower our risk of heart disease. Although we should aim to do at least half an hour of exercise or activity on at least five days per week, even a small increase in activity levels have been shown to improve health. The benefits add up, so even if you don't have time for a long exercise session, 3 ten-minute bursts of activity are still worthwhile.

Incorporate exercise into everyday activities:

Consider walking or cycling some or all of the way to the shops, work, school or college.
Get off the bus a few stops early and walk the rest of the way.
A folding bicycle can be very useful as you can ride it one way, and then at the end of a tiring day put it in a car, bus, train or taxi.
Use the stairs rather than the lift.
Gardening, housework and vacuuming may not seem particularly strenuous but they help to contribute towards beneficial activity levels.

Make a habit of exercise:

Some people find it easier to exercise if they make it a regular habit. In hot countries it might be preferable to take a daily walk, run or cycle in the cool of the the early morning, before getting ready for the day.

Although you don't need to join a gym, it can be a useful alternative to outdoor exercise if your weather is too hot or cold, your working day too long, or your daylight hours too short. A private health club subscription can be expensive, but off-peak membership may be cheaper. Your local municipal authority or university may offer inexpensive exercise facilities. UK residents with health problems such as diabetes, obesity or hypertension can often obtain free access to a gym through their General Practitioner (GP).

Vary the type of exercise you get:

Your body quickly adapts to the same exercise (and it gets boring). It's worth varying the type of exercise you take.

Adding resistance training to aerobic exercise improves strength and muscle tone and helps to burn fat. You don't need to use expensive machines - try circuit-training (which uses your own body weight) or using cheap hand weights (or even bags of sugar). There are plenty of training videos on youtube.com - search on 'resistance training' or 'body weight exercises'

Alcohol

I want to make it clear that I would not suggest you take up drinking alcohol if you object on religious grounds. However, we do know that people who take a little alcohol have 30-40% less heart disease than people who don't drink at all (teetotalers). When I say a little, I mean a little - people who drink heavily suffer higher rates of heart disease and have many other health problems, such as liver disease, memory loss, depression, sexual difficulties and cancer.

We don't know for certain why a small amount of alcohol reduces the risk of heart disease. We think that it increases the healthier HDL cholesterol. It also thins the blood, making it less likely to clot and cause a heart attack.

How much alcohol is safe?

For men, no more than 2 - 3 small drinks (units) on one day and no more than 21 in a week.
For women, no more than 1 - 2 small drinks (units) on one day and no more than 14 in a week.
Pregnant women should not drink at all. Even small amounts of alcohol can harm the growing baby.
It is not good to drink every day. Having 2 or 3 alcohol-free days a week gives your liver, brain and body a chance to rest.

What is a unit of alcohol?

A unit is roughly the amount of alcohol in a small drink. Unfortunately, units in different countries vary from 8 - 12 grams of alcohol. The number of units in a drink depends on how strong it is and how much there is. People find it hard to judge a unit, particularly when pouring a drink at home. Home measures are often much larger than those served in hotels or bars. It is safer to assume that a standard drink is 2 units.

A unit is:

One small glass of wine (125 ml or 4 fluid oz). Most wine glasses these days are 175 - 250 ml. Wine has been getting stronger and is now usually 11-13% alcohol. A 175 ml glass of wine is 2 units and a 250 ml glass is 3 units.
One small glass of weak beer (half a pint or 250 ml or 8 fluid oz). Weak beer is 3% alcohol, but most lager beer these days is 5%, so a small glass is 2 units and a large glass is 4 units.
One small shot or peg of whisky or spirit (25 ml or 1 fluid oz). A pub double or a home peg will contain twice as much alcohol. If you drink spirits, it is worth buying a measure to help you control your intake.

Food and diet

Introduction

The traditional South Asian diets were probably healthy. Unfortunately, what we eat has changed greatly. Migration to the cities, increased wealth, and pressure on time have led to us adopting the worst of both worlds, Eastern and Western. Not only do we eat more of the traditional sweets and deep-fried savouries which were once reserved only for special occasions, but we also have more of the fattening Western fast foods and convenience meals these days.

Variation in South Asian diets

There are a wide range of South Asian diets, for example vegetarian, vegan, meat-eating and fish-eating.

There are also variations in the types of cereals and staples grown and consumed. Punjab is famous for its golden fields of wheat, and people from Pakistan and Northern India tend to eat more bread. Rice is the staple of Bangladesh, as it is the main crop in the Ganges delta.

Similarly, there are differences in the fats and oils used. In the South of India and in Sri Lanka, more coconut-based products are consumed. Traditionally, clarified butter (ghee) was used in Pakistan and Northern India, but for reasons of economy and health, vegetable oils and vegetable ghee (Vanaspathi) have taken over - which, as we shall see later, are not necessarily healthier.

What are the main food groups?

Carbohydrates

Carbohydrates are one of the body’s main sources of energy. All carbohydrates are made of sugars.

Sugars are small molecules and are known as simple carbohydrates. Starches, found in bread, rice and potato, are large molecules made from lots of sugar molecules joined together. So starches are sometimes called complex carbohydrates.

Starches are digested in the stomach and intestine (gut) and broken down into sugars, which are absorbed into the blood stream. The rate at which this happens is called the glycemic index (GI). Low GI foods such as oats are generally healthier because they release sugars into the blood more slowly than high GI foods such as potato.

Sugar in the blood stimulates the release of insulin. The higher the blood sugar, the greater the amount of insulin released. High insulin levels can lead to insulin resistance, heart disease and central obesity.

Fibre (or roughage)

Fibre is special kind of complex carbohydrate the body cannot digest or use. It is helpful because it prevents constipation and can reduce cholesterol. It also makes you feel fuller for longer, making you less likely to reach for snacks between meals.

There are two different types of fibre – soluble and insoluble. Soluble fibre is generally better in helping to reduce cholesterol and is found in oats, ispaghula husk, and fruits. Insoluble fibre can be useful to prevent constipation, but sometimes causes abdominal pain and wind. It is found in bran and some grains. It is important to drink plenty of water when taking fibre, to prevent rare problems such as intestinal obstruction.

Protein

Protein is needed for growth. Because we all lose and make body cells daily, we all need protein.

Sources of protein include:

Nuts
Seeds
Pulses
Soya products
Cereals
Eggs
Dairy products
Meat
Fish

Protein is digested more slowly than carbohydrate, so adding protein to carbohydrate lowers the GI by making the meal sit in the stomach for longer.

Fats

There are many different types of fats, some good, some bad:

Saturated fats

Saturated fats tend to be solid at room temperature. Examples are the fat in red meat, coconut and butter. They are thought to be bad because they increase unhealthy cholesterol (LDL) and increase the risk of heart disease.

Unsaturated fats

Unsaturated fats tend to be liquid at room temperature. They can be divided into mono-unsaturated fats and poly-unsaturated fats.

Mono-unsaturated fats are thought to be good and are found in olive oil, peanuts (ground nuts), and rapeseed (canola) oil.

Poly-unsaturated fats are found in vegetable oils, nuts, seeds, fish, grains and margarines. There are different types of poly-unsaturated fats, for -example Omega-3 and Omega-6.

Omega-3 oils are thought to be beneficial in reducing the risk of heart disease and possibly helpful in preventing depression. Good sources are oily fish (such as sardines, salmon and mackerel) and flaxseeds (linseeds).

Omega-6 oils are found in sunflower, corn and safflower oil, and small amounts are essential for health. Although in the 1970s people thought these oils reduced the risk of heart disease, we now think that large quantities may actually increase the risk. Omega-6 oils can block the beneficial actions of Omega-3s. Also, Omega-6s can easily be changed by heating or by the action of the air (oxidation). These altered Omega-6s can damage blood vessels and make unhealthy cholesterol (LDL) more dangerous.

It is better to use monosaturates like rapeseed (canola) or olive oil for cooking at low temperatures rather than sunflower, corn or safflower oil.

For deep-frying, it is important to use an oil that remains stable and does not burn (has a high smoke point) – groundnut oil is a suitable example. This is because heating oils to temperatures near their smoke point can change the oil, by making it more saturated and more likely to damage blood vessels.

Trans-unsaturated fats (also called trans fats)

Trans fats are chemically altered vegetable oils. They are produced in a process called hydrogenation, which turns liquid oil into solid fat. This is used to make margarine, vegetable ghee and shortening.

Trans fats are thought to be particularly bad for the heart, because they increase unhealthy cholesterol (LDL) and reduce healthy cholesterol (HDL). They have no nutritional value but are often used in processed foods because they are cheap and make the food last longer.

They should be avoided, but sometimes aren’t listed on food labels. You should therefore avoid products that contain hydrogenated or partially hydrogenated oils or fats, such as:

Margarines
Vegetable ghee
Vegetable shortening
Chocolate spread
Some peanut butters
Doughnuts
Pastries
Biscuits
Mass-produced soft white bread

Micronutrients

Micronutrients are important parts of the diet, found only in small quantities. They included vitamins, minerals, anti-oxidants and bioflavonoids. I won’t cover vitamins and minerals here, as I’m discussing a few in detail later in the book.

Anti-oxidants and bioflavonoids are found in fresh fruit and vegetables. They protect the body from some of the harmful effects of aging and oxidation. Cooking usually easily destroys them, so as a rule it is better to eat fruit and vegetables either raw or only lightly cooked. Of course, some vegetables such as potato can’t be eaten raw, and all fresh foods should be washed before preparation. Some anti-oxidants are also vitamins (such as vitamins A, C and E), but there are others that aren’t conventional vitamins (such as lycopene found in tomato).

Problems with South Asian diets

Vegetable ghee

Vegetable ghee and margarines are made from vegetable oils by a process called hydrogenation. This makes the liquid oil semi-solid. Hydrogenation results in the formation of saturated fats and trans fats, which can increase unhealthy cholesterol and cause heart disease.

Deep frying

Deep frying is common in South Asian food and is used to make savoury snacks such as chevdha ('Bombay mix'), samosas and pakoras, as well as items used as ingredients in other dishes, such as vadhas and koftas.

Apart from on special occasions, deep-fried food is best avoided. The food is not only high in fat, but the high cooking temperature can change the oil molecules and make them more likely to damage blood vessels. This is even more of a problem if the oil is reused. The high temperature also results in the starches breaking down into sugars, making the food tastier but more glycemic (higher GI).

High Glycemic Index Diet

The South Asian diet has traditionally been based around rice or bread, which are usually high GI. I’ve explained how a high GI diet can make insulin resistance worse, which can increase the risk of heart disease and central obesity.

It is possible to lower the risk by eating a low GI diet. You don’t have to radically change what you eat but can start by making small changes in the types of carbohydrates used. Basmati rice is lower in GI than other varieties, such as Patna. The way you cook the rice also makes a difference – longer boiling or frying makes the rice softer and higher GI – better to boil for a short time, leaving it with a slightly firm bite.

Wholegrain cereals are usually lower GI than refined cereals. So brown rice is better than white rice, partly because it is less refined and therefore lower GI, and partly because it contains more fibre and vitamins. Unfortunately brown or wholemeal breads are only marginally better than white breads, because both are digested fairly quickly.

The amount of carbohydrate you consume also makes a difference, particularly if it is higher GI. You may have heard of something called ‘glycemic load’ which gives an idea of how much sugar the body has to deal with after eating a particular food. It is calculated by multiplying the GI of the carbohydrate eaten by its weight.

For example, watermelons are high GI, but because they contain a lot of water, the actual carbohydrate content is low. White rice is also high GI, but as it is dense (heavy) and often forms the main part of the meal, the carbohydrate content per serving is high. The glycemic load for a serving of rice is much higher than for a serving of watermelon.

It is certainly worth keeping to small portions of rice, bread and potatoes. I suggest no more than one or two ice cream scoops worth of rice, or no more than one or two wholemeal chapattis at one sitting. Avoid having both rice and bread with a meal. High GI breads such as pooris, parathas and nans are best kept for special occasions.

Low vitamin B12

Vitamin B12 is needed by the body to make blood and for the health of the brain and nervous system. It is found in foods of animal origin such as meat, shellfish or milk products. It is also added to certain breakfast cereals such as ‘All Bran’. Vegans don’t eat eggs or dairy products and so are prone to vitamin B12 deficiency unless they take a B12 supplement. Vegetarians who eat milk products or eggs will usually get enough B12. There are a few people who become deficient in vitamin B12 because even though they get enough in the diet they are unable to absorb it properly.

What are the problems with Vitamin B12 deficiency?

A lack of vitamin B12 can cause anaemia, tiredness, problems with memory and concentration, and loss of feeling in the arms and legs. It can also increase the risk of heart disease by increasing the level of homocysteine (see this post).

How is vitamin B12 deficiency diagnosed?

In the early stages there are often no symptoms, so the best way of diagnosing vitamin B12 deficiency is with a blood test. It is a good idea to ask your doctor for this test if you are vegan or vegetarian.

NEW RISK FACTORS AND AREAS OF RESEARCH

2009-11-13T23:08:00.003Z

Introduction

Although the risk factors we have so far talked about are important and fairly well established, there are new areas of research into why South Asians are more prone to heart disease. I am discussing them mainly for interest. Much of this work is experimental and we still do not know what do about some of the findings. It's therefore better to concentrate on treating the standard modifiable risk factors we have discussed above - like weight, inactivity, smoking, cholesterol, blood pressure and diabetes.

Lipoprotein(a)

What is lipoprotein(a)?

Lipoproteins are particles made of protein and fat. They carry cholesterol through the blood. There are different types, of which lipoprotein(a) is one. It may be more common in South Asians and is thought to be more damaging to the blood vessels than some of the other lipoproteins.

Should I have my lipoprotein(a) measured?

Unfortunately it is not common or simple to measure lipoprotein(a) directly. Doctors can get an idea from your lipid profile whether you might have a worrying level.

What can be done about lipoprotein(a)?

We don't really know. There isn't any specific medicine that will reduce lipoprotein(a). Statin medicines may help by increasing HDL and reducing total cholesterol. Some doctors suggest taking a high dose of a vitamin called Niacin (also called Nicotinic acid), however this can cause side effects so it's best taken under medical guidance.

Homocysteine

What is homocysteine?

Homocysteine occurs naturally in the body. It is a type of amino acid. We all have it, but some of us (particularly South Asians) have higher levels. People who have higher levels may suffer more damage to blood vessels, but we don't know if one causes the other or whether they are both linked by something else.

What can be done about a high homocysteine?

We think that homocysteine levels increase if the diet is short in certain B vitamins, such as B12, B6 and folic acid (or folate). You might think then that it is worth taking these vitamins to reduce the risk of heart disease. Unfortunately, we do not yet have the proof that this would work. One large study recently found out that taking B vitamins did not lower the risk.

The best advice for the moment is to make sure you eat a varied diet that contains all the necessary vitamins. Unless your diet is very bad, or you have some other reason such as pregnancy, taking vitamin tablets is not recommended.

Folic acid (also called folate) is found in green leafy vegetables and peas. It is added to breakfast cereals such as 'All Bran'.

Vitamin B12 is found in dairy foods, eggs, meat and fish. If you are vegan, it is possible to become short of vitamin B12, so it would be worth you talking to your doctor.

Vitamin B6 is found in beans, meat, poultry, fish, and some fruits and vegetables, particularly bananas and potatoes. It is also added to some ready-made breakfast cereals.

Should I have my homocysteine level measured?

It is possible to get homocysteine measured on a blood test, however it is not common and may be expensive.

As a rule in Medicine, it is only worth doing a test if the result would make you do or take something new. Because we are not sure yet whether it is possible or beneficial to treat a high homocysteine level, it is probably not worth having the test done.

Fibrinogen

What is fibrinogen?

Fibrinogen is a chemical which helps make the blood clot in injury. We all have it and need it. Because a high level of fibrinogen makes the blood thicker and more likely to clot, it is a risk factor for heart disease. South Asians have higher levels of fibrinogen than the white population.

What increases fibrinogen?

Inactivity
Smoking
Contraceptive pill
Alcohol
Genes

What can be done about a high fibrinogen?

Increase activity
Stop or reduce smoking
Keep alcohol to safe levels (see above)
If you are taking the contraceptive pill and are overweight, smoke, or have a strong family history of heart disease or blood clots, you should talk to your doctor. It might sound obvious, but don’t stop the pill without using another effective method of contraception (unless, of course, you want to get pregnant).

Should I have my fibrinogen measured?

It's not yet clear whether it is worth measuring fibrinogen routinely. However some doctors suggest it might be useful in someone with a strong family history of heart disease but no other obvious risk factors.

Smaller arteries

Cardiologists and heart surgeons have observed that South Asians tend to have smaller coronary arteries than white people, making them more likely to narrow or block early. Doctors also think that the plaques in South Asians might be more unstable, and therefore more likely to split open and cause a heart attack.

Inflammation

The coronary arteries have a delicate lining called the endothelium. Damage to this lining can lead to furring of the artery (called atherosclerosis). We now think that inflammatory chemicals can start the process off by attacking the endothelium. These chemicals are released by infections and are also released by abdominal fat.

Gum disease is an example of a long-term low-grade infection that could lead to heart disease. It now seems that flossing regularly may save lives as well as teeth!

In research, the level of inflammation is measured by a blood test called CRP (C reactive protein). It is a more sensitive version of the test usually carried out by your doctor, and we are not yet sure whether it is worth measuring in everyone.

Vitamin D

What is Vitamin D?

Vitamin D has many beneficial effects, but is mainly needed for the healthy development of our bones. We make most our vitamin D through the action of sunlight on the skin. A small part comes from the diet, mainly from oily fish, dairy food, margarine, eggs and meat.

We have known for many years that South Asians living in the cold, grey United Kingdom are prone to vitamin D deficiency. New research suggests that low vitamin D might also be a risk factor for heart disease.

Luckily, a deficiency is easily diagnosed and treated. It is worth talking to your doctor, particularly if you live in a cold climate.

Low Birth Weight

Some surprising new research suggests that underweight babies might be at greater risk of heart disease when they become adults. One explanation is that rapid catch-up feeding leads to central obesity and insulin resistance.

REFERENCES, FURTHER READING AND BROWSING

2009-11-13T22:34:00.004Z

Primary prevention of cardiovascular disease: a web-based risk score for seven British black and minority ethnic groups
Peter Brindle et al

Heart 2006;92:1595-1602
http://heart.bmj.com/cgi/content/short/92/11/1595

ETHRISK
A modified Framingham CHD and CVD risk calculator for British black and minority ethnic groups
Peter Brindle, Margaret May, Paramjit Gill, Francesco Cappuccio, Ralph D’Agostino Snr, Colin Fischbacher and Shah Ebrahim
www.epi.bris.ac.uk/CVDethrisk

Comparison of case fatality in south Asian and White patients after acute myocardial infarction: Observational study
Wilkinson P, Sayer J, Laji K, Grundy C, Marchant B, Kopelman P, Timmis A.
BMJ 1996;312:1330-1333

Coronary Artery Disease In Asian Indians: An Update And Review
Enas Enas & Annamalai Senthilkumar
The Internet Journal of Cardiology. 2001; Volume 1, Number 2
www.ispub.com/ostia/index.php?xmlFilePath=journals/ijc/vol1n2/cadi.xml#e15

The World Health Report 2002. Reducing risks, promoting healthy life
Geneva: World Health Organization, 2002
www.who.int/whr/2002/Overview_E.pdf

An Indo-Mediterranean diet was more effective than a control diet in primary and secondary coronary artery disease prevention
Jain, Meera, Rosenberg, Mark
Evid Based Med 2003 8: 76
http://ebm.bmj.com/cgi/reprint/8/3/76

The South Asian Health Foundation (SAHF)
26 Lightwoods Hill, Bearwood, West Midlands B67 5EA
Tel: 07802 288182
Website: www.sahf.org.uk
E-mail: info@sahf.org.uk

The Epidemic of Coronary Heart Disease in South Asian Populations: Causes and Consequences
First Edition
Editors:
Kiran C R Patel
Raj S Bhopal
South Asian Health Foundation 2004
http://www.sahf.org.uk/uploads/docs/files/21.pdf

British Heart Foundation
www.bhf.org.uk
Their website is a good source of information and leaflets on the prevention and treatment of heart disease.
Some of the material is available in South Asian languages.

PREVENTION, TREATMENT AND REHABILITATION OF CARDIOVASCULAR DISEASE IN SOUTH ASIANS
EDITORS:
Kiran C R Patel
Ajay M Shah
South Asian Health Foundation 2005
Published by TSO (The Stationery Office)
Also viewable online at http://www.sahf.org.uk/uploads/docs/files/11.pdf

Homocysteine Hypothesis for Atherothrombotic Cardiovascular Disease: Not Validated
Kaul, Sanjay, Zadeh, Andrew A., Shah, Prediman K.
J Am Coll Cardiol 2006 0: j.jacc.2006.04.086
http://content.onlinejacc.org/cgi/content/full/j.jacc.2006.04.086v1

Coronary Artery Disease in Young Indians –
The Missing Link
HS Rissam, S Kishore, N Trehan
Journal, Indian Academy of Clinical Medicine (2001) Vol. 2, No. 3: 128-132
http://medind.nic.in/jac/t01/i3/jact01i3p128.pdf

The Heart Outcomes Prevention Evaluation (HOPE) 2 Investigators,
Homocysteine Lowering with Folic Acid and B Vitamins in Vascular Disease
N Engl J Med 2006 354: 1567-1577
http://content.nejm.org/cgi/content/full/354/15/1567

Discover Magazine - Science and diet.

http://discovermagazine.com/2004/feb/science-diet

Willet's Healthy Eating Pyramid.

http://www.absoluteastronomy.com/topics/Healthy_eating_pyramid

Wikipedia, Healthy Eating Pyramid

http://en.wikipedia.org/wiki/Healthy_eating_pyramid (accessed 21 July 2009)

The Nutrition Source - Healthy Eating Pyramid

http://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/pyramid/

Alcohol intake and the risk of coronary heart disease in the Spanish EPIC cohort study.
Arriola et al.
Heart 2009;0:1–7. doi:10.1136/hrt.2009.173419
http://press.psprings.co.uk/heart/november/ht173419.pdf