Risk factors

Cardiovascular risk factors

There are many risk factors associated with coronary heart disease and stroke. Some risk factors, such as family history, cannot be modified, while other risk factors, like high blood pressure, can be modified with treatment.

You will not necessarily develop cardiovascular disease if you have a risk factor.  But the more risk factors you have the greater the likelihood that you will, unless you take action to modify your risk factors and work to prevent them compromising your heart health.

Modifiable risks factors

Physical inactivity and cardiovascular disease

The increasing urbanization and mechanization of the world has reduced our levels of physical activity. The World Health Organization believes that more than 60% of the global population is not sufficiently active.

If you are physically active you will increase your life span, regardless of any adverse inherited factors.  Physical activity, at any age, protects against a multitude of chronic health problems including many forms of cardiovascular disease.

Physical activity protects you by regulating your weight and improving your body’s use of insulin.  Being active is beneficial for your blood pressure, blood lipid levels, blood glucose levels, blood clotting factors, the health of your blood vessels and inflammation, which is powerful promoter of cardiovascular disease.

Studies show that doing more than 150 minutes (2 hours and 30 minutes) of moderate physical activity every week or an hour of vigorous physical activity every day will reduce your risk of coronary heart disease by about 30%.  
Even if you have existing risk factors for cardiovascular disease, if you keep active the evidence suggests that this may lower your risk of premature death compared to inactive people with no risk factors for cardiovascular disease. But if you do not keep active, the risk to your cardiovascular health is similar to that from hypertension, abnormal blood lipids and obesity. A middle-aged woman doing less than one hour of exercise per week doubles her risk of dying from a cardiovascular event compared to a physically active woman of the same age.

The good news is that even small increases in physical fitness are associated with a significant reduction in cardiovascular risk, even if you have existing disease.

Physical activity and stress
Stress has been shown to be a possible risk factor for cardiovascular disease. This is because living a stressful life can cause people to adopt poor habits like smoking and eating badly, which are risk factors for cardiovascular disease.
But being stressed itself can alter the way the body behaves and this can bring about changes to the blood and nervous system, which can have negative effects on your heart health.

One way to alleviate stress is through regular physical activities like running or riding a bike. This is yet another reason why it is important to maintain an active lifestyle

Physical activity and diabetes
If you develop diabetes you are at greater risk of developing cardiovascular disease.  Physical activity is known to reduce the risk of developing Type 2 diabetes. This is particularly true if you are at high risk of diabetes. If you do have diabetes, keeping physically active will better protect your heart.

One study showed that walking at least two hours a week reduced the incidence of premature death from cardiovascular disease by about 50%.  In people with diabetes exercise is thought to improve blood glucose control, which reduces the negative impact of diabetes on vascular health.

Tobacco and cardiovascular disease

The evidence that tobacco use will kill you is incontrovertible.
Since the 1940s it is known that smoking is linked to heart disease and cancer.  Since then, tobacco has appeared on an increasing roll call of risk factors for a host of diseases that cause death and illness.

And yet many people still do not link smoking to heart disease. For example, only 4% of Chinese know that smoking causes heart disease. In the USA, the majority of smokers do not believe they have a greater risk of heart disease than non smokers.

If you smoke and started smoking while still a child, your risk of cardiovascular disease is much higher than someone who started as an adult.

Being subjected to passive smoke will also increase your risk of cardiovascular disease. Chewing tobacco or using snuff is equally dangerous.

How tobacco causes damage
Smoking promotes cardiovascular disease through a number of mechanisms. It damages the endothelium (the lining of the blood vessels), increases fatty deposits in the arteries, increases clotting, raises low-density lipoprotein cholesterol, reduces high-density lipoprotein and promotes coronary artery spasm.

Nicotine, the addictive component of tobacco, accelerates the heart rate and raises blood pressure.

How genes compound your risk
Some smokers possess a gene that increases their risk of developing coronary heart disease by up to four times. About a quarter of us have this gene.

Gender
Women who smoke are at a higher risk of heart attack than men who smoke. If you are a woman and smoke three to five cigarettes a day, you double your risk of heart attack.  A man would have to smoke six to nine cigarettes a day to double his risk.

Reducing the risk
Although smoking causes a great deal of damage, quitting smoking effectively reduces cardiovascular risk to close to that of a person who has never smoked over a period of time.

Smoking is a major cause of heart disease. It is estimated that smoking increases the risk of stroke, coronary heart disease and impotence by 100%. Smoking increases the risk of death from undiagnosed coronary heart disease by 300%.

Diet and cardiovascular disease

The role of diet is crucial in the development and prevention of cardiovascular disease. Diet is one of the key things you can change that will impact all other cardiovascular risk factors. A diet high in saturated fat increases the risk of heart disease and stroke.  It is estimated to cause about 31% of coronary heart disease and 11% of stroke worldwide.

Comparisons between a diet low in saturated fats, with plenty of fresh fruit and vegetables, and the typical diet of someone living in the high-income countries show that in the former there is a 73% reduction in the risk of new major cardiac events.

Fat
Research makes it clear that abnormal blood lipid (fat) levels have a strong correlation with the risk of coronary artery disease, heart attack and coronary death. In turn, abnormal blood lipids are related to what you eat.  A diet high in saturated fats (e.g. cheese) and trans fats (often used in cakes, cookies and fast food) leads to high levels of cholesterol.

Saturated fats are found in animal products.  Trans fats are oils that have been hydrogenated to turn them into semi-hard fats.  Hydrogenated fat is found in processed food like shop-bought cakes, biscuits, stock cubes and a range of other products you buy every day. Saturated and trans fats raise cholesterol levels in the blood, which in turn can lead to atherosclerosis.

Unsaturated fats, polyunsaturated and monounsaturated are beneficial for heart health.  They are present in fish, nuts, seeds and vegetables.

The essential fatty acids omega-3 and omega-6 are found in oily fish and in nuts and seeds.  Our bodies cannot make these acids so we have to eat them to gain their benefits, which include improving good cholesterol levels in the body.

But it is important to note that if your total fat intake is greater than 37% of your total calories, then even if that fat is unsaturated you increase your risk of cardiovascular disease. Saturated fat intake should not exceed 10% of total energy and for high-risk groups, like people with diabetes, total fat intake should be 7% or less of total energy.

Learn more about which fats are bad and which fats are healthy.

Sodium
High blood pressure (hypertension) is a major risk factor for cardiovascular disease.  If you have a diet high in sodium you risk hypertension.

It has been estimated that a universal reduction in dietary intake of sodium by about 1g of sodium a day, about 3g of salt, would lead to a 50% reduction in the number of people needing treatment for hypertension.  The same decrease would lead to a 22% drop in the number of deaths resulting from strokes and a 16% fall in the number of deaths from coronary heart disease.

Fruits and vegetables
Eating a diet high in fresh fruits and vegetables protects your heart. Low fruit and vegetable intake accounts for about 20% of cardiovascular disease worldwide. Fruit and vegetables contain components that protect against heart disease and stroke.

Wholegrain cereals
Whole grains are unrefined and do not have the bran or germ removed. They contain folic acid, B vitamins and fiber, all of which are important protectors against heart disease.  Processed grains like that used to make white bread and pasta do not have the same benefits as wholegrain cereals.

Fish
In countries where fish consumption is high there is a reduced risk of death from all causes as well as cardiovascular mortality.

Alcohol

Harmful uses of alcohol has been shown to damage heart muscle and increase the risk of stroke and cardiac arrhythmia. Worldwide binge drinking (consuming large amounts of alcohol at one time) is responsible for about 2.5 million deaths and 4.5% of the global burden of disease. Consuming too much alcohol can also cause other problems such as increase blood pressure, acute myocardial infarction, cardiomyopathy, cirrhosis of the liver, violence, and suicide.

Some of our members have recommendations for how much alcohol is healthy for your heart. Learn more about their recommendations here:

British Heart Foundation
American Heart Association
Heart and Stroke Foundation of Canada
New Zealand Heart Foundation

Bad Fats

Much of the food we eat every day contains saturated and trans fats. They raise  the  blood cholesterol level, which may potentially clog up  the  arteries, putting one at greater risk of heart disease. Even everyday foods like meat and dairy products can have high levels of bad fats, so it’s often difficult to know what to put in the shopping basket.

Found out more about bad fats >

Blood lipids (fats) as a risk factor for cardiovascular disease

Abnormal levels of lipids (fats) in the blood are risk factors for cardiovascular disease.

Cholesterol is a soft, waxy substance found among the lipids in the bloodstream and in all the body’s cells. It is important to the healthy functioning of our bodies.  It is needed to form cell membranes and hormones.

The human body makes cholesterol and we also consume it when we eat animals and animal derived food like milk and cheese.  We can also make cholesterol from foods that do not contain cholesterol such as coconut fat, palm oil and trans fats, often used in foods such as french fries, cakes and cookies.

Cholesterol is carried through our blood by particles called lipoproteins: low-density lipoprotein (LDL) and high-density lipoprotein (HDL). High levels of LDL cholesterol lead to atherosclerosis increasing the risk of heart attack and ischemic stroke.  HDL cholesterol reduces the risk of cardiovascular disease as it carries cholesterol away from the blood stream.

Estrogen, a female hormone, raises HDL cholesterol levels, partially explaining the lower risk of cardiovascular disease seen in premenopausal women.

The other blood fat – triglyceride
Triglyceride is the most common type of fat in the body. Normal triglyceride levels vary by age and sex. But if you have heart disease or diabetes you are likely to have high levels.

High levels of triglyceride combined with high levels of LDL cholesterol speed up atherosclerosis increasing the risk for heart attack and stroke.

Normal blood lipid levels
Your lipid levels are dependent on your age, sex, genetic makeup, lifestyle choices, and will vary over time. Although a line between safe and dangerous levels is not easy to draw, there are recommendations that your physician will make.

European recommendations suggest the following targets:

Optimal total cholesterol: less than 5.0 mmol/l.
LDL cholesterol: 3.0 mmol/l or less.
HDL cholesterol: 1.2 mmol/l or more in women and 1.0 mmol/l in men.
Triglycerides: 1.7 mmol/l or less.

American recommendations suggest the following targets:

Optimal total cholesterol: 5.1 mmol/l.
LDL cholesterol: 2.6 mmol/l or less.
HDL cholesterol: more than 1.0 mmol/l.
Triglycerides: 1.7 mmol/l or less.

How hypertension impacts on your heart and blood vessels

Hypertension is the level of high or raised blood pressure for which investigation and treatment has been shown to do more good than harm. Generally hypertension is defined a systolic blood pressure level of 140 and above. This is a risk factor for coronary heart disease and the single most important risk factor for stroke. It causes about 50% of ischaemic strokes and increases the risk of hemorrhagic stroke.

Hypertension stresses your body’s blood vessels, causing them to clog or weaken.  Hypertension can lead to atherosclerosis and narrowing of the blood vessels making them more likely to block from blood clots or bits of fatty material breaking off from the lining of the blood vessel wall. Damage to the arteries can also create weak places that rupture easily or thin spots that balloon out the artery wall resulting in an aneuvrism.

Raised blood pressure in someone less than 50 years old is associated with an increased cardiovascular risk.  As you get older, your systolic blood pressure becomes a more important predictor of the risk of cardiovascular disease.

Dietary salt is a significant factor in raising blood pressure in people with hypertension and in some people with normal blood pressure.  If you are already overweight then a high intake of salt increases your risk of cardiovascular disease.

Types of high blood pressure
The amount of blood pumped by the heart and the size and condition of the arteries determines your blood pressure. However, many other factors can affect blood pressure including the condition of your kidneys and levels of various hormones in the body.

Some people experience essential hypertension, which has no identifiable cause. If you are diagnosed with this its origins may be genetic, or due to your lifestyle including diet, weight, and physical activity. Secondary hypertension is caused by another condition such as problems with your kidneys, certain medicines and some other medical problems.

Hypertension and cardiovascular disease
Hypertension is one of the leading risk factors for heart disease and stroke today. There are at least 970 million people worldwide who have hypertension.

In the higher income countries, about 330 million people have hypertension, as do around 640 million in the developing world.  The World Health Organization rates hypertension as one of the most important causes of premature death worldwide and the problem is growing. In 2025 it is estimated there will be 1.56 billion adults living with high blood pressure.

Obesity and cardiovascular disease

If you are overweight you may develop hypertension, diabetes and atherosclerosis.  These conditions will put you at high risk of cardiovascular disease.

You can tell if you are obese by the size of your waist, the ratio of your waist to your hips, and the relationship between your height and your weight.  This last measure is known as the Body Mass Index (BMI).  It is not a perfect way of checking your cardiovascular risk but as your BMI increases, so does your risk of heart disease and stroke.

Obesity across the world
Obesity is one of the many major risk factors for CVD and other NCDs like diabestes. The overall human population is getting heavier as shown by the increasing rates of obesity. Currently, there are 400 million adults worldwide who are obese and one billion who are overweight. There are also increasing rates of obesity in children. Worldwide, 17.6 million children under five are estimated to be overweight.

The latter half of the twentieth century saw major changes to all our diets and how we live.  We moved from plant-based diets to high-fat, energy-dense animal-based diets while at the same time becoming physically inactive. Many developing countries face the strange situation of having the problems of under nutrition and obesity, at the same time.

 BMI is calculated by dividing your weight in kilograms by the square of your height in meters (kg/m2).

If your BMI is greater than 25 you are considered overweight. If you are of south Asian origin you may be considered overweight if your BMI is greater than 22.  If you are a woman, a BMI greater than 21 may adversely affect your heart’s health.  If your BMI is more than 30, you are obese and at serious risk of cardiovascular disease. If your BMI is below 18.5 your are probably underweight.

Your waist measurement can also tell you if you are at risk of developing cardiovascular disease.

Increased risk High risk
Men – not Asian 94-101 cm >= 102 cm
Men – Asian >=  90 cm
Women – not Asian 80-87 cm >=  88 cm
Women – Asian >=  80 cm

How obesity causes cardiovascular disease
Previously, it was thought that fat was inert.  Now scientists understand that fat, especially intra-abdominal fat, has significant impact on our metabolism.

Intra-abdominal fat affects your blood pressure; your blood lipid levels and interferes with your ability to use insulin effectively.  You use insulin to process glucose derived from food, our body’s primary fuel. If you cannot use insulin properly you may develop diabetes, a risk factor of cardiovascular disease.

As you become overweight, your risk of developing Type 2 diabetes and hypertension rises steeply. Statistics show that 58% of diabetes and 21% of ischemic heart disease are attributable to a BMI above 21.

Non-modifiable risks factors

Family history and cardiovascular disease

If a first-degree male relative (e.g. father, brother) has suffered a heart attack before the age of 55, or if a first-degree female relative has suffered one before the age of 65, you are at greater risk of developing heart disease.

If both parents have suffered from heart disease before the age of 55, your risk of developing heart disease can rise to 50% compared to the general population.

Your chance of having a stroke is increased if first-degree relatives have had strokes. If they were young when they had their stroke, then the risk is slightly higher.  Studies have shown that the risk increases if you are a woman and your mother has suffered a stroke.

Studies have shown a genetic component for both hypertension and abnormal blood lipids, factors related to the development of cardiovascular disease.

One of the inherited factors is high cholesterol level, known as familial hypercholesterolemia.  If you have inherited this condition then you will experience a build up of low-density lipoprotein cholesterol in the blood. This can lead to coronary heart disease.

Type 2 diabetes also has a genetic component, so if one of your parents developed the condition you are at greater risk of developing it too.  Type 2 diabetes is another risk factor for the development of cardiovascular disease.

In the case of stroke, it is believed that inheriting hypertension is a key factor in the familial link of ischemic stroke.

However, you can protect yourself by taking care of your heart, as the development of cardiovascular disease involves many different factors, not just your family history.

Diabetes as a risk factor for cardiovascular disease

If you have diabetes you are two to four times more likely to develop cardiovascular disease than people without diabetes. Cardiovascular disease is the leading cause of mortality for people with diabetes.

If you have diabetes your risk of cardiovascular disease rises for a number of reasons. Hypertension, abnormal blood lipids and obesity, all risk factors in their own right for cardiovascular disease, occur more frequently in people with diabetes.

Diabetes and heart disease
Uncontrolled diabetes causes damage to your body’s blood vessels making them more prone to damage from atherosclerosis and hypertension. People with diabetes develop atherosclerosis at a younger age and more severely than people without diabetes.
Hypertension is more than twice as common in people with diabetes as in people with normal blood glucose levels.

People with diabetes are more likely to have a heart attack or stroke, than people who do not, and their prognosis is worse.
If you have diabetes you can have a heart attack without realizing it.  Diabetes can damage nerves as well as blood vessels so a heart attack can be ‘silent’, that is lacking the typical chest pain. If you have diabetes you have a two- to three-fold greater risk of heart failure compared to people without diabetes.

Premenopausal women who have diabetes have an increased risk of heart disease because diabetes cancels out the protective effects estrogen.

Diabetes and stroke
If you have diabetes and hypertension you are about twice as likely to have a stroke as somebody with hypertension alone. Your risk of transient ischemic attacks is between two and six times higher than somebody who does not have diabetes.

Diabetes and peripheral arterial disease
Diabetes can damage the blood vessels and over time this puts people with diabetes at far greater risk of intermittent claudication and lower-limb amputation compared to the general population. Intermittent claudication occurs three times more often in men with diabetes and almost nine times more often in women with diabetes than in their counterparts without diabetes.

Protecting yourself from cardiovascular disease if you have diabetes
If you control your blood glucose you can reduce your risk of a cardiovascular disease event by 42% and the risk of heart attack, stroke, or death from cardiovascular disease by 57%.

If you control your blood glucose levels you reduce your risk of cardiovascular disease by between 33% to 50%. If you control your blood lipids you can reduce cardiovascular disease complications by 20% to 50%.

Losing weight and maintaining a healthy diet will improve your diabetes status.
If you have impaired glucose tolerance and lose weight, you can prevent the onset of diabetes.
Stopping smoking will reduce your cardiovascular disease risk.

Risk factors for diabetes
The risk factors for Type 1 diabetes have not been proven yet.  It is thought that environmental triggers like viruses, toxins in the food chain and dietary components, may play a role.

The most significant modifiable risk factor for Type 2 diabetes is being overweight or obese. Smoking doubles the risk of cardiovascular disease if you have diabetes.

The most important non-modifiable risk factor is ethnicity, with Hispanics, Asians, Arabs, Africans, Pacific Islanders and indigenous (American, Canadian and Australian) populations at particular risk. Increasing age and a family history of diabetes also places you at greater risk.

Other common non-modifiable risk factors include

Age: Simply getting old is a risk factor for cardiovascular disease; risk of stroke doubles every decade after age 55.

Gender: Your gender is significant: as a man you are at greater risk of heart disease than a pre-menopausal woman.  But once past the menopause, a woman’s risk is similar to a man’s. Risk of stroke is similar for men and women.

Ethnicity: Your ethnic origin plays a role.  People with African or Asian ancestry are at higher risks of developing cardiovascular disease than other racial groups.

Socioeconomic status: Being poor, no matter where in the globe, increases your risk of heart disease and stroke. A chronically stressful life, social isolation, anxiety and depression also increase the risk.