Cardiovascular disease (CVD) is an umbrella term for diseases of the heart and circulatory system, but what doctors don’t often have the time to explain is how any existing conditions, lifestyle and genetic profile interact with the disease. Ellie Broughton makes the links, and summarises the mortality statistics and risk factors for the key diseases that lead to or arise from CVD
Cardiovascular disease (CVD)
CVD covers all the diseases that affect the heart and circulation of blood around the body, namely coronary heart disease (CHD), which includes angina, heart attacks and strokes. Risk factors include smoking, high blood pressure or blood cholesterol, being inactive or overweight, having a history of CVD in your family or ethnic background. You’re also more likely to develop CVD if you’re older and men are more like to develop it younger than women. Stress, alcohol intake and deprivation all increase risk.
When one of the coronary arteries going in or out of the heart gets blocked and the heart stops getting the oxygen it needs from the blood, a heart attack occurs. Roughly the same number of men and women have heart attacks, but because they get more common with age, a woman is more likely to be admitted to hospital for a heart attack than a man because women live longer. Case fatality for heart attacks is measured for 30 days after the event; on that basis, around 85 per cent of women and 89 per cent of men survive.
When part of the brain has its blood supply cut off, either because a blood vessel has a clot or bursts, a stroke occurs. Risk factors include gender – men are more likely to have strokes than women – but age is the biggest risk factor, followed by ethnic group. Lifestyle factors, such as smoking and obesity, come in third. The World Health Report 2012 estimates that around 40 per cent of ischaemic strokes (the most common kind) are due to having a high blood cholesterol level. There is also a strong trend between stroke risk and deprivation.
Coronary heart disease (CHD), including angina, heart attack and stroke, may be caused by the same problem. When arteries get clogged with fatty atheroma they narrow. Less blood to the heart causes angina (heart pain) and a blockage in the arteries to the heart causes a heart attack. A blockage that stops the blood to the brain is a stroke. Atherosclerosis increases the risk of all three.
High blood pressure
A recent study estimated that 22 per cent of heart attacks in Western Europe were due to a history of high blood pressure. High blood pressure is also the leading cause of stroke.
More than a quarter of adults in England are obese. Obesity is probably the most important factor in the development of insulin resistance and therefore of diabetes. It is thought to be the primary cause of type 2 diabetes in people who are genetically predisposed to the disease, that is having a family history or being from an African-Caribbean or South Asian background. Risk factors include poor eating habits and a lack of exercise, but it has also been shown that for women, the lower your household income, the harder it is to keep off the weight.
Your body needs insulin to control the levels of glucose (sugar) in your blood. When it doesn’t produce enough, the walls of your arteries become more likely to develop fatty deposits (atheroma), which leads to atherosclerosis. Diabetes doesn’t kill like stroke or heart attack might, but it makes you more vulnerable to stroke, as well as blindness, chronic kidney disease, nerve damage and amputation if you don’t try to manage the condition. Risk factors for developing type 2 diabetes include being overweight or obese and inactive, having a family history of the disease, or coming from an African-Caribbean or South Asian background.
Diabetes damages small blood vessels in the body, generally those in the eye, kidneys and the casings around the nerves. If you have a lot of sugar (glucose) in your blood stream, the cells that line the blood vessels absorb much of it; then the walls of the blood vessels get thicker and weaken, which slows the flow of blood around the body. If your nerves or the cells in your eyes or kidneys don’t get enough blood flowing to them, they get damaged.
Chronic kidney disease (CKD)
Not so much as a disease as a poor level of function, CKD is a risk factor for CVD. The older you get, generally the worse your kidney function; women are more susceptible to CKD than men. Diabetes is a risk factor along with high blood pressure, but poorly functioning kidneys can also increase your blood pressure. Most people with CKD have high blood pressure and must try to keep it down to reduce the risk of also developing CVD.
Being physically active reduces your risk of developing CVD and diabetes. Eating well also protects you, even if you already have started to develop CVD. Cutting down on how much saturated fat you eat keeps cholesterol low. Reducing salt in your diet keeps your blood pressure low, and eating fibre, fruit and vegetables makes you less susceptible to CVD. Keeping your alcohol consumption low is also better for your CVD risk. If you have diabetes, you can reduce your risk of developing CVD by controlling your blood sugar, blood pressure and cholesterol levels. Statins keep your cholesterol levels low which reduces your risk of developing CVD or, if you have diabetes or CVD, the drug can treat the disease and prevent it from rapidly worsening.