Cardiovascular disease (CVD) is any disease involving the heart or blood vessels. CVDs include coronary artery diseases (e.g. angina, heart attack), heart failure, hypertensive heart disease, valvular heart disease (e.g. rheumatic heart disease), cardiomyopathy, arrhythmia, congenital heart disease, carditis, aortic aneurysms, peripheral artery disease, thromboembolic disease, and venous thrombosis.
The underlying mechanisms vary depending on the disease. It is estimated that dietary risk factors are associated with 53% of CVD deaths. Coronary artery disease, stroke, and peripheral artery disease involve atherosclerosis. This may be caused by high blood pressure, smoking, obesity, high blood cholesterol, diabetes mellitus, poor diet, lack of exercise, excessive alcohol consumption, and poor sleep, among other things. High blood pressure is estimated to account for approximately 13% of CVD deaths, while tobacco accounts for 9%, diabetes 6%, lack of exercise 6%, and obesity 5%. Rheumatic heart disease may follow untreated strep throat.
It is estimated that up to 90% of CVD may be preventable. Prevention of CVD involves improving risk factors through: healthy eating, exercise, avoidance of tobacco smoke and limiting alcohol intake. Treating risk factors, such as high blood pressure, blood lipids and diabetes is also beneficial. Treating people who have strep throat with antibiotics can decrease the risk of rheumatic heart disease. The use of aspirin in people who are otherwise healthy is of unclear benefit.
Cardiovascular diseases are the leading cause of death worldwide except Africa. Together CVD resulted in 17.9 million deaths (32.1%) in 2015, up from 12.3 million (25.8%) in 1990. Deaths, at a given age, from CVD are more common and have been increasing in much of the developing world, while rates have declined in most of the developed world since the 1970s. Coronary artery disease and stroke account for 80% of CVD deaths in males and 75% of CVD deaths in females. Most cardiovascular disease affects older adults. In high income countries, the mean age at first cardiovascular disease diagnosis lies around 70 years (73 years in women, 68 years in men). The average age of death from coronary artery disease in the developed world is around 80, while it is around 68 in the developing world. At the same age, men are about 50% more likely to develop CVD and are typically diagnosed seven to ten years earlier than women.
Types There are many cardiovascular diseases involving the blood vessels. They are known as vascular diseases. Coronary artery disease (AKA coronary heart disease, ischemic heart disease) Peripheral arterial disease – a disease of blood vessels that supply blood to the arms and legs Cerebrovascular disease – a disease of blood vessels that supply blood to the brain (includes stroke) Renal artery stenosis Aortic aneurysm
There are also many cardiovascular diseases that involve the heart. Cardiomyopathy – diseases of cardiac muscle Hypertensive heart disease – diseases of the heart secondary to high blood pressure (hypertension) Heart failure – a clinical syndrome caused by the inability of the heart to supply sufficient blood to the tissues to meet their metabolic requirements Pulmonary heart disease – a failure at the right side of the heart with respiratory system involvement Cardiac dysrhythmias – abnormalities of heart rhythm Inflammatory heart diseases Endocarditis – inflammation of the inner layer of the heart, the endocardium. The structures most commonly involved are the heart valves. Inflammatory cardiomegaly Myocarditis – inflammation of the myocardium, the muscular part of the heart, caused most often by viral infection and less often by bacterial infections, certain medications, toxins, and autoimmune disorders. It is characterized in part by infiltration of the heart by lymphocyte and monocyte types of white blood cells. Eosinophilic myocarditis – inflammation of the myocardium caused by pathologically activated eosinophilic white blood cells. This disorder differs from myocarditis in its causes and treatments. Valvular heart disease Rheumatic heart disease – heart muscles and valves damage due to rheumatic fever caused by Streptococcus pyogenes, a group A streptococcal infection. Congenital heart disease – heart structure malformations existing at birth
Risk factors There are many risk factors for heart diseases: age, sex, tobacco use, physical inactivity, non-alcoholic fatty liver disease, excessive alcohol consumption, obesity, unhealthy diet, genetic predisposition and family history of cardiovascular disease, raised blood pressure (hypertension), raised blood sugar (diabetes mellitus), raised blood cholesterol (hyperlipidemia), undiagnosed celiac disease, psychosocial factors, poverty and low educational status, poor sleep, and air pollution. While the individual contribution of each risk factor varies between different communities or ethnic groups, the overall contribution of these risk factors is very consistent. Some of these risk factors, such as age, sex or family history/genetic predisposition, are immutable; however, many important cardiovascular risk factors are modifiable by lifestyle change, social change, drug treatment (for example prevention of hypertension, hyperlipidemia, and diabetes). People with obesity are at increased risk of atherosclerosis of the coronary arteries.
Genetics Cardiovascular disease in a person's parents increases their risk by ~3 fold, and genetics is an important risk factor for cardiovascular diseases. Genetic cardiovascular disease can occur either as a consequence of single variant (Mendelian) or polygenic influences. There are more than 40 inherited cardiovascular disease that can be traced to a single disease-causing DNA variant, although these conditions are rare. Most common cardiovascular diseases are non-Mendelian and are thought to be due to hundreds or thousands of genetic variants (known as single-nucleotide polymorphisms), each associated with a small effect.
Age
Age is the most important risk factor in developing cardiovascular or heart diseases, with approximately a tripling of risk with each decade of life. Coronary fatty streaks can begin to form in adolescence. It is estimated that 82 percent of people who die of coronary heart disease are 65 and older. Simultaneously, the risk of stroke doubles every decade after age 55.
Multiple explanations are proposed to explain why age increases the risk of cardiovascular/heart diseases. One of them relates to cholesterol level in serum. In most populations, the serum total cholesterol level increases as age increases. In men, this increase levels off around age 45 to 50 years. In women, the increase continues sharply until age 60 to 65 years.
Aging is also associated with changes in the mechanical and structural properties of the vascular wall, which leads to the loss of arterial elasticity and reduced arterial compliance and may subsequently lead to coronary artery disease.
Sex
At the same age, men are about 50% more likely to develop CVD and are typically diagnosed seven to ten years earlier than women. A notable exception are thromboembolic diseases which are similarly common in men and women. It has been argued that the excess risk of CVD observed in men compared to women only applied to the pre-menopausal period, but more recent data from the WHO and UN disputes this. If a female has diabetes, she is more likely to develop heart disease than a male with diabetes. Women who have high blood pressure and had complications in their pregnancy have three times the risk of developing cardiovascular disease compared to women with normal blood pressure who had no complications in pregnancy.
Coronary heart diseases are 2 to 5 times more common among middle-aged men than women. In a study done by the World Health Organization, sex contributes to approximately 40% of the variation in sex ratios of coronary heart disease mortality.Jackson R, Chambles L, Higgins M, Kuulasmaa K, Wijnberg L, Williams D (WHO MONICA Project, and ARIC Study.) Sex difference in ischaemic heart disease mortality and risk factors in 46 communities: an ecologic analysis. Cardiovasc Risk Factors. 1999; 7:43–54. Another study reports similar results finding that sex differences explains nearly half the risk associated with cardiovascular diseases One of the proposed explanations for sex differences in cardiovascular diseases is hormonal difference. Among women, estrogen is the predominant sex hormone. Estrogen may have protective effects on glucose metabolism and hemostatic system, and may have direct effect in improving endothelial cell function. The production of estrogen decreases after menopause, and this may change the female lipid metabolism toward a more atherogenic form by decreasing the HDL cholesterol level while increasing LDL and total cholesterol levels.
Among men and women, there are differences in body weight, height, body fat distribution, heart rate, stroke volume, and arterial compliance. In the very elderly, age-related large artery pulsatility and stiffness are more pronounced among women than men. This may be caused by the women's smaller body size and arterial dimensions which are independent of menopause.
Tobacco Cigarettes are the major form of smoked tobacco. Risks to health from tobacco use result not only from direct consumption of tobacco, but also from exposure to second-hand smoke. Approximately 10% of cardiovascular disease is attributed to smoking; however, people who quit smoking by age 30 have almost as low a risk of death as never smokers.
Physical inactivity
Insufficient physical activity (defined as less than 5 × 30 minutes of moderate activity per week, or less than 3 × 20 minutes of vigorous activity per week) is currently the fourth leading risk factor for mortality worldwide. In 2008, 31.3% of adults aged 15 or older (28.2% men and 34.4% women) were insufficiently physically active. The risk of ischemic heart disease and diabetes mellitus is reduced by almost a third in adults who participate in 150 minutes of moderate physical activity each week (or equivalent). In addition, physical activity assists weight loss and improves blood glucose control, blood pressure, lipid profile and insulin sensitivity. These effects may, at least in part, explain its cardiovascular benefits.
Diet
High dietary intakes of saturated fat, trans-fats and salt, and low intake of fruits, vegetables and fish are linked to cardiovascular risk, although whether all these associations indicate causes is disputed. The World Health Organization attributes approximately 1.7 million deaths worldwide to low fruit and vegetable consumption. Frequent consumption of high-energy foods, such as processed foods that are high in fats and sugars, promotes obesity and may increase cardiovascular risk. The amount of dietary salt consumed may also be an important determinant of blood pressure levels and overall cardiovascular risk. There is moderate quality evidence that reducing saturated fat intake for at least two years reduces the risk of cardiovascular disease. High trans fat intake has adverse effects on blood lipids and circulating inflammatory markers, and elimination of trans-fat from diets has been widely advocated. In 2018 the World Health Organization estimated that trans fats were the cause of more than half a million deaths per year. There is evidence that higher consumption of sugar is associated with higher blood pressure and unfavorable blood lipids, and sugar intake also increases the risk of diabetes mellitus. High consumption of processed meats is associated with an increased risk of cardiovascular disease, possibly in part due to increased dietary salt intake.
Alcohol