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Cardiovascular disease

life science Maturity 11-13 Vital Level 3 Next article →

Cardiovascular disease (CVD) refers to any medical condition that affects the heart or the blood vessels. This group of diseases is significant because it is the leading cause of death worldwide, except in Africa. In 2015, CVD caused 17.9 million deaths, which accounted for 32.1% of all deaths globally. This was a notable increase from 1990, when CVD caused 12.3 million deaths.

Deaths from cardiovascular disease ghe, World, 2021 (cropped)
Deaths from cardiovascular disease ghe, World, 2021 (cropped)

While death rates have declined in most developed nations since the 1970s, they are increasing in much of the developing world. Understanding how these diseases function is essential for prevention and treatment.

A major mechanism in many cardiovascular diseases is atherosclerosis. This process involves the buildup of substances within the walls of the arteries. This buildup can lead to coronary artery disease, stroke, and peripheral artery disease. Several factors contribute to this process, including high blood pressure, smoking, and diabetes mellitus. Obesity, a poor diet, and a lack of exercise also play roles. High blood cholesterol and excessive alcohol consumption are further contributing factors. When these processes occur, they can restrict the flow of blood through the body.

Cardiovascular calcification - Sergio Bertazzo
Cardiovascular calcification - Sergio Bertazzo

Cardiovascular diseases are categorized by which part of the system they affect. Vascular diseases involve the blood vessels. These include coronary artery disease, which affects the heart's vessels, and cerebrovascular disease, which affects the brain. Stroke is a type of cerebrovascular disease. Other vascular examples include peripheral arterial disease in the limbs and renal artery stenosis in the kidneys.

There are also many diseases that affect the heart itself. Cardiomyopathy involves the heart muscle, while arrhythmia refers to abnormalities in the heart rhythm. Valvular heart disease affects the heart's valves, and endocarditis is an inflammation of the heart's inner layer.

Certain diseases have specific causes or origins. For example, rheumatic heart disease can follow an untreated strep throat infection caused by Streptococcus pyogenes. This infection can damage the heart muscles and valves. Another type is congenital heart disease, which refers to malformations of the heart structure that exist at birth. Myocarditis is an inflammation of the heart muscle, often caused by viral infections. This condition is characterized by the infiltration of white blood cells, such as lymphocytes and monocytes, into the heart tissue.

Calcified Heart
Calcified Heart

Risk factors for CVD are divided into two main groups: modifiable and immutable. Immutable factors are those that cannot be changed, such as age, sex, and genetic predisposition. Age is the most significant risk factor, as the risk of developing CVD triples with each decade of life. Genetics also play a role; having a parent with CVD increases a person's risk by approximately three times. Most common cardiovascular diseases are non-Mendelian, meaning they are influenced by hundreds or thousands of small genetic variants. Modifiable factors are those that can be changed through lifestyle or medical treatment. These include tobacco use, physical inactivity, and diet.

Cardiovascular calcification - Sergio Bertazzo
Cardiovascular calcification - Sergio Bertazzo

Specific statistics highlight the impact of lifestyle and biological factors. Dietary risk factors are associated with 53% of CVD deaths. High blood pressure accounts for about 13% of deaths, while tobacco use accounts for 9%. Diabetes and a lack of exercise each account for 6% of deaths. Obesity is associated with 5% of deaths. Physical inactivity is a major concern, as it is the fourth leading risk factor for mortality worldwide. Conversely, participating in 150 minutes of moderate physical activity each week can reduce the risk of ischemic heart disease and diabetes by almost a third.

Biological differences between sexes also influence CVD risk. At the same age, men are about 50% more likely to develop CVD than women. Men are also typically diagnosed seven to ten years earlier. One proposed reason for this is the protective effect of estrogen in women. Estrogen may improve endothelial cell function and glucose metabolism. However, after menopause, estrogen levels decrease, which can change lipid metabolism. In women, high blood pressure combined with pregnancy complications can triple the risk of CVD.

Deaths from cardiovascular disease ghe, World, 2021 (cropped)
Deaths from cardiovascular disease ghe, World, 2021 (cropped)

Prevention remains a critical goal, as it is estimated that up to 90% of CVD may be preventable. Improving risk factors through healthy eating and regular exercise is highly effective. Avoiding tobacco smoke and limiting alcohol intake also reduces danger. Medical treatments for high blood pressure, diabetes, and high blood lipids are beneficial. For instance, treating strep throat with antibiotics can decrease the risk of rheumatic heart disease. While some treatments like aspirin are used, their benefit for otherwise healthy people remains unclear. By managing these factors, the global burden of cardiovascular disease can be reduced.

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