The world's leading killer often announces itself first with a heart attack
Coronary artery disease caused 8.9 million deaths in 2015, about 15.6 percent of all deaths worldwide, more than any other condition. Fatty plaques slowly narrow the heart's own arteries, and for many people the first warning is not chest pain at all but a heart attack.
The underlying process is atherosclerosis, a chronic inflammation in which artery walls stiffen and collect cholesterol-laden plaques. When the vessels feeding the heart muscle narrow, oxygen supply falls short, most noticeably during exertion when the heart races and needs more. Some people then feel severe symptoms; others feel nothing. Roughly half of cases are linked to genetics, and the recognised risk factors include high blood pressure, smoking, diabetes, obesity, inactivity, high cholesterol, poor diet, depression and heavy drinking. Trans fats from partially hydrogenated oils and saturated fats from animal sources are singled out because their straight molecular shapes help them lodge along vessel linings.
Air matters too. Indoor and outdoor pollution is blamed for about 28 percent of coronary deaths, ranging from around 10 percent in highly developed regions to roughly 40 percent in parts of Africa and in South Asia, with fine particles from burning fossil fuels a key culprit. Job stress, by contrast, seems to account for only about 3 percent of cases.
The classic symptom, angina, is chest tightness or pressure that can spread to the arm, neck, jaw or back and sometimes mimics heartburn. Stable angina follows exertion or emotional strain and settles within minutes of rest; angina that shifts in intensity or frequency is called unstable and can precede a heart attack. Women often experience the disease differently, most commonly as breathlessness, along with fatigue, poor sleep and indigestion. Their symptoms generally begin about a decade later than men's, and they are less likely to recognise them.
There is encouraging news. For any given age, the risk of dying from the disease fell between 1980 and 2010, especially in wealthy countries, and new cases per age group also declined. In 2010 the condition affected about a fifth of Americans over 65 but only 1.3 percent of those aged 18 to 45.
Source: Coronary artery disease
