Smoking and high cholesterol are historically the two main causes of atherosclerosis, which causes cardiovascular disease. However, two nascent risk factors are causing more and more harm: stress and diabetes.
The effects of intense stress
Cardiologist and Director of Prevention at the Montreal Heart Institute Dr. Martin Juneau says that intense stress has a very significant effect on the autonomic sympathetic nervous system, which causes extensive direct stimulation of the heart, as do hormones such as adrenaline.
These changes, Juneau says, accelerate the heart rate and can induce severe heart arrhythmias or contraction of the coronary arteries. A striking example of the negative impact of stress is the sudden increase in mortality recorded in the weeks following the 9.1 magnitude earthquake followed by a devastating tsunami in Japan in 2011. The number of sudden deaths doubled compared with previous years, a trend that continued in the three weeks following the disaster.
People who do not have coronary artery disease but who are under intense emotional stress can suffer from syndromes known as "stress-induced cardiomyopathies,” Juneau continues. These problems mostly affect women (80% to 90% of patients), especially those who are postmenopausal. Described by Japanese cardiologists, tako-tsubo syndrome occurs when a person is exposed to severe stress or very bad news and suddenly develops severe chest pain similar to a myocardial infarction.
A vast number of studies have been published on the effect of chronic stress, negative emotions, anxiety, depression, anger and hostility on the long-term incidence of coronary heart disease, Juneau points out.
The effects of diabetes and junk food
People with diabetes are particularly prone to develop or die from coronary heart disease. The majority (65% to 80%) of people with diabetes will die from heart disease, the Canadian Journal of Diabetes reports. It is more likely to occur in general, and earlier in life, in people with diabetes, especially women. A high proportion of deaths occur in diabetic patients with no previous signs or symptoms of cardiovascular disease.
In addition, high rates of silent myocardial ischemia have been seen in people with diabetes, and almost one-third of myocardial infarction cases are observed in the absence of known or typical symptoms.
Junk food is also believed to play an important role in the development of heart problems. An Australian study published in August 2019 showed that more heart attacks occurred in neighbourhoods with the most fast-food restaurants: each additional fast-food restaurant caused four more heart attacks per 100,000 people.
The author pointed out that previous studies have associated the poor nutritional value and high fat and salt content of fast food with heart disease. In fact, junk food has spread throughout the world and is causing many public health problems, particularly in Asia.
Mortality risks and severity of heart failure
Studies have widely proven that heart conditions increase the chances of premature death. Compared with people who do not have coronary heart disease, a history of heart attack or heart failure, people living with heart disease are more likely to die from any cause in a given year, the Public Health Agency of Canada concludes.
All-cause age-standardized mortality rates were almost three times higher on average for Canadian adults living with diagnosed coronary heart disease compared with people without the disease in a given year.
If left untreated, coronary heart disease can lead to heart failure. This means the heart is unable to pump enough blood to meet the body's needs. The most common cause of heart failure is damage to the heart muscle as a result of heart disease. An estimated 50,000 Canadians are diagnosed with heart failure each year.
Symptoms of heart failure include shortness of breath, swelling in the legs and lack of energy. Treatment for this condition includes medication, limiting fluid intake and eating a low-sodium diet.