Heart ailments are the leading cause of illness and death. Dr Ganeshakrishnan Iyer advises on how to keep your heart in a healthy condition
Cardiovascular diseases are the leading cause of illness and death in recent times. The main cause of cardiovascular disease is atherosclerosis, a condition in which cholesterol, fat, and fibrous tissue build up in the walls of large and medium-sized arteries.
In coronary artery disease (CAD), the arteries supplying the heart muscle (myocardium) are narrowed which results in reduced blood supply to the heart, causing chest pain (angina pectoris) or other symptoms, typically triggered by physical exertion. If a narrowed blood vessel is completely blocked by a blood clot, the area of the heart just beyond the blockage is denied oxygen and nourishment, resulting in a heart attack (myocardial infarction).
Like other degenerative disease processes, atherosclerosis can take years to develop. Diet is implicated because the deposits on arterial walls contain high levels of fat and cholesterol. Studies have shown links between dietary habits and atherosclerosis.
At least nine risk factors can help predict the likelihood of CHD: heredity, being male, advancing age, cigarette smoking, high blood pressure, diabetes, obesity (especially excess abdominal fat), lack of physical activity, and abnormal blood cholesterol levels. The more risk factors a person has, the greater the likelihood of developing heart disease. Risk factors are non-modifiable and modifiable. Non-modifiable risk factors imply risk factors that cannot be changed. However, people in these high-risk categories should receive regular check-ups.
Age: CVD becomes increasingly common with advancing age. As a person gets older, the heart undergoes subtle physiologic changes, even in the absence of disease. The heart muscle of the aged heart may relax less completely between beats, and as a result, the pumping chambers become stiffer and may work less efficiently. When a condition like cardiovascular disease affects the heart, these age-related changes may compound the problem or its treatment.
Gender: A man is at greater risk of heart disease than a pre-menopausal woman. Once past the menopause, a woman's risk is similar to a man's. Risk of stroke, however, is similar for men and women.
Family history/ heredity: A family's history of cardiovascular disease (CVD) indicates a person's risk. If a first-degree blood relative has had coronary heart disease or stroke before the age of 55 years (for a male relative) or 65 years (for a female relative), the risk increases.
Modifiable risk factors: The majority of cardiovascular disease (CVD) is caused by risk factors that can be controlled, treated or modified, such as hypertension (high blood pressure), high cholesterol, overweight/obesity, smoking/tobacco use, lack of physical activity and diabetes.
Hypertension
Blood pressure is measured as two numbers, written one over the other and recorded in millimetres of mercury - for example, 120/78 mm Hg. The top (higher) number is the systolic pressure - the pressure in the arteries as the heart is contracting - and the bottom (lower) number is the diastolic pressure - the pressure in the arteries when the heart is relaxed between beats. High blood pressure is defined as a repeatedly elevated systolic pressure of 140 or higher or a diastolic pressure of 90 or higher. Globally, nearly one billion people have high blood pressure (hypertension); of these, two-thirds are in developing countries.
Hypertension is one of the most important causes of premature death worldwide and the problem is growing; in 2025, an estimated 1.56 billion adults will be living with hypertension. It is the leading cause of CVD worldwide. People with hypertension are more likely to develop complications of diabetes. High blood pressure is called the "silent killer" because there are no warning signs or symptoms, and many people do not realize they have it; that is why it's important to get blood pressure checked regularly.
Diabetes
Diabetes is defined as having a fasting plasma glucose value of 7.0 mmol/l (126 mg/dl) or higher. The risk of cardiovascular events is from two to three times higher in people with type 1 or type 2 diabetes and the risk is disproportionately higher in women. In some age groups, people with diabetes have a two-fold increase in the risk of stroke. Patients with diabetes also have a poorer prognosis after cardiovascular events compared to people without diabetes.
Lack of early detection and care for diabetes results in severe complications, including heart attacks, strokes, renal failure, amputations and blindness. Insufficient physical activity can be defined as less than five times 30 minutes of moderate activity per week, or less than three times 20 minutes of vigorous activity per week, or equivalent.
Physical activity
Insufficient physical activity is the fourth leading risk factor for mortality. People who are insufficiently physically active have a 20 to 30 per cent increased risk of all-cause mortality compared to those who engage in at least 30 minutes of moderate intensity physical activity most days of the week.The prevalence of insufficient physical activity is higher in high-income countries compared to low-income countries due to increased automation of work and use of vehicles for transport in high-income countries.
Obesity
High dietary intakes of saturated fat, trans-fats and salt, and low intake of fruits, vegetables and fish are linked to cardiovascular risk. The amount of dietary salt consumed is an important determinant of blood pressure levels and overall cardiovascular risk and the WHO recommends a population salt intake of less than 5 grams/person/day to help the prevention of CVD.
Frequent consumption of high-energy foods, such as processed foods that are high in fats and sugars, promotes obesity compared to low-energy foods. High consumption of saturated fats and trans-fatty acids is linked to heart disease; elimination of trans-fat and replacement of saturated with polyunsaturated vegetable oils lowers coronary heart disease risk.
Adequate consumption of fruit and vegetables reduces the risk of CVD. A healthy diet can contribute to a healthy body weight, a desirable lipid profile and a desirable blood pressure. It is estimated that decreasing dietary salt intake from the current global levels of 9-12 grams/day to the recommended level of 5 grams/day would have a major impact on blood pressure and CVD.
High cholesterol
Raised blood cholesterol increases the risk of heart disease and stroke. Globally, one third of ischaemic heart disease is attributable to high cholesterol. Lowering raised blood cholesterol reduces the risk of heart disease. The prevalence of raised total cholesterol noticeably increases according to the income level of the country. In low-income countries, around 25 per cent of adults have raised total cholesterol, while in high-income countries, over 50 per cent of adults have raised total cholesterol.
Smoking, tobacco use
Risk of CVD higher among female smokers in comparison to males. he risk of CVD decreases substantially in 2 years after cessation of smoking and approaches risk for non smoking levels in about 15 years.
(The author is a senior consultant cardiovascular and thoracic surgeon at Vikram Hospital)