Professional Journals
Is Cholesterol the Only Cause of Cardiovascular Disease?
Date: 11/11/2021
(Written by Dr. Jezamine Lim, Wellous Scientific & Research Advisor)

Cardiovascular diseases (CVDs) refer to a group of disorders related to the heart and blood vessels, including coronary heart disease, cerebrovascular disease, peripheral arterial disease, rheumatic arterial disease, congenital heart disease as well as deep vein thrombosis and pulmonary embolism. Some of the most common CVDs are heart attack and stroke. As of 26 November 2020, CVDs are the main causes of death in Malaysia, accounting for 23% of the 109,164 medically certified deaths in 2019. The prevalence of CVDs among Malaysian male and female populations in 2019 are 24.8% and 20.1% respectively.


Signs and Symptoms

During the onset of CVD, an individual may experience several symptoms like pain or discomfort in the centre of the chest (may last more than a few minutes), left shoulders, arms, elbows, jaw or back. Besides, one may also experience difficulty in breathing (shortness of breath), nausea/vomiting, light-headedness, cold sweat and face turning pale. Women may experience different symptoms from men. They are more likely to experience chest pain without pressure compared to men. In addition, they may experience certain symptoms such as shortness of breath, weakness, fatigue, nausea/vomiting, indigestion, palpitation as well as pain in the upper back, arm, neck and jaw, more often compared to men.


Major Causes of Cardiovascular Diseases

CVDs are caused by two major conditions, namely atherosclerosis and vascular calcification. Atherosclerosis, also known as arteriosclerosis, is a condition where plaque builds up in the arteries. The plaque is usually made up of excessive fats and cholesterol carried through the blood. This condition worsened over time when the plaque started to build up and narrow the arteries, which limits the flow of blood supply to various organs in the body, especially the heart in CVDs. Over time, the plaque builds up and totally blocks blood flow, leading to CVDs like heart attack. Atherosclerosis is usually associated with behavioural risk factor such as unhealthy consumption of food high in fats and cholesterol.

Unlike atherosclerosis, vascular calcification is a condition where minerals like calcium deposited in the blood vessels, leading to the hardening of blood vessels. There are two types of vascular calcification, namely intimal calcification and medial calcification. Intimal calcification is the deposition of calcium inside the blood vessels whereas medial calcification refers to calcium deposition around the blood vessels. Intimal calcification will cause obstruction in the arteries and limit blood flow to the heart like in atherosclerosis. While medial calcification decreases the flexibility and causes stiffness in the blood vessels. This results in a more fragile blood vessel that is prone to breakage as blood flows through them, leading to CVDs. Vascular calcification can also occur in heart valves, which changes the mechanical properties of the tissue and causes stenosis. This pathological condition is one of the consequences of aging.

 
Risk Factors of Cardiovascular Diseases

There are multiple risk factors associated with CVDs, including hypertension, unhealthy lifestyle, obesity, age, gender and psychology. Hypertension is one of the most important risk factors for CVD as high blood pressure often damages the blood vessels in the heart. In a study involving CVD risk factors among older populations in low and middle-income countries, hypertension was shown to be associated with angina in China, Russia and India while associated with stroke in China, India, South Africa, Ghana and Russia.

Besides, an unhealthy lifestyle also contributes to increased risk of CVDs. Unhealthy lifestyle includes consumption of an unbalanced diet with high cholesterol level and low fiber intake. High cholesterol level, especially low-density lipoprotein cholesterol, will lead to atherosclerosis and increase the risk of CVDs. Several studies have proven the association of CVDs with high intake of diet with high cholesterol level and insufficient intake of vegetables and fruits. Moreover, other unhealthy lifestyles like smoking and drinking also increase the risk of CVDs. Particularly, nicotine exposure was shown to increase atherosclerotic plaque in mice models when they were exposed to cigarette smoke. According to a study, the odds ratio of angina in India correlated with its high daily smoking rate of 46.9%. The same study also showed that frequent heavy drinking was one of the key risk factors for angina and stroke in China, which recorded a rate of 6.4%. Furthermore, physical inactivity may increase the risk of hypertension and even lead to obesity, which is another contributing factor of CVDs. It is reported that the total physical activity in 2009 had decreased by 29% among male community and by 38% in the female community following social, environmental and economic shifts in China. Due to the lack of physical activity, the population becomes more obese and eventually increasing the risk of CVDs. This is proven in a study where obese elder population with higher body mass index (BMI) was shown to be at a higher risk of getting heart attack and stroke compared to those with lower BMI.

In addition, other minor risks such as age, gender and psychological factors may also increase the risk of CVDs. For example, CVDs are more prevalent among older individuals compared to younger individuals. It is shown that the incidence rate of angina increased with age in numerous countries, including China, Ghana, India, Russia and South Africa. CVDs are shown to be more prevalent among male population compared to females as indicated in the data published by the Department of Statistics of Malaysia. The data showed 24.8% of males had CVDs whereas only 20.1% of females had the disease in 2009. In addition to the factors stated above, psychological factors like stress are also associated with CVDs. It is found out in an INTERHEART study that individuals who reported “permanent stress” at work or at home had more than 2.1 times the risk of developing heart attack compared to those who did not experience stress.


Impacts of Cardiovascular Diseases

The impacts of CVDs can be described in terms of the economic and social aspects. From an economic aspect, the impact of CVD is reflected through the costs involved in treating CVD patients, which are substantial. In Europe, the annual cost of treating CVDs is estimated to be around EUR 210 billion per year. Of this total amount, about EUR 111 billion (53%) is due to health care costs and EUR 54 billion (26%) is due to productivity loss. While the remaining EUR 45 billion (21%) is due to the costs spent on the time and effort given by informal caregivers such as CVD patients’ family members. The immense costs are attributed to the failure of recovering from CVD episodes, which leads to premature death and decreased productivity. The costs for productivity loss is usually high as the patients require time off to recover from CVD surgery and illness. This causes income loss for the patients and reduced productivity for employers, resulting in an overall economic loss.

From the social aspect, CVD affects the patients’ quality of life. This is because CVD patients may experience symptoms which prevent them from maintaining a good quality of life. It is reported that patients with chronic heart failure experienced various physical and emotional symptoms like chest pain, shortness of breath, light-headedness and depression, which limit their daily social and physical activities. This leads to poor quality of life. In a study assessing the quality of life of 205 patients with congestive heart failure and systolic dysfunction, it is shown that patients with lower cardiopulmonary function had significantly lower quality of life compared to those with healthy cardiopulmonary function.


Prevention of Cardiovascular Diseases

Due to the unfavourable impacts of CVD, it is important for individuals to prevent CVD before the disease starts to develop. Since individuals do not have control over their age and gender, CVD can be prevented by reducing the risk factors of the disease. One could start from reducing stress and improving their quality of life. For those who experience psychological stress, it is recommended for them to share their burden with their family and friends. They could also take up some hobbies to relieve stress.

Besides, one could also maintain a healthy lifestyle with regular physical exercise, avoid smoking, reduce drinking, maintain a balanced diet and ensure appropriate nutrient intake. Individuals are encouraged to exercise regularly to manage their body weight and maintain an optimum BMI (20 – 25). It is recommended for individuals to carry out 150 minutes of moderate intensity aerobic activity (e.g. walking and light gardening work) or 75 minutes of vigorous aerobic activity (e.g. jogging and swimming) per week. Individuals are also advised to stop smoking as it is the single most cost-effective intervention in CVD prevention and benefits could be observed within months of cessation. For drinking, the National Institute for Health and Care Excellence (NICE) advises a reduction of alcohol consumption to not more than four units per day for men and three for women.

To reduce the risk of CVD, it is necessary for individuals to maintain a balanced diet with low salt and saturated fats content, high in vegetables and fruits. This is stated in the Dietary Approaches to Stop Hypertension (DASH) diet recommended by the American Heart Association (AHA). The diet is shown to be an effective method to lower blood pressure and low-density lipoprotein cholesterol level, which are risk factors for CVDs. NICE, on the other hand, proposes reducing saturated fat intake while increasing the intake of monounsaturated fatty acids and five portions of fruit and vegetables every day. The institute also suggests a high fiber diet with two portions of fish every week. Moreover, AHA also recommends 1 gram of combined eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) daily for people with coronary heart disease.

Consuming heart healthy diets are important to prevent any heart related diseases. It's a preventable cause and don't forget to consume additional antioxidants to keep heart health at optimum level. Love yourself,love your heart ! 


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