African Americans who smoke seem at higher risk of coronary heart disease

African Americans who smoke appear to have more than twice this risk of  developing coronary heart disease compared to those who do not smoke, a new study has found. The findings — the first up-close look at the relationship between smoking and coronary heart disease in this population—also examined the risk for plaque buildup in the arteries of African Americans who smoke. Excessive plaque in the arteries is a known predictor of heart attacks and heart failure.    

 The study, published today in the Journalof the American Heart Association, draws on data from nearly 4,500 participants in the Jackson Heart Study, the largest cohort study investigating cardiovascular disease exclusively in African Americans. That study, as well as the new research, is supported by the National Heart, Lung, and Blood Institute (NHLBI), and the National Institute of Minority Health and Health Disparities (NIMHD), both part of the National Institutes of Health.    

Coronary heart disease, the leading cause of death in the world, is the most common type of heart disease. In the United States, it affects more than 20 million adults(link is external) and causes one in seven deaths, according to the Centers for Disease Control and Prevention. It can develop when plaques build up in the blood vessels that supply the heart. These clogged, or calcified, arteries can limit or block blood flow and increase the risk for heart attack.    

Compared to whites, African Americans are more likely to die from coronary heart disease. Cigarette smoking causes inflammation and atherosclerosis, and coronary heart disease. Despite a marked decline in smoking among African American adults in recent years, almost 15% reported current cigarette smoking in 2019. Yet the link between cigarette smoking and coronary heart disease has been understudied in this population.    

African Americans have disproportionally higher rates of hypertension, diabetes, and obesity—known risk factors that partly explain the greater death toll from coronary heart disease in this community, according to the researchers.    

“But smoking is also a well-documented risk factor, which, combined with the others, suggest that African Americans smokers represent a particularly vulnerable population for this disease,” said lead study author Adebamike Oshunbade, M.D., M.P.H., a postdoctoral research fellow at the University of Mississippi Medical Center in Jackson. “However, our study is the first to focus on the relationship between cigarette smoking and coronary heart disease exclusively among a large cohort of African Americans.”      

Given the scant inclusion of African Americans in prior studies, researchers had limited ability to single out the specific effects of smoking, distinct from other risk factors, in this population. But with the Jackson Heart Study cohort of 5,306 participants, Oshunbade and colleagues were able to assess the relationship between smoking, coronary heart disease, and coronary artery calcification in African American adults.   

The investigators used coronary artery calcification (CAC) score measurements to assess the degree of calcified plaque buildup in participants’ coronary arteries. CAC score, which is measured by a CT scan, is a key predictor of an individual’s risk for cardiac events like heart attacks.      

For the study, 4,432 participants without a history of coronary heart disease at the time (2000-2004), were classified as current smokers, former smokers, or never smokers. After taking into account other risk factors — including smoking intensity, or the number of cigarettes each consumed daily — researchers followed the participants through 2016, tracking the development of coronary heart disease.     

The researchers found that, compared to those who never smoked, those who currently smoked had a more than two-fold higher risk of coronary heart disease. Similarly, those who smoke had an increased likelihood of having a higher CAC score.   

   “Smoking is a modifiable risk factor for cardiovascular disease and 73% of African American adults who smoke want to quit,” said David Goff, M.D., Ph.D., director of the NHLBI’s Division of Cardiovascular Sciences. “However, compared to whites, African American patients are less likely to receive information about smoking cessation treatments that we know can make a difference. Fully addressing tobacco-related disparities requires addressing conditions where people live, work, and play.” 

As the authors noted, the study was observational, and the findings do not establish casual links. Additionally, they should not be generalized to people of other races or regions.

Cardiovascular diseases (CVDs) number 1 cause of death globally

CVDs are the number 1 cause of death globally: more people die annually from CVDs than from any other cause, according to the World Health Organization.

An estimated 17.7 million people died from CVDs in 2015, representing 31% of all global deaths. Of these deaths, an estimated 7.4 million were due to coronary heart disease and 6.7 million were due to stroke .

Over three quarters of CVD deaths take place in low- and middle-income countries.

Out of the 17 million premature deaths (under the age of 70) due to noncommunicable diseases in 2015, 82% are in low- and middle-income countries, and 37% are caused by CVDs.

Most cardiovascular diseases can be prevented by addressing behavioural risk factors such as tobacco use, unhealthy diet and obesity, physical inactivity and harmful use of alcohol using population-wide strategies.

People with cardiovascular disease or who are at high cardiovascular risk (due to the presence of one or more risk factors such as hypertension, diabetes, hyperlipidaemia or already established disease) need early detection and management using counselling and medicines, as appropriate.

What are cardiovascular diseases?

Cardiovascular diseases (CVDs) are a group of disorders of the heart and blood vessels and they include:

• coronary heart disease – disease of the blood vessels supplying the heart muscle;
• cerebrovascular disease – disease of the blood vessels supplying the brain;
• peripheral arterial disease – disease of blood vessels supplying the arms and legs;
• rheumatic heart disease – damage to the heart muscle and heart valves from rheumatic fever, caused by streptococcal bacteria;
• congenital heart disease – malformations of heart structure existing at birth;
• deep vein thrombosis and pulmonary embolism – blood clots in the leg veins, which can dislodge and move to the heart and lungs.

Heart attacks and strokes are usually acute events and are mainly caused by a blockage that prevents blood from flowing to the heart or brain. The most common reason for this is a build-up of fatty deposits on the inner walls of the blood vessels that supply the heart or brain. Strokes can also be caused by bleeding from a blood vessel in the brain or from blood clots. The cause of heart attacks and strokes are usually the presence of a combination of risk factors, such as tobacco use, unhealthy diet and obesity, physical inactivity and harmful use of alcohol, hypertension, diabetes and hyperlipidaemia.

What are the risk factors for cardiovascular disease?

The most important behavioural risk factors of heart disease and stroke are unhealthy diet, physical inactivity, tobacco use and harmful use of alcohol. The effects of behavioural risk factors may show up in individuals as raised blood pressure, raised blood glucose, raised blood lipids, and overweight and obesity. These “intermediate risks factors” can be measured in primary care facilities and indicate an increased risk of developing a heart attack, stroke, heart failure and other complications.

Cessation of tobacco use, reduction of salt in the diet, consuming fruits and vegetables, regular physical activity and avoiding harmful use of alcohol have been shown to reduce the risk of cardiovascular disease. In addition, drug treatment of diabetes, hypertension and high blood lipids may be necessary to reduce cardiovascular risk and prevent heart attacks and strokes. Health policies that create conducive environments for making healthy choices affordable and available are essential for motivating people to adopt and sustain healthy behaviour.

There are also a number of underlying determinants of CVDs or “the causes of the causes”. These are a reflection of the major forces driving social, economic and cultural change – globalization, urbanization and population ageing. Other determinants of CVDs include poverty, stress and hereditary factors.

What are common symptoms of cardiovascular diseases?

Symptoms of heart attacks and strokes

Often, there are no symptoms of the underlying disease of the blood vessels. A heart attack or stroke may be the first warning of underlying disease. Symptoms of a heart attack include:

• pain or discomfort in the centre of the chest;
• pain or discomfort in the arms, the left shoulder, elbows, jaw, or back.

In addition the person may experience difficulty in breathing or shortness of breath; feeling sick or vomiting; feeling light-headed or faint; breaking into a cold sweat; and becoming pale. Women are more likely to have shortness of breath, nausea, vomiting, and back or jaw pain.

The most common symptom of a stroke is sudden weakness of the face, arm, or leg, most often on one side of the body. Other symptoms include sudden onset of:

• numbness of the face, arm, or leg, especially on one side of the body;
• confusion, difficulty speaking or understanding speech;
• difficulty seeing with one or both eyes;
• difficulty walking, dizziness, loss of balance or coordination;
• severe headache with no known cause; and
• fainting or unconsciousness.

People experiencing these symptoms should seek medical care immediately.

What is rheumatic heart disease?

Rheumatic heart disease is caused by damage to the heart valves and heart muscle from the inflammation and scarring caused by rheumatic fever. Rheumatic fever is caused by an abnormal response of the body to infection with streptococcal bacteria, which usually begins as a sore throat or tonsillitis in children.

Rheumatic fever mostly affects children in developing countries, especially where poverty is widespread. Globally, about 2% of deaths from cardiovascular diseases is related to rheumatic heart disease.

Symptoms of rheumatic heart disease

• Symptoms of rheumatic heart disease include: shortness of breath, fatigue, irregular heart beats, chest pain and fainting.
• Symptoms of rheumatic fever include: fever, pain and swelling of the joints, nausea, stomach cramps and vomiting.

Published courtesy of WHO