Top 13 killer diseases: How COVID stacks up; heart disease doesn't grab headlines but kills 7 times more

[This article is not prescriptive, and is for informative purposes only. If you feel symptoms from any of the diseases mentioned, consult your physician.]

Food, a lack of exercise and pollution. Officially, they're today’s top killers. Bad lifestyle choices, especially eating the wrong foods, or just plain overeating, are the main culpits for nearly 18.6 million deaths from heart disease in 2019, a 17% jump from 2009, according to WHO data. It only gets worse from hereon: the annual death toll is projected to reach 30 million a year by 2030, warn experts.

Where does COVID stack up? For starters, the pandemic has killed 4.55 million in 19 months, an average of 239,473 per month or 7,982 per day. That's 332 per hour; about 5.5 per minute. Cardiovascular diseases (CVD), on the other hand, claimed 49,416 lives per day — 2,059 per hour, or 34 per minute. Cancers, the second-highest cause of disease, kills 3 times more than COVID.

A major risk factor for heart disease, "lifestyle change", is completely avoidable, say experts, but it’s also the hardest thing to do.

Still, infectious disease outbreaks grab headlines, while non-infectious diseases don't. But ignoring the risks for the latter won't make them go away.

Here are the top killer diseases, and where COVID-19 stacks up:

If you noticed the green (downward) arrows, they show where humans have improved on, in terms of reducing absolute numbers — especially on neonatal conditions and communicable diseases. That’s also thanks in huge part to inoculations. Yet, it’s the non-communicable diseases that account for the biggest disease burden.

Let's break it down:

What is it?

Ischaemic means an organ (e.g., the heart) is not getting enough blood and oxygen. Ischaemic heart disease (IHD), also called coronary heart disease (CHD) or coronary artery disease (CAD), is the term given to heart problems caused by narrowed heart (coronary) arteries that supply blood to the heart muscle.

It is caused by a decrease in blood flow through one or more of the blood vessels that carry oxygen to your heart (coronary arteries). When blood flow is reduced, the heart muscle does not receive the amount of oxygen it needs to function properly.

Atherosclerosis (thickening or hardening of the arteries) is the most common cause of myocardial ischaemia.

Impact

At 8.9 million deaths per year, CAD is the world’s top killer, accounting for 196.7 deaths per 100,000 people. The plaques that develop in thickened/hardened arteries can rupture, causing a blood clot. The clot might block an artery and lead to sudden, severe myocardial ischemia, resulting in a heart attack.

Symptoms

Treatment

Coronary heart disease cannot be cured. Treatment can help manage the symptoms and reduce the chances of problems such as heart attacks. It can include: lifestyle changes, such as regular exercise and stopping smoking, medicines such as:

What is it?

A stroke occurs when the blood supply to part of your brain is interrupted or reduced, preventing brain tissue from getting oxygen and nutrients.

Symptoms

Impact

Strokes killed 6.3 million people in 2019. When a person has a stroke, brain cells begin to die in minutes. A stroke is a medical emergency, and prompt treatment is crucial.

Treatment

Acting fast can help stroke patients. The stroke treatments that work best are available only if the stroke is recognised and diagnosed within 3 hours of the first symptoms. Stroke patients may not be eligible for these if they don’t arrive at the hospital in time.

If you think someone may be having a stroke, act F.A.S.T. and do the following simple test:

What is it?

It refers to a group of diseases that cause airflow blockage and breathing-related problems. It includes emphysema and chronic bronchitis.

Symptoms

Frequent coughing or wheezing.

Excess phlegm or sputum.

Shortness of breath.

Trouble taking a deep breath.

Impact

An estimated 65 million people suffer from chronic obstructive pulmonary disease (COPD) and 5.4 million died from it in 2020, making it the third leading cause of death globally.

Treatment

There's currently no cure for chronic obstructive pulmonary disease (COPD), but treatment can help slow the progression of the condition and control the severity.

Surgery is reserved for severe COPD or when other treatments have failed, which is more likely when a patient suffers from a form of severe emphysema.

What is it?

Coronavirus disease (COVID-19) is an highly infectious disease caused by the SARS-CoV-2 virus.

Symptoms

Most common symptoms are:

Less common symptoms:

Serious symptoms:

Impact

COVID -19 has infected nearly 220 million, and killed 4.55 million so far (over 19 months), and has disrupted life around the world due to lockdowns aimed to avoid the spread of infection.

Treatment

More than 20 vaccines approved to treat COVID-19, while antivirals, steriods, antibody therapies and a number of repurposed drugs are also approved either for emergency or full use to treat COVID-19.

What is it?

Symptoms

Less severe infections can have symptoms similar to the common cold, including:

In more severe infections, symptoms can include:

Impact

In 2019, 489 million incident cases and 11 million prevalent cases of lower respiratory infections (LRI) contributed to 2,49 million deaths and 97.2 million disability-adjusted life years (DALYs), according to tracking site healthdata.org

Treatment

Some lower respiratory tract infections go away without needing treatment. Less-severe viral infections can be treated at home with:

What is it?

Neonatal conditions are conditions occurring during the first month after birth (0- 28 days). The major contributors to the global burden of neonatal conditions include 1) premature birth, 2) neonatal infections, and 3) birth asphyxia.

Symptoms

Impact

Neonatal conditions lays a heavy burden on families, society, and the health system. Because they occur in the first few weeks of life, neonatal conditions are major contributors to the global toll of DALYs (disability-adjusted life years, having the most potential Years Lived with Disability (YLD) and Years of Life Lost (YLL).

There were 2.4 million neonatal deaths recorded worldwide in 2019.

Treatment

What is it?

Most lung cancers start in the lining of the bronchi, but they also can begin in other areas such as the trachea, bronchioles, or alveoli.

Symptoms

Impact:

This group of diseases accounted for 2.26 million deaths in 2019 worldwide. Exposure to air pollution is a major risk factor. Lung cancer has become more common before the twentieth century. It ranks the second and is the leading cause of cancer mortality.

In the case of the trachea, surgical removal of the tumour is the preferred treatment if the cancerous (malignant) or noncancerous (benign) tumour involves less than half of the trachea. Depending on the severity, bronchoscopic treatment, radiation/chemotherapy may be prescribed.

If the tumour is more extensive which precludes surgery, a patient may be given a number of palliative therapies to help restore breathing and slow tumour growth.

Treatment

It largely varies depending on the cancer may have spread to (a) the main bronchus; (b) lung lining, chest wall lining, or chest wall; (c) diaphragm; (d) heart or the membrane around it; (e) major blood vessels that lead to or from the heart; (f) trachea; (g) esophagus; (h) sternum; and/or (i) carina; and/or (j) there may be one or more separate tumours in the same lobe of the lung.

Dr Pranay Taori, an oncologist warned about the cross-morbidity between cardiovascular diseases and risk. He said "lifestyle” choices lead to diseases  like coronary artery disease (CAD), lower respiratory infections, respiratory cancers and diabetes.

What is it?

Dementia is the term applied to a group of symptoms that negatively impact memory, but Alzheimer's is a progressive disease of the brain that slowly causes impairment in memory and cognitive function. The exact cause is unknown and no cure is available. They can be caused by vascular cognitive impairment, traumatic brain injuries from vehicular accidents, falls, concussions, Parkinson's disease, Huntington's disease, HIV, as well as infections of the central nervous system.

Symptoms

Most common early symptoms include:

Impact

A major symptom of dementia is memory loss. If depression is also experienced, it makes it harder for a person with dementia to remember things and enjoy their life. Some people with dementia also experience hallucinations that can lead to paranoia, extreme anxiety and panic. 1.65 million people died of Alzheimer's disease and other dementias in 2019.

Treatment

Donepezil (also known as Aricept), rivastigmine (Exelon) and galantamine (Reminyl) are used to treat the symptoms of mild to moderate Alzheimer's disease. Donepezil is also used to treat more severe Alzheimer's disease, according to the UK’s National Health Service (NHS).

In June 2021, the Food and Drug Administration (FDA) approved aducanumab for the treatment of some cases of Alzheimer's disease. This is the first drug approved in the United States to treat the underlying cause of Alzheimer's by targeting and removing amyloid plaques in the brain.

What is it?

It is defined as the passage of three or more loose or liquid stools per day. Diarrhoeal diseases refer to a collection of diseases caused by multiple viral, bacterial, and parasitic organisms that share the common symptom of diarrhoea. Digestive tract problems may also be triggered by long-term use of some medicine, or with change in diet or medicines intake before or after surgery.

Symptoms

Impact

Diarrhoeal diseases are seen behind 1.4 million deaths globally. In general, they cause death by depleting body fluids resulting in dehydration. In children, diarrhoea can have a detrimental impact on childhood growth and cognitive development. About 88% of diarrhoea-associated deaths are attributable to unsafe water, inadequate sanitation, and insufficient hygiene.

Treatment

Other options: crackers, toast, eggs, rice or chicken.

What is it?

Diabetes mellitus (DM) refers to a group of diseases that affect how your body uses blood sugar (glucose). In general, it refers to uncontrolled high blood sugar over a prolonged period. This chronic (long-lasting) health condition affects how your body turns food into energy, CDC explains. Most of the food you eat is broken down into sugar (also called glucose) and released into your bloodstream. When your blood sugar goes up, it signals your pancreas to release insulin.

Insulin acts like a key to let the blood sugar into your body’s cells for use as energy. A diabetic person's body either doesn’t make enough insulin or can’t use the insulin it makes as well as it should. When there isn’t enough insulin or cells stop responding to insulin, high levels of blood sugar stays in your bloodstream. Over time, that can cause serious health problems, such as heart disease, vision loss, and kidney disease.

Symptoms

In general, symptoms of DM include:

Impact

Diabetes is responsible for 26.7 deaths per 100,000, according to the WHO. The impact of diabetes is felt long before a person’s death from complications. Possible long-term effects include damage to large (macrovascular) and small (microvascular) blood vessels, which can lead to heart attack, stroke, and problems with the kidneys, eyes, gums, feet and nerves.

Diabetic retinopathy, affects one-third diabetics, can cause blindness, if left untreated. “One of the major complications of diabetes is its effect on the eye, predominantly diabetic retinopathy,” said Dr. Soman Sukumaran Nair, an ophthalmologist at Zulekha Hospitals.

“This is a silent disease in the early stages but can cause blindness in the later stages. This imposes a severe economic and social impact as it predominantly affects people in their ages of peak productivity i.e. the fourth and fifth decades of their life,” Dr. Nair added. If diabetic retinopathy is diagnosed in a patient he/she needs to be examined by a retina specialist. The disease is subsequently staged after performing specialised tests. Based on the stage of the disease further treatment options such as lasers, eye injections and vitreous surgery may be considered.

Treatment

Adequate control of blood glucose and high blood pressure, correction of anaemia and elevated blood lipids can mitigate most of the morbidity associated with the disease.

Metformin is a tried and tested medicine that has been used for many decades to treat type 2 diabetes, and is recommended by most experts as first-line therapy. It is affordable, safe, effective, and well tolerated by most people. When metformin does not adequately control blood sugar, another medication must be added.

If diabetic retinopathy is diagnosed in a patient he/she needs to be examined by a retina specialist. The disease is subsequently staged after performing specialised tests. Based on the stage of the disease further treatment options such as lasers, eye injections and vitreous surgery may be considered.

In terms of foods, these are generally helpful in curbing the disease:

What is it?

Tuberculosis (TB) is an infectious disease that mainly affects the lungs. Mycobacterium tuberculosis, the bacteria that cause TB, spreads through tiny droplets released into the air through coughs and sneezes. Tuberculosis can also affect other parts of the body, including kidneys, spine or brain. Risk factors include weak immune systems, a medication that weakens the immune system, poverty, HIV infection, homelessness, being in jail, substance abuse, kidney disease and diabetes, organ transplants, healthcare workers, cancer and cancer therapy, smoking tobacco, among others.

Symptoms

Impact:

Tuberculosis can be found in all parts of the world. According to WHO, 44% of the cases in 2019 occurred in Southeast Asia, followed by Africa (25%) and Western Pacific (18). Significantly, 87% of the new cases were diagnosed in occurred in 30. Eight countries accounted for two-thirds of the new cases — India, Indonesia, China, Philippines, Pakistan, Nigeria, Bangladesh and South Africa.

Treatment

What is it?

Chronic kidney disease (CKD), also called chronic kidney failure, involves a gradual loss of kidney function. The most common causes of CKD are diabetes and hypertension, though the disease can be caused by many other conditions. Some examples of CKD are glomerulonephritis (kidney inflammation); polycystic kidney disease (inherited condition where growths called cysts to develop in the kidneys); blockages in the flow of urine – for example, from kidney stones that keep coming back, or an enlarged prostate.

Symptoms

According to the NHS, symptoms can include:

Impact

The major consequences of CKD include loss of kidney function leading to end-stage renal disease (ESRD), accelerated cardiovascular disease (CVD) and death. Other important complications include anaemia, bone disease, infections, reduced cognitive function and increased risk of acute kidney injury (AKI).

CKD killed 1.4 million in 2019.

Treatment

Later stages of CKD is known as kidney failure, end-stage renal disease or established renal failure. It may eventually require treatment with dialysis or a kidney transplant.

What is it?

Cirrhosis is a liver disease. It is one of the top causes of death globally, it’s also known as liver cirrhosis or hepatic cirrhosis. The liver damage done by cirrhosis generally can't be reversed. But if it is diagnosed early and cirrhosis can be treated, more damage can be prevented or limited.

Cirrhosis is a condition in which the liver is unable to function well due to long-term damage. When liver tissue is injured by disease (hepatitis B or C), excessive alcohol consumption or any other cause, it tries to repair itself. In the process, scar tissue replace live tissue resulting in fibrosis. The late-stage scarring is irreversible.

Symptoms

Cirrhosis normally don’t display signs or symptoms until the liver is damaged extensively. Some of signs and symptoms listed by the Mayo Clinic in the US include:

Impact

In 2017, 1.32 million died due to complications arising from cirrhosis. Cirrhosis deaths increased from around 676,000 in 1980 to over 1.55 million in 2010, a research paper published in BMC Medicine said.

Global cirrhosis deaths account for about 2% of the global total), a study published in The Lancet Gastroenterology & Hepatology states. The disease growing in both the West and the East. Egypt had the highest age-standardised mortality rate, while Mexican had the highest number of deaths in Latin America. In Asia, Thailand has the highest incidence of cirrhosis.

Risk factors for cirrhosis listed by Winchester Hospital in Maryland, US, include:

Treatment

Cirrhosis is normally first detected through a routine blood test. A combination of laboratory and imaging tests is carried out to confirm the diagnosis.

Cleveland Clinic recommends ways to prevent cirrhosis:

Most common reasons why people don't exercise: