Erhabor: Obesity Is A Risk Factor for Asthma
Prof. Gregory Efosa Erhabor is a renowned Professor of Medicine and Consultant Chest Physician at the Obafemi Awolowo University and the Obafemi Awolowo University Teaching Hospital, Ile-Ife. He is also the President, Founder of Asthma and Chest Care Foundation. As the world marks World Asthma Day, he speaks on obesity as a leading cause of asthma while explaining effective management of the condition in this interview with Rebecca Ejifoma
Can we say Nigeria is doing well in terms of Asthma management?
We have come a long way from where we used to be. The World Asthma Day (WAD) is an annual international event with goals to improve asthma awareness and care around the world. Several chest physicians across the nation now celebrate WAD yearly to increase awareness in all the geopolitical zones by educating healthcare professionals, patients, caregivers and the public. This has improved public alertness; thereby, prompting quick response to patients with asthma when they need help.
Also, more resident doctors are showing interest in pulmonology and training to become chest physicians. This has resulted in more standardised ways of management in our various tertiary and secondary hospitals. Basic asthma medications, inhalational therapy and nebulisers are increasingly being used by a lot of hospitals and this shows some measure of progress. Although this still runs short of what is expected and there is still a big divide between what happens in tertiary hospitals and primary and secondary care services.
What are the statistics on asthma prevalence rate in Africa and Nigeria in particular?
Asthma prevalence ranges from high in countries like South Africa, which has a rate of 33.1 per cent to low in countries like Gambia with prevalence of 4.4 per cent. Nigeria’s prevalence falls in-between. Works that have been done in the ISAAC study and studies done by scholars in Nigeria show that the prevalence ranges from five per cent to 18.7 per cent depending on the cohort being studied. Most studies show that there is an urban-rural gradient with more asthma being diagnosed in urban than rural areas. Anecdotal evidence had shown that about 15 million Nigerians may have asthma. Works have been done in different regions of Nigeria with varying prevalence rates and meta-analysis is being conceived to see if we can correlate all the studies together to come up with something that will be more representative of the asthma picture in Nigeria.
Are there new risk factors associated with asthma management beyond smoking and other activities?
Basically, asthma results from interplay of genetic and environmental factors, a situation known as nature and nurture. Individuals with family history of asthma are prone to developing it. When individuals with genetic predisposition to asthma get exposed to certain triggers in the environment, they develop symptoms of asthma.
Triggers are extremely small and lightweight particles transported through the air and inhaled into the lungs. They precipitate asthma attacks and are usually found in the environment. Triggers include pollens, house dust mite, cockroach allergens, cold air, spores, fumes, smoke, sprays, perfumes; exercise, certain drugs like aspirin, tobacco smoke, prolonged exposure to air pollution, and agents found at work place like chemicals among others.
How does obesity cause asthma?
Within the last few years, there has been a growing number of literatures on the obese asthma syndrome. How obesity contributes to asthma in an individual may vary. However, these are a few ongoing factors that have come up as the relationship: Obese people are more susceptible to many strong risk factors of asthma like allergens, chemicals, cigarette smoking and air pollution.
There are many things that have been attributed to it but the common one is that the western diet, which promotes obesity, has high levels of saturated fatty acids, low fibers, low antioxidants and high in sugar. There is a growing literature that the harmful effects of these dietary components could lead to increased neutrophilic inflammation which predisposes to asthma and increased bronchodilator response.
In addition, there has been some studies showing that obesity can lead to low circulating Vitamin D and vitamin D deficiency has been implicated in the development of asthma and obesity.
Is Asthma prevalent in children?
Asthma is really not more prevalent in children as newer studies have shown. However, we need to do more multinational and intercontinental research to evaluate the prevalence because it appears asthma is still much underdiagnosed in both children and adults. Asthma runs a bimodal pattern – childhood asthma and adult asthma. Asthma tends to be more in number and in severity among boys than girls in childhood. This becomes balanced at puberty between ages 12 and 14. However, from age 15 to 50, females predominate.
Early childhood events may influence the development of asthma, the so-called hygiene hypothesis. What determines the progression is being debated. Some believe once you develop childhood asthma you continue to have symptoms. Others believe that there is a rule of third; that following development of asthma, a third goes into quiescence, some recover and others progress.
In 2016, the Nigerian Thoracic Society predicted that about 100 million Nigerians would suffer from asthma in 2025. What is your take on this?
I am not sure of that prediction of 100 million Nigerians having asthma. This is rather nebulous because the world prevalence of asthma is about 350 million. I think they may have been misquoted. I do not think Nigeria will have one-third of asthma sufferers in the world. Considering the current trend, that may not be possible but there could be increase in asthma prevalence as some of the factors responsible for asthma are still with us as industrialisation takes over the rural environment.
What are the newer therapies in the management of asthma?
Severe allergic asthma could sometimes be very difficult to treat, in other words they may not respond to the commonly used asthma medications. In recent times, several new medications, known collectively as ‘biologics,’ have been approved for the treatment of moderate-to-severe asthma. Biologics are unique in that they target a specific antibody, molecule, or cell involved in asthma. Because of this, they are known as ‘precision’ or ‘personalised’ therapy.
A biologic is a medication made from the cells of a living organism, such as bacteria or mice, that is then modified to target specific molecules in humans. For asthma, the targets are antibodies, inflammatory molecules, or cell receptors. By targeting these molecules, biologics work to disrupt the pathways that lead to inflammation that causes asthma symptoms.
Some examples of these drugs include: Omalizumab, which targets allergy antibodies known as IgE and Mepolizumab, reslizumab, and benralizumab which all target pathways that affect eosinophils-which are cells involved in the disease process of asthma. The commonest and most widely used is Omalizumab particularly in Europe, the United States and other regions. These drugs are used as add-on therapies for the treatment of inadequately- controlled severe persistent allergic asthma, despite the use of high dose inhaled steroid and long acting bronchodilators in patients aged 6 years or over.
Among those who used these drugs, severe exacerbations were noticed to decline significantly. Omalizumab is given by underneath the skin injection once every 2-4 weeks based on initial serum IgE level and body weight.
The major drawback of these agents is the prohibitive cost. For example, a vial of 150mg for Omalizumab, cost on the average $1,188. Aside this, these drugs are not readily available in most low and middle-income countries like Nigeria. Another disadvantage is that they are mostly injectable and so they have to be administered in the hospital setting under strict monitoring.
Adverse effects such as fever, increase susceptibility to upper respiratory infection, headache, fever, urticaria, injection site induration, injection site itching, pain, and bruising all contributed to making the use of these medications not very desirable.
Other forms of therapy include Bronchial Thermoplasty which is an innovative, non-drug procedure developed for the treatment of severe persistent asthma. It involves the use of thermal energy to reduce the increased airway muscle that is associated with airway constriction in asthma patients and also to prevent permanent airway damage, otherwise called airway remodelling.
In recent time, experts have also advocated the use of Tiotropium which is a long-acting antimuscarinic agent. This drug works by relaxing the airways smooth muscles and reducing the increase mucus secretion associated with difficult -to-treat asthma.
At what point exactly do you place an asthma patient on nebuliser?
Nebuliser is a drug delivery device used to administer medication in the form of a mist inhaled into the lungs. Nebulisers break up medical solutions and suspensions into small aerosol droplets that can be directly inhaled from the mouthpiece of the device. They can be oxygen driven, thereby giving a dual approach to effectively managing patients with asthma.
There are various forms of nebulisers. These include the ultrasonic, jet powered and mesh nebulisers. These devices are basically used in managing acute exacerbations of asthma, chronic obstructive pulmonary disease and in the delivery of certain medications in managing other diseases.
The aim of nebuliser therapy is to deliver a therapeutic dose of a desired drug as an aerosol in the form of respirable particles within a short period of time, usually five to 10 minutes.
The medications delivered via nebulisers can also be delivered using an inhaler with a spacer device and this may achieve the same result with a nebuliser.
However, nebulisers are useful in acute settings. It is useful when patients do not have spacer devices, if they are too young to cooperate or in the elderly who have poor co-ordination between device actuation and breath, or any condition that makes it difficult to use the inhaler therapy.
Research has shown that healthcare providers find it more convenient to administer nebulisers to patients in severe respiratory distress because less education or cooperation is required at such times, it can be oxygen driven, and it is less patient dependent.
How readily available are nebulisers and peak flow metres in our country?
Nebulisers and peak flow meters are now increasingly available in Nigeria compared to what used to happen in the past. OMRON has been actively involved in educating physicians, pharmacists and other healthcare practitioners globally on asthma and the use of peak flow meters, and other asthma devices like nebulisers. I am also aware that OMRON is collaborating with NEW HEIGHTS and they are involved in massive discounted sales of peak flow meters and nebulisers. Also, there are some pharmaceuticals who distribute peak flow metres free to patients. There have also been some charity organisations like Asthma and Chest Care Foundation and Breathe Easy Foundation, UK, who have been actively involved in distributing peak flow metres free of charge to patients. However, this is not enough. We look forward to more participation by philanthropists to make nebulisers, peak flow metres and asthma medications available to the masses.
One of my goals as a chest physician is to ensure that every asthmatic on the surface of the earth, especially in developing countries, have a peak flow metre available to him or her.
Amid the pandemic where getting medical attention is becoming difficult, what would you advise the average person living with asthma out there?
Management of asthma is usually a partnership between the physician and the patient with asthma. Asthmatics are encouraged to work with their physicians to develop a self-management plan which includes plan for acute exacerbation of asthma.
Central to this management is the following: It must be individualised and personalised. There is need to study their asthma and treatment must be personalised for each person.
Education is paramount. They need to be educated on asthma, the different components of asthma, how to recognise their triggers, inhaler techniques, self- management plan, amongst others.
The early use of anti-inflammatory drugs which include inhalational steroids is advocated; reserving rescue medications only for acute exacerbation. The lesser they are used shows a good management of their asthma.
The use of combination therapy using long acting beta 2 agonists and inhaled corticosteroids (such as Budesonide/Formoterol, Fluticasone propionate/ salmeterol, Fluticasone propionate/ Formoterol etc) for long term maintenance of asthma. These medications can also be used as rescue medications. There are other newer drugs used in advanced countries but these are not readily available and affordable. However, with concerted efforts by pharmaceutical industries and interest by philanthropic bodies, we may be able to bridge the gap between the developing nations and more industrialises countries.
As a principle, it is advised to take inhaled medications for asthma because it gets delivered to the site of action, and small doses give maximum effect. However, some inhaled medications can cause oral thrush and this can be prevented by using spacer devices or rinsing the mouth immediately after use; monitoring of their asthma using a peak flow meter which allows them to calibrate their asthma because the peak flow meter has a colour-coded portion red, yellow and green. The Green zone shows you have good control, no asthma symptoms and you can continue to take your medications as usual. Your peak flow reading at this time is between 80 and 100 per cent of your normal readings. The Yellow Zone is termed the zone of caution. The patient may have cough, wheeze, chest tightness or shortness of breath. He or she may be waking up at night due to asthma and can do some, but not all, usual activities.
Use your inhaled bronchodilator with your anti-inflammatory medications and you may think of either changing medications or increasing dose. The Red Zone is the medical alert. The patient is usually very short of breath and quick-relief medicines have not helped. That person needs urgent attention.
They should notice when their asthma is deteriorating for instance; when they have increasing symptoms of cough, wheeze, chest tightness and breathlessness, in spite of their usual medications; when they have to use increasing doses of their usual drugs; when they have to use additional drugs to be able to sustain a certain level of control; when they have to wake up at night because of asthma symptoms or have to wake up more nights in a week because of asthma; increasing environmental triggers or stressful events that may increase their asthma; when they find it increasingly difficult to do exercise or get breathless on mild to moderate exercise; a written self-management plan which will be personalised in case they have acute exacerbation of asthma.
Asthmatics should be managed as when there was no pandemic. When they notice deterioration in their health, they should contact the nearest health facility as soon as possible. The continual use of medications like aminophylline can be dangerous and should be discouraged. Early use of steroids is encouraged because of the anti-inflammatory properties.
With current pandemic, are more asthmatics presenting with COVID-19?
Current, observational research has shown that asthmatics do not come up with increased exacerbation during COVID-19. But this is still evolving because COVID-19 affects the parenchyma of the lungs rather than the lung airways.
Perhaps asthma protects against COVID-19 via a different immune response elicited by the disease. ACE 2 receptor expressed in respiratory epithelium have been documented as the route of entry of SARS-Cov2 in humans. However, asthma patients have a decreased expression of these ACE2 receptors.
Therapies used by patients with asthma can reduce the risk of infection or of developing symptoms leading to diagnosis. Suppression of viral replication was shown, as the inhaled corticosteroid, ciclesonide, blocks coronavirus RNA replication by targeting viral NSP15. There have also been reports of the inhibitory effects of glycopyrronium, formoterol and budesonide on coronavirus HCoV-229E replication and cytokine production by primary cultures of human nasal and tracheal epithelial cells.
How best can a severe allergic reaction like cough or wheezing be managed during the lockdown that would not be misconstrued for COVID-19?
As doctors, we usually say that all that wheezes is not asthma. However, wheezing is not one of the symptoms in COVID-19. Cough in COVID-19 is dry, continuous, associated with fever, sore throat, muscle aches, breathlessness and other constitutional symptoms. Cough in asthma is usually episodic, associated with wheeze, breathlessness, chest tightness, and triggered by exogenous factors. Having said this, the best way to have diagnosis for COVID-19 is to do the testing and tracking of symptomatic and exposed individuals. If you are having symptoms suggestive of COVID-19, report to centres responsible for testing, tracking and managing the disease. For asthma, diagnosis is from spirometry and demonstration of airway reversibility.
What are the correlations between a non-communicable disease like asthma and COVID-19?
A recent chat I had with colleagues from the American Thoracic Society revealed no increasing events of asthma episode in the COVID-19 pandemic. The use of ventilator in COVID-19 has a lot to do with increase in the lung fluids or what we call acute respiratory distress syndrome (ARDS).
The use of ventilator in asthma is reserved for patients who have life threatening asthma that has progressed from acute severe asthma, have low oxygen (hypoxemia), high level of carbon dioxide (hypercapnia), and has a silent chest, among others. These set of people must be managed in the intensive care unit. However, when they are on mechanical ventilator, they continue their medications such as bronchodilators, oxygen, anti-inflammatory medications and are also given additional medications like magnesium sulphate and heliox.
In carrying massive awareness campaigns on asthma management, what strategies would you suggest to reach those who need such education?
I met with a group of experts in Tromso, Norway about two years ago. We were thinking of the use of ‘M’Health as a means of education, and managing patients with disease like asthma and COPD. ‘M’ Health is a term used for practice of medicine and public health supported by mobile devices like phones, tablets, computers, PDAs, variable devices that are smart. This is a very easy way you can use your smart device to track the patients; it also contains applications that can allow the patients to make informed decision on what to do and also connect with their physicians in very severe condition. That is an innovative step.
Other things that can be done include increasing public awareness through television, newspapers, radio, social media networks and using various public fora. There is also need for mass education in schools, churches and mosques and massive distribution of asthma information booklets.
What is the role of government in the care for asthma patients?
The government plays a major role in making policies that favour healthcare and establishment of standard healthcare facilities nationwide. They can mitigate the burden of asthma on patients and caregivers by subsidising the cost of care for asthmatic patients.
Government should also partner non-governmental organisations like the Asthma and Chest Care Foundation in the provision of free or subsidised peak flow metres and nebulisers for asthma patients and in the production of ‘M’Health applications that can help patients in monitoring their asthma.
On a final note, we want to commend bodies like the Nigerian Thoracic Society headed by Prof. Prince Ele for the work done on asthma in Nigeria. The Asthma and Chest Care Foundation, my foundation, has also been in the forefront in the provision of education, patient care and counseling, training of health professionals; advocacy and conducting of research projects towards the enhancement of the lives of people with asthma and other lung diseases.
We look forward to philanthropists who will support these bodies so as to augment the efforts of the government in asthma management.
