Interview with Prof. Martyn Partridge.
"No government can ignore a disease that affects at least 3.5 per cent of its population. And asthma, which affects at least 3.5 per cent to over 20 per cent of population in any country, cannot be afforded to be ignored," says Dr. Martyn Partridge, Professor of Respiratory Medicine in Charing Cross Hospital, London, and Honorary Consultant Respiratory Physician to Hammersmith Hospitals National Health Service Trust, U.K.
Dr. Partridge was former Chairman of the British Thoracic Society Executive Committee. He now chairs the Respiratory Alliance, U.K. He is the Chief Medical Adviser to the U.K. National Asthma Campaign, the Chairman of Trustees of the U.K. National Respiratory Training Centre (NRTC), and the Vice-President of the NRTC, U.S.
Dr. Partridge is on the board of several prestigious international committees, including the Global Initiative for Asthma (1991-2003), the Medical Aerosol Sub-committee of the United Nations Environment Programme (which oversaw the phasing out of CFC inhalers (1992-2002)), and the Clinical Steering Committee of the London Ambulance Services. He was instrumental in setting up the National Asthma Foundation of India. Dr. Partridge, who was in Chennai recently to deliver a lecture on "Asthma: Challenges for the Present and Future", spoke to Asha Krishnakumar on the incidence of asthma, its treatment, management of asthma patients, and the current research in the area. Excerpts from the interview:What is asthma and what are its symptoms?
Basically, asthma means irritable airways, which, coming into contact with a variety of stimuli or triggers, lead to coughing, wheezing (a whistle-like sound heard from the chest while breathing), tightness in the chest and breathlessness. The key features are that the symptoms vary with time. It is often the worst in the morning, it may wake up the sufferer at night or it worsens after exercise.
What is the incidence of asthma? Does it vary across countries?
It is believed that there are about 300 million people suffering from asthma throughout the world. Asking the same question in different places or at different times, we begin to standardise the questions and we find variations in the prevalence among countries. For instance, Australia, New Zealand, northern Europe and the U.K., seem to have very high rates of incidence.
Studies done in India, however, show that the problem is not inconsequential. Studies among children put the incidence from 5 per cent to 12 per cent. In adults, between the ages of 20 and 44, studies suggest an incidence of 3.5 per cent. But considering India's population, that is a sizable number. And, it is almost certain that the figure is much higher because people with asthma are not diagnosed properly.
What are the reasons for such a large variation in the incidence of asthma across countries?
It seems to go with Westernisation, development, civilisation and so on. Studies in Zimbabwe showed that 6.8 per cent of the children who were made to exercise in the most prosperous areas of Harare had asthma. And when children in the poorer areas of Harare were made to exercise, the incidence was just about 3 per cent. And when they went out into the bush, they had to make hundreds and hundreds of children exercise to find one child with symptoms of asthma. So, we do not know if there is something that gives protection for those living in the rural areas where you are in close proximity to animals, and sanitation may not be very good. That may probably in some way be protecting you from asthma. But living in an urban area is probably bad for asthma.
How do you find out the prevalence of asthma in different population groups that show normal lung function and no symptom of the disease?
(Dr. Raj Singh, Respiratory Consultant, Apollo Hospitals, Chennai, who was present during the interview provided the answer.) When the lung function is normal and there are no symptoms of asthma, the incidence of the disease in the adult population is found out by a lung function test using spirometry. But that test is difficult to be done on children, so they are made to exercise and then their symptoms are studied.
What roles do genetic and environmental factors play in causing asthma?
We know that this is a disease that can run in families. Thus, it is almost certain that there is a genetic contribution. We cannot change our genetic contribution in 30 years. And it is not just a single gene that is contributing to asthma, as in the case of diseases such as muscular dystrophy. It is likely that you inherit different genetic linkages that may give rise to different predispositions and different patterns of disease.
But other things have made us more susceptible to asthma over the last 10-20 years. The rate of breast-feeding, for instance, has fallen. More mothers smoke. In several countries, there has been a significant change in diet - more processed and well-refined food - over the last few years. If, for instance, people consume a lot of magnesium, they have lower rate of asthma; that advantage is lost if fresh vegetables are over-cooked. Also, if people eat oily fish two or three days a week, they have lower rates of asthma. These individually may not have an impact on asthma rates. But they may all be responsible.
These variations in diet may make us more susceptible to asthma. This, along with other changes in lifestyle such as the use of soft furniture, less ventilated homes, and so on, and also pollution (which probably is not a major causative factor) may lead to an increase in asthma rates.
But, honestly, we do not know which of the many likely factors are responsible for an increase in asthma incidence. It is likely that more than one factor is switching on this disease in more people now than it did 10-20 years ago.
Does the incidence of asthma vary with sex, age and ethnic groups?
It varies with sex, depending on the age. Among children, more boys have asthma than girls. And among adults, it is found more in females than males. I am not convinced that there is any ethnic variation in the incidence of asthma. But if you are an African-American male living in the U.S., you are four times more likely to die of asthma than if you are a white American male. I am not sure if that variation is because of genetic disposition, or cultural, ethnic or socio-economic differences; probably the former group live in less optimal housing or they have less access to healthcare.
Why does the incidence of asthma vary so much between developed and developing countries?
It depends on which study you look at. In the case of the international study on Allergy and Asthma in Children, which standardised questions and did not depend on a doctor-diagnosed asthma and was done at one point in time, it is clear that there are big differences among countries. The range was from 4 per cent to 16 per cent among the children who were diagnosed by a doctor. If we looked at children who reported wheezing in the last year, the range was from 4 per cent to over 20 per cent. That sort of scatter was found. But it tended to be similar in the case of northern Europe, Australia and New Zealand, where the incidence of asthma has increased so dramatically over the last 10-20 years. This is almost a warning for the countries that have a lower prevalence to be prepared.
This is something the WHO (World Health Organisation) is aware of. After communicable diseases (the incidence of which will hopefully fall), a whole lot of non-communicable diseases such as depression, heart ailments, diabetes and respiratory diseases (asthma, chronic obstructive pulmonary disease, occupational lung diseases, lung cancer and the damage of lungs owing to tuberculosis) are rising rapidly. And we have to be prepared to manage them.
What are the diagnostic techniques available for asthma?
As in the case of many ailments, it is by studying a variety of symptoms and signs that asthma is detected. All the symptoms I mentioned earlier - wheezing noises in the chest, etc., and how fast an adult can blow out (peak flow reading) and so on - are used to diagnose asthma. It is very good to have access to investigations, but most important is clinical diagnosis.
What treatment options are available for asthma?
The lives of many of the 300 million people with asthma around the world have been transformed over the last 20-30 years by the introduction of tiny doses of steroids administered by inhalation directly into the airways where they need to act. Unfortunately, very often people seem to muddle up this concept of steroids with those that athletes abuse and tablets that are very, very large doses of steroids. Asthma patients need very small doses to reach the airways. Thus, the key thing is for people to understand the overwhelming evidence in favour of using low doses of inhaled steroids. All the guidelines around the world confirm that this is the optimal treatment.
But the sad thing is that people often rely on `relieving treatment' as against `preventing treatment' as the latter has to be taken regularly and over long periods. The `relievers', people should understand, are like putting a plaster on a boil, which does nothing except hide the boil from sight.
When you say people "muddle up" the concept of steroids, whom do you refer to - doctor, patient or pharmacologist?
There are general misconceptions. But as with any long-term medical condition, we need a totally different approach. It is not like going to your doctor for an upset stomach or an acute chest infection. People with asthma have to live with it, for it is a long-term condition. So, they have to be taught about the disease, have to be told about self-management skills, their compliance has to be enhanced by hearing out their fears and concerns about medication or what will happen to them over time, and they need to be given access to independent sources of information.
Treatment is a long-drawn process. So, how does one ensure compliance?
We are upfront about this. We do not have a cure for it as yet. Billions of pounds are being spent on research to find out why people get it and how it can be switched off when they get it. We cannot do that yet. But we can control it so that people can lead normal lives. But if they do not take the treatment, they run the risk of their lung function being seriously damaged and not recovering even if they take treatment later.What role does smoking have on asthma?
Smoking does not cause the disease. But active smoking will make it worse and passive smoking is definitely very unpleasant for people with asthma. There are studies to show that the condition of people with asthma sitting next to a smoker in a hotel worsened 12-14 hours after the exposure.
You say there is no cure for asthma. But how long can a person live with asthma?
Yes. There is no cure. But a person with asthma, if treated properly, can live a totally normal lifespan of totally normal quality. But what we cannot say is which children will necessarily go on with it. But if you know that you have asthma at the age of eight and it is troublesome, there is a very high chance of that continuing into adult life. And the difficulty is that sometimes it gets better spontaneously during their teens and people think it is gone, but only to come back in their 20s or 30s. They waste several years taking antibiotics thinking that they have a cold.
What is the kind of research that is going on in asthma?
We already have excellent medicines. Over the last few years, we have had better medicines and a better understanding of how to use them effectively. We have an overwhelming evidence to show that if you teach people how to manage their condition you enhance compliance, reduce dependence upon the doctor, reduce uncertainty and dramatically reduce calls for unscheduled healthcare.
But in terms of being able to switch the disease off, our understanding is much better as we now know which genes are responsible for the development of the adverse mechanisms that give rise to asthma. So, there is always the hope that we shall be able to adjust those genes or switch them off.
We also know that exposure to infections early in life, somehow, protects you from asthma. We need not go around inducing infections in children, but `control infections' may help.What is control infection?
It is vaccination. Instead of having lots of infection in childhood to control asthma, vaccination can play an effective role. We do not have it now. But it is an area of considerable interest.
Some years ago we tried desensitised agents to control hay fever. We gave small doses of the trigger that causes hay fever and built it up slowly so that people built tolerance to the disease. This was given up by many countries as it ran into disrepute. This, however, could be very dangerous for asthma. But as we get better desensitising agents and learn how to use them better, I think there is a possibility that that line of treatment may come back. By this method we can identify the trigger in patients and then switch it off. But we cannot do that at present. However, nothing can detract from the fact that low doses of steroids can transform the lives of millions of asthma patients.
Would the human genome project help in the understanding of asthma?
I think it will help several other diseases before it would help asthma. It may be an avenue for greater understanding of the disease.
Is it because asthma is not a single gene disorder that the human genome project will take time to shed light on the disease?
Yes. You are right. Asthma being a polygene disorder, it may take time for the human genome project to lead to a better understanding of the disease.
Has pharmacological development kept pace with the developments in asthma research?
Pharmaceutical companies and research institutions are doing research and we are grateful for all the new medicines that are coming out. But, looking at it in its totality, it is not new molecules that we need, only better use of the existing ones. It is no good making good medicines available if patients cannot afford them or doctors do not explain to them the reason why they are taking them or if they are not taught to use the inhaler device.
The biggest transformation in India over the next 10 years would be increased use of inhaler steroids and better self-management education and communication between doctors and patients. After 10 years we may have a cure or we might be able to prevent asthma. But now, a large number of people would benefit from using well what we have got.
Should asthma treatment be brought into the public healthcare system?
If you look at countries that have been successful in controlling the prevalence of asthma, all have a central thrust that this is a real issue. The WHO has got a strategy for chronic respiratory diseases, of which asthma is one. Countries such as Finland, Australia, New Zealand and Peru have got significant national initiatives and, despite very high rates of asthma, are beginning to see significant benefits in terms of death rates and hospitalisation rates. In countries like the U.K., there has been lesser government initiative but there has been a very strong professional interest in the disease and very strong activity from national asthma campaigns that have also led to major benefits in asthma. No government can afford to ignore a disease that is affecting a minimum of 3.5 per cent of its population.