Prof. John F. Price is one of the most distinguished researchers in the field of paediatric respiratory medicine today and has contributed substantially to the advancement of knowledge in this field.

For over a decade, he has been a Professor of Paediatric Respiratory Medicine and Head of the Department of Child Health at King's College. He has also served as the Chairman of the Women and Children division at the same hospital.

Prof. Price has been a consultant paediatrician at the King's College Hospital, London since 1979, the year in which he started a special clinic for children with respiratory disorders. Ten years later, he set up a Cystic Fibrosis Clinic that currently looks after 200 children with the disease.

He has more than 160 publications to his credit including chapters, editorials and review articles. His research interests include asthma and the impact of its treatment in children below the age of five. He was responsible for the paediatric aspects of a national prospective study titled ‘Long term efficacy of early introduction of inhaled steroids in asthma' that was funded by the NHS Health Technology Assessment Programme. His recent interests include the role of the immune system in children with recurrent wheezing induced by viral infection.

Prof. Price has been a recipient of the Rhodes Education Scholarship. He is active in several bodies such as the European Paediatric Respiratory Society, the European Respiratory Society, the National Asthma Campaign in the UK and the Royal College of Paediatrics.

He was in India in January 2003 as a special invitee at PEDICON 2003.

Throughout the world in the last 30 years there has been a steady, relentless increase in the prevalence of childhood asthma. According to the 50-nation International Study of Asthma and Allergies in Childhood (ISSAC):

• Asthma is a very common condition.
• Its prevalence varies widely from country to country.
• At the age of six to seven years, the prevalence ranges from 4 percent to 32 percent. The same range holds good for ages 13 and 14.

The UK has the highest prevalence of severe asthma in the world. (Fig. 1)

 

In India, a questionnaire-based study measured the prevalence of asthma in nine randomly selected Delhi schools. The prevalence of current asthma was found to be 11.9 percent. Assuming Delhi represents the whole of India, this means there are 40 million children in India, who suffer with asthma. (Fig. 2)

 

A longitudinal prospective study was conducted in UK in 1958. A large cohort of babies, all born in the same week, were gathered and followed during their growth into adulthood. Wheezing and asthma were observed as they grew. The study showed the following results:

• At age seven, one half of these children had onset of wheezing, diagnosed as asthma
• By age 11, the wheezing had fallen below 20 percent
• During mid-teens and early 20s, it fell to 10 percent
• By 33 years, relapses occurred after prolonged remission of childhood asthma (Fig. 3)

This epidemiological study looked at asthma overall and did not categorise the cases into mild, moderate, or severe.

 

Another study initiated by Dr. Harvard Williams in 1964 in Melbourne overcame these drawbacks. The study covered the age group of 10 to 35 years. Lung function tests were conducted and the children were categorized into four groups:

• Those who had very mild wheezing and only occasional wheezing episode.
• Those who had wheezy bronchitis.
• Those who clearly had asthma.
• Those who had severe asthma.

Tests revealed that in children with mild asthma, lung function improved and early adulthood was normal. However, in children with severe asthma, lung function remained abnormally low even after they grew up.

The above graph (Fig. 5) shows the lifetime changes in lung function.

In normal, healthy individual lung function increases up to 20 years of age. Then it declines slowly. In a patient of asthma, maximum lung function is not achieved. Even if the natural decline in lung function is at a normal rate, it will remain lower than that of a normal, healthy person.

The children participating in the Melbourne study were 10 years of age in 1964 and did not get modern treatment. So, what happens to children who get asthma at the age of 10 and who do not get proper, modern treatment? (Fig. 6)

In Figure 6, there are four categories

• Mild wheeze
• Wheezy bronchitis
• Asthma
• Severe asthma

The vertical axis represents the group of children between the age of seven and ten years. The horizontal axis shows the outcome in their mid-life. The outcome is represented as percentage of subjects with:

• No asthma.
• Episodic asthma.
• Persistent asthma.

The graph shows that 70 percent of those who had mild wheeze completely grew out of their asthma by the age of 42 years. Severe asthmatics had asthma throughout their lives with half of them continuing to suffer from persistent asthma.

 

Prof. Martinez and his colleagues studied a cohort of over 1000 newborn babies and followed them very closely throughout their childhood. They paid special attention to respiratory infection & wheezing illnesses.

In Group I, they observed that many children who had started wheezing in the first three years of life stopped wheezing by the age of six or by school age. Prof. Martinez called them transient wheezers. They exhibited the following characteristics:

• They wheezed only when they had viral infections.
• Lung function tests at birth showed narrow airways which were not associated with allergy or atopy. But there was a strong association with maternal smoking during pregnancy.

So the hypothesis was that smoking during pregnancy interfered with the normal development of the lung airways. These tended to be smaller at birth but grew larger with age. By age six, the airways were significantly large and the children were no longer wheezing. In the study, this represented 40 percent to 60 percent of pre-school children who wheezed.

In Group II, children had persistent wheezing that was clearly associated with allergy. They wheezed till the age of eleven. Other important characteristics displayed by this group included:

• 60 percent had started wheezing before the age of 3.
• 80 percent before the age of 6.

These children were recognized as children with persistent atopic asthma. Their asthma developed before they went to school and in many of them,
before they were 3.

In Group III, children had persistent symptoms but were not atopic. The cumulative prevalence increased in the first six years but then started to decline. So, the prognosis in these children was much better although they behaved in very much the same way as atopic asthmatics during the pre-school years.

Looking at all three groups (Fig. 7) their ages overlap and the prevalence is about the same. That poses a challenge to distinguish these children and to predict those who will go on to have persistent wheezing. Those who had persistent wheezing with atopy nearly got over their wheezing in their teens. Those in whom persistent wheezing was not associated with atopy often remitted at school age. This group represented 50 percent to 60 percent of pre-school wheezers.

 

A prospective study conducted in 1995 investigated the factors affecting wheezing before the age of three and their relation to wheezing at age six. The study revealed that the majority of infants with wheezing had transient conditions associated with diminished airway function at birth. They were also at increased risk of suffering from asthma or allergy later in life. In a substantial minority of infants, however, wheezing episodes were probably related to predisposition to asthma. Such children already had elevated serum IgE levels during the first month of life and had substantial deficits in lung function by the age of six. (Fig. 8)

 

 

In a study carried out in children less than two years of age with early persistent atopic wheezing, bronchoalveolar lavage was done to assess inflammation. Fluid was taken from the airways to detect inflammatory cells. Data obtained from atopic wheezing children was compared with that from children without wheezing. There were increased lymphocytes, neutrophils and eosinophils in wheezing children compared to non-wheezing children. Thus, in wheezing children airway inflammation was apparent by the age of two.

Perhaps the outcome of this study gives us a hint about when to really start anti-inflammatory therapy. (Fig. 9)

• Family history of atopy
• Eczema
• Allergic rhinitis
• Severe symptoms with hospital admission
• Exposure to tobacco

 

Three factors have a significant influence on the long-term outcome of childhood asthma:

• Avoiding allergens
• Anti-inflammatory therapy
• Tobacco smoke