Burden of Respiratory Disease in Childhood 2003/2
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Introduction
The prevalence of long-term respiratory illness in children is
greater than that from all other chronic conditions combined (table
1). Respiratory disease (both acute and chronic) accounts for
20% of weekly GP consultations, 15% of hospital admissions and
8% of deaths in childhood. Among respiratory illnesses, acute
viral upper respiratory infections and asthma attacks are the
commonest with asthma also being the most common chronic disease
in children. A significant proportion of drug costs are also generated
by childhood respiratory illnesses. Morbidity is substantial including
time spent symptomatic, school loss and work absence in the parents
of young children.
Table 1: Prevalence
of long-term illness and percentage of weekly GP consultations,
annual hospital admissions and annual deaths in children by broad
underlying cause groups.
GP consultations
Among children, about a fifth of all GP consultations are classified
as resulting from the respiratory system with another 2% registered
as symptoms and signs involving respiratory disease (see also
factsheet 95/3). Across all age
groups, the greatest rate of consultations is for the common cold
and other upper respiratory tract infections (figure 1a). Bronchiolitis
is the most common illness of the lower respiratory tract in the
under 1 year olds and acute cough or bronchitis in the 1-4 year
olds (figure 1b, note the differing scales). Asthma is the second
most common respiratory cause over all ages (3% of all consultations)
with a weekly incidence rate of GP consultations of almost 1 per
1000 population, in the 1-4 year olds. In the older age group
the rate of consultation for hayfever and allergic rhinitis is
comparable with that for asthma.
Figure 1: Mean weekly
incidence rate of GP episodes for respiratory diseases in children,
1999-2001
Weekly acute asthma consultation rates rose steeply in earlier
decades (figure 2) but have fallen rapidly more recently. The
prevalence of GP treated asthma in 5-15 year olds shows only a
slight increase over the years 1994-1998 (figure 3). The rate
in 0-4 year old children has not changed and in both age groups
asthma prevalence is higher in boys compared with girls (13% in
boys compared with 10% in girls in 5-15 year olds and 10% versus
7% in 0-4 year olds).
Figure 2:
Mean weekly incidence of asthma GP episodes in children, England
& Wales, 1976-2001
Figure 3:
Prevalence of GP treated asthma in children
The decline in new episodes of acute asthma in general practice
parallels the decline in hospital admissions. This, despite the
absence of a decline in GP treated prevalence rates, may indicate
improved treatment.
Hospital Admissions
In 2000/01, respiratory disease accounted for 15% of all children's
hospital admissions in England. Almost a third of all lower respiratory
admissions in children and 40% in the 1-4 year olds were due to
asthma (table 2). Croup and pneumonia are important causes in
the under 5 year olds.
Table 2: Hospital
admission rates for lower respiratory disease in England, 2000/01
Acute bronchiolitis is the second most common cause for admission
in all children. This is a disease limited to very young children
with a hospital admission rate of 3611 per 100,000 in the under
1 year olds. There is a marked seasonal variation in these admissions
(see factsheet 93/3). Bronchiolitis peaks in winter and poses
a considerable burden on all health care resources, particularly
GP time and in-patient beds.
There has been a rapid downward trend for asthma admissions during
the last decade (figure 4). This contrasts with the rising trend
seen over the 1970s and 1980s (see fact sheet 96/2). During this
same period, admissions for acute bronchitis have also fallen,
from 18 to 7 per 100,000, whilst those for acute bronchiolitis
and other acute lower respiratory tract infections have remained
broadly stable.
Figure 4:
Trends in admission rates for respiratory conditions in 0-14 year
olds, England 1991-2000
Neonatal admissions are largely the consequence of prematurity.
Many of these have associated respiratory disease (N=23,640, 4200
per 100,000 livebirths in 2000) of which 7400 were for respiratory
distress of the newborn.
Mortality
Neonatal Deaths
There were 2335 neonatal deaths in England and Wales in 2000 with
diseases of the respiratory system accounting for one third of
these (131 per 100,000 livebirths). However, diagnostic labels
are not always specified; approximately 50% of neonatal respiratory
deaths were classified as "other conditions" (figure
5). Sixteen percent were from respiratory distress syndrome associated
with prematurity while congenital anomalies, including diaphragmatic
hernia, accounted for 14% of respiratory deaths.
Figure 5: Number
of respiratory related deaths in neonates, England & Wales
2000
Children's Deaths
Pneumonia is certified as the cause of four times more deaths
in children aged 0-14 years than asthma (figure 6). Three-quarters
of deaths from pneumonia occur under 4 years of age. In the year
2000, 13 (60%) of the total of 22 asthma deaths in England and
Wales occurred in children aged 10-14 years. Difficulties in treatment
adherence in this age group may be contributory.
Figure 6: Number
of deaths in children due to respiratory causes (excluding neonates),
England & Wales 2000
Since 1986 deaths in neonates (under 28 days) have been classified
separately and not included in children's deaths. Time trends
from 1986-2000 are shown in figure 7. The most striking observation
is the decline in deaths from pneumonia which continued until
1992 when a change in the rules on coding final cause of death
may have raised the number classified as pneumonia. Rates from
1992-2000 have remained static. Mortality rates for many respiratory
conditions have declined, including bronchiolitis, cystic fibrosis
and bronchitis. A change in disease labelling may have contributed
to, though does not explain, the fall in rates for bronchitis.
Mortality rates from asthma increased in the early 1980s, declined
from 1990 and have shown little change since1993.
Figure 7: Mortality
rates from respiratory diseases in children 0-14 years, England
& Wales 1986-2000
Other conditions
Tuberculosis
TB notification rates (including extra-pulmonary disease) in children
in England and Wales fell during the 1980s (figure 8). After a
transient peak in 1993 they have shown little fluctuation and
stood at 4.6 per 100,000 population (448 notifications) in 2001
in 0-14 year olds. Rates in London showed a similar trend until
1994 for all children's age groups. Since then, the rates have
risen sharply peaking in 1998 with 13.8 notifications per 100,000
0-14 year olds. In 2001 the London rate was 11.0 per 100,000 (150
notifications), more than double the national rate. This recent
increase in the capital could be due to increased deprivation,
immigration, travel or incidence of HIV.
Figure 8: Tuberculosis
rates in children 0-14 years, London and England & Wales 1982-2001
Cystic Fibrosis
There are approximately 3500 children aged 0-16 years with CF
in the UK. Children aged between 10-15 years comprise the largest
group but beyond this age, the numbers decline (figure 9). There
are fewer than 700 patients over the age of 30 years. This distribution
of ages is expected to change over the next 20 years, reflecting
improvements in survival. Current median survival is about 30
years but children born in the last decade can expect a median
survival of about 40 years. Much of the improvement in survival
can be attributed to better nutrition and treatment.
Figure 9: Cystic
fibrosis patients by age and sex, UK 2001
Summary
- Respiratory conditions are the commonest chronic disease group
in children.
- They account for approximately 20% of GP consultations and
15% of hospital admissions.
- Childhood asthma is the most common chronic illness, and overall
in childhood, accounts for more admissions than any other single
condition.
- In the under 1 year olds, however, bronchiolitis is the most
common cause for admission.
- Mortality from respiratory disease is approximately 8% of
all childhood deaths
- Mortality rates have fallen for most respiratory diseases
over the last 2 decades whilst those due to asthma remain largely
unchanged.
Sources
Health of Young People, England
1995-97.
RCGP Weekly Returns Service
Hospital Episode Statistics
ONS Mortality Statistics
General Practice Research Database
Communicable Disease Surveillance
Centre
Cystic Fibrosis Trust
We would like to thank Dr Anne Christopher and Dr Suzanne Crowley
for preparing this factsheet.
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