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One of the important ultimate goals still
is to learn enough about the causes of childhood diabetes
to be able to prevent it. |
More than 10 million people in Europe have diabetes. Some do
not develop it until middle age but one particularly severe form usually
starts in childhood. Affected children suffer from this illness throughout
their lives. The EURODIAB projects are tackling this major health
problem by combining scientific skills, data and observations from
all over Europe. Their results show that the incidence of childhood
diabetes varies considerably over time and between different areas
of Europe. They also illustrate how disease can result from the complex
interplay of genetic and environmental factors.
Childhood diabetes cannot be controlled by
diet. Affected children need to receive insulin therapy and this can
mean regular daily injections. Such treatment allows diabetics to
lead full and active lives but there are two problems. Firstly, childhood
diabetes is a problem for life: there is no cure and long-term diabetics
often suffer complications such as eye or kidney problems as they
get older. Secondly, the incidence of childhood diabetes is increasing
but no one knows for sure why.
Research into diabetes has a long history but the first major pan-European
studies into the disease began in 1985. One of the important ultimate
goals was, and still is, to learn enough about the causes of childhood
diabetes to be able to prevent it. Work in the first three years formed
the pilot phase of a concerted action. Diabetes of all types is a
problem in every country in Europe and developing a good network between
as many of the specialists involved as possible was a priority goal.
Once co-operation between different groups was working well, effective
scientific studies launched as a series of projects under the EURODIAB
label could really get going.
Childhood onset type 1 diabetes in Europe
Age group 0-14 years Standardised incidence rate (darker
shades of red are a higher incidence)
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Studying 17 million children
The first project, EURODIAB (The Epidemiology and prevention of
Diabetes), was set up with a broad brief to expand the research
network. It then aimed to use this to study the incidence of childhood
diabetes across Europe, the complications the disease caused in
later life, and its general social impact. When this project was
completed in 1992, all partners agreed that the research network
was fully operational and published their findings in the prestigious
medical journal, The Lancet. Anders Green, co-ordinator of EURODIAB
summarised the main results: "Data was collected from 24 study regions
across Europe and Israel, involving a study of 16.8 million children.
Incidence varied widely between the regions, ranging from 42.9 annual
cases per 100 000 in Finland and 30.2 per 100 000 in Sardinia to
4.6 cases per 100 000 per year in northern Greece. Generally, rates
were higher in northern Europe compared to the south, but there
were exceptions. Eastern European countries tended to have very
low rates."
A complex picture
In 1993, a new phase, EURODIAB ACE (Aetiology of childhood diabetes
on an epidemiological basis), began. Its aim was to use the, by
now, well-established network to research the nature of childhood
diabetes in detail using genetic and immunological methods. The
ACE study set out to monitor the frequency of diabetes in children
and to describe the trends in incidence of the disease throughout
Europe. This study also included teams of scientists from Central
and Eastern Europe - in total about 40 different groups worked together,
representing a study population of almost 30 million children.
The results were interesting but they painted a complex picture.
Some genetic markers were found much more often in children who
developed diabetes, suggesting that these might be genes that increase
susceptibility. At the same time, the researchers found that some
genes seemed to correlate well with the diabetes incidence across
Europe. Moreover, the incidence in individual countries was changing
quite quickly and this could not be explained by genetics. The evidence
pointed to interplay between genes and the environment and that
this interplay may differ between populations.
Changing trends
The current phase of the project, EURODIAB TIGER (Type I Genetic
Epidemiology Resource) is taking the work forwards to gain some
important clues about which causal factors are most important. TIGER
scientists are currently collecting material from 2000 patients
and their immediate relatives. These samples will be screened and
analysed for the distribution of specific genetic and immune markers
in conjunction with the concerted action, PARADIGM. This provides
the centralised facility that does all the laboratory work. Anders
Green comments, "We now know for certain that there is an annual
increase in the incidence of childhood diabetes in most countries
in Europe. At the moment, the problem is most serious in Central
and Eastern Europe. Only a few years ago, rates here were low but
they are now increasing rapidly. In Northern Europe the rates at
which new cases are appearing may now be reaching a plateau. We
cannot yet say for certain what is happening. When we have analysed
the data and know more about the genetic factors involved, the next
step will be to couple this knowledge with information on the environmental
factors - lifestyle, diet, virus infections, for example. My hope
is that the huge collaborative network that we have set up will
continue. It is a valuable resource that must not be wasted and
it is a strong support mechanism, particularly for the teams in
Central and Eastern Europe. They will need the network to help cope
with the growing diabetes problem in their countries for the foreseeable
future."
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