Professor Olf Herbarth from the Faculty of Medicine of the University of Leipzig, Germany, gave a lecture at the Lodge recently on "Trends in Environmental Health Risk".  He works at the Helmholtz Centre for Medical Sciences.

Olf has been associated with the Wessex Institute of Technology (WIT) for a long time and has participated in many different meetings as a member of the International Scientific Advisory Committee and as a keynote speaker.

The problem he discussed during his lecture was the need to relate predictive computer models with experimental data.  He also referred to an increase in the occurrence of a series of diseases such as asthmas and allergies.

Modern allergies were believed to be related to our current hygienic environment.  However, this idea is no longer accepted and there is now concern that the main problems are due to indoor exposure, the role of chemicals and the combination of different types of exposure.

Environment-related diseases are now widely prevalent.  They may be due to non-toxic, as well as toxic exposures.  Allergies are associated with the non-toxic exposures and can be caused by a chemical acting as a catalyst to start the process. Asthma, eczema and hay fever are all related to environmental exposure.

Several studies were carried out by the Leipzig Research Group involving approximately 6,000 children and 18,000 clinical tests.  Exposure assessments were carried out for each child.

Indoor exposure due to chemicals and aerosol particles is now understood to be a very important cause of allergy.  The problem is how to assess the exposure.

One of the problems investigated is that of mould, which can occur outside (summer) or indoors (winter).  Other substances of interest in the research were VOC (Volatile Organic Compounds) which produce irritation in the respiratory system.  There is a large number of VOC and their concentrations are large indoors.  The rate of concentration is 1 to 10 between outdoor and indoor, which represents a much larger exposure ratio, taking into account the amount of time people spend indoors.  The main problem is the high concentration in apartments, public places, hospitals, etc.  The effect is increased by redecoration carried out in dwellings, which is particularly common during pregnancy, prior to a baby being born.

The more recent study carried out by Olf aimed to determine the influence of VOC on respiratory diseases and allergies.  This demonstrated the high risk associated with indoor versus outdoor exposure.  Mould was also proven to result in airway diseases and allergies.

VOC are the result of painting, floor coverings and new furniture.  Children who have been exposed to these types of compounds, exhibit almost double the prevalence of allergy symptoms and eczema.  The effect is similar to that of children growing up in a smokers environment.  If anything, indoor exposure due to redecoration has proved to be more damaging than a smoking environment, albeit acting over a shorter time. Chemical indoor exposure due to decorating plays an important role in allergies and respiratory diseases.

Another problem is the presence of particles in the air, particularly nanoparticles.  The first question is, what type of particles cause bad effects?  Until now, the concentration levels proposed have been based on outdoor particle concentration studies while most people spend most of their time indoors, although the concentration tends to be smaller indoors than outdoors.

Particles have cardiovascular effects, with increased numbers of emergency unit cases during periods in which the concentration of smaller particles increases.  These results, which have been reported in the USA, were confirmed by the Leipzig group studies.

Olf referred at the end to the increase in hygiene in the last 80 to 100 years.  This means that modern man does not have the chance to develop defences that come out of infections.  What Olf found by looking at infection versus allergy is that certain types of infections are a protection against allergies.

In conclusion, immature immune systems led to higher allergic risk than mature immune systems.  There is, however, a series of open questions, such as how to determine the source related exposure pattern; and how to account for the combined efforts of noxious chemicals and microbiological substances.  We also need to learn how to model exposure pathways and realistic exposure scenarios.  It is also necessary to determine chronic low dose effects versus acute effects.

It is important, Olf stressed, to learn from these epidemiological studies in order to prevent the many problems confronting modern man.

The excellent presentation was followed by numerous questions.