RISK FACTORS FOR ALLERGIC DISEASE

Sports and Allergies

• Moderate and controlled exercise is beneficial for allergic subjects and should be part of their management.

• Vigorous exercise may trigger or exacerbate several allergy syndromes such as bronchospasm, rhinitis, urticaria-angioedema and anaphylaxis. 

• Allergy diagnosis should be part of the routine medical examination in all professional and amateur athletes, in order to adopt adequate preventative and therapeutic measures for controlling the disease, while avoiding potential symptoms occurring on exercise.

The Potential of Genetics in Allergic Diseases 

• Allergic disorders are heterogeneous and involve important gene-environmental interactions. 

• Human genetics has a role to play in understanding susceptibility for disease onset, phenotypes and subphenotypes, severity, response to treatments and natural history. 

• Although candidate gene association studies have provided some insight into the role of genes in disease susceptibility, most new information is emerging from hypothesis-free approaches such as genome-wide association studies. 

• Many early gene association studies were under-powered and the results have not been confirmed in different populations. 

• Genetic factors that influence the expression of atopy are different from those that influence disease manifestations or its severity in specific organs. 

• Poymorphism of a single gene usually accounts for only a small proportion of the disease phenotype. 

• Epigenetic influences involving multiple mechanisms, including methylation of CpG islands in gene promoters, histone acetylation, phosphorylation and methylation and a large number of micro RNAs, explain a proportion of the gene-environmental interactions and trans-generational effects. 

• The genetic epidemiological observations for specific candidate genes in atopy and allergic disease require careful replication, enhanced by international collaboration and the availability of large, well-characterized casecontrol populations for genotyping. The only way to achieve this is to promote greater cooperation among researchers and create multidisciplinary teams including researchers from academia, industry and clinical practice.

Allergens as Risk Factors for Allergic Diseases

• Sensitization (IgE antibodies) to foreign proteins in the environment is present in up to 40% of the population.

• Such sensitization is strongly associated with exposure for proteins derived from pollens, molds, dust mites and cockroaches. 

• For asthma, rhinitis and atopic eczema there is a strong and consistent association between disease and sensitization. 

• The association between sensitization to grass pollens and symptoms of hay fever occurring during the grass pollen season provides strong evidence for a causal role of grass pollen in the disease.

Environmental Risk Factors: Indoor and Outdoor Pollution 

• Epidemiological studies show that indoor and outdoor pollution affects respiratory health, including an increased prevalence of asthma and allergic diseases. 

• Outdoor pollution is associated with substantial mortality; for example in China, outdoor pollution is associated with more than 300,000 deaths annually. 

• Conservative estimates show that exposure to indoor air pollution may be responsible for almost 2 million deaths per annum in developing countries. 

• Exposure to outdoor/indoor pollutants is associated with new onset of asthma, asthma exacerbations, rhinitis, rhinoconjunctivitis, acute respiratory infections, increase of anti-asthmatic drug use, and hospital admissions for respiratory symptoms. 

• Abatement of the main risk factors for respiratory disease and, in particular, environmental tobacco smoke, indoor biomass fuels and outdoor air pollution, will achieve huge health benefits.