Asthma: environmental and occupational factors.

Area of Science:

• Pediatric Allergy and Immunology
• Environmental Epidemiology

Background:

• Asthma presents diagnostic challenges due to its variable childhood onset, remission/relapse patterns, and difficulties in operationalizing clinical features.
• Observed increases in asthma prevalence in Westernized countries suggest significant environmental influences on disease causation, alongside acknowledged genetic factors.

Purpose of the Study:

• To review current etiological research on asthma, focusing on environmental determinants.
• To evaluate the role of allergen exposure and early-life microbial contact in asthma development.
• To assess the 'hygiene hypothesis' as an explanation for asthma's geographical and temporal distribution.

Main Methods:

• Literature review of recent etiological research in asthma.
• Analysis of geographical and temporal trends in asthma incidence.
• Examination of studies investigating allergen exposure and early microbial contact.

Main Results:

• Asthma's complex etiology involves both genetic predisposition and strong environmental influences.
• Research highlights the potential impact of allergen exposure and early microbial interactions on childhood allergy development.
• The 'hygiene hypothesis' provides a framework for understanding asthma's distribution but requires more robust evidence.

Conclusions:

• Asthma etiology is multifactorial, with environmental factors playing a crucial role.
• Further research is needed to validate the 'hygiene hypothesis' and elucidate the mechanisms linking early life exposures to asthma.
• Understanding these factors is critical for developing effective prevention and treatment strategies for childhood asthma.