Does environmental endotoxin exposure prevent asthma?
- 1Institute for Risk Assessment Sciences (IRAS), Division of Environmental and Occupational Health, Utrecht University, The Netherlands
- 2Centre for Public Health Research, Massey University Wellington Campus, Wellington, New Zealand
- Correspondence to:
Dr J Douwes, IRAS, PO Box 80176, 3508 TD, Utrecht, The Netherlands;
- Accepted 19 September 2001
The evidence as to whether exposure to environmental airborne endotoxin plays a protective or an inducing role in the development of asthma is reviewed. Studies of endotoxin and atopy, endotoxin and asthma, and farming and asthma are considered and, in each instance, a distinction is made between evidence of primary causation and evidence of secondary causation. It is concluded that, although it is plausible that bacterial endotoxin may protect against the development of asthma, there is considerable reason for caution regarding this hypothesis.