There are many risk factors for asthma. Identifying the significance of a guilty exposure must be set in the context of competing risk factors. Causation research should be corrected for known risk factors. Childhood asthma increases the risk of adult asthma.
MM Haby et al. Thorax. August (2001) Vol.56 #8 p 589.
Risk factors and their statistical strengths were reported in this paper.
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