National prevalence of asthma and chemical hypersensitivity: An examination of potential overlap

Objective: The objective of this study was to investigate the linkage between asthma and chemical hypersensitivity. Methods: The authors conducted a population study with a random sample of 1057 geographically weighted cases to determine the Prevalence of both asthma and chemical hypersensitivity in the American population and to explore their co-occurrence. Results: A total of 14.1 % of the respondents reported being diagnosed with asthma and 11.2 % reported a hypersensitivity to chemicals. Of those with asthma, 27.2 % also reported being hypersensitive to chemicals and 7.4 % reported also being diagnosed with multiple chemical sensitivities (MCS). Of those diagnosed with MCS, 42 % reported also being diagnosed with asthma. Additionally, 29.7% of those with asthma said air fresheners caused breathing difficulties, and 37.2 % found scented products irritating. Conclusions: The results indicate that there is significant overlap between some forms of asthma and chemical hypersensitivity.