Prevalence of ES from the CHRC report

Full report can be viewed at: The Medical Perspective on Environmental Sensitivities
http://www.chrc-ccdp.ca/research_program_recherche/esensitivities_hypersensibilitee/toc_tdm-en.asp

Diagnostic criteria are used by physicians to identify a health condition in individuals, and by researchers to determine the proportion of the population experiencing the condition severely enough to seek medical care. Some people with environmental sensitivities are less severely affected and may not seek care. This proportion of individuals in the population is generally investigated with more general questions about reactions to perfumes or other everyday chemicals.

In January 2007, Statistics Canada reported that 5% of Canadians (1.2 million people) suffer "medically unexplained physical symptoms," including multiple chemical sensitivity, fibromyalgia and chronic pain.9

According to Statistics Canada’s 2003 National Population Health Survey (N=135,573),b the prevalence of doctor-diagnosed multiple chemical sensitivities was 2.4% in people aged twelve or older,9 and 2.9% in people thirty years of age or older.10 The 2005 National Survey of the Work and Health of Nurses revealed that 3.6% of all Canadian nurses experienced chemical sensitivities (N=18,676).11 Prevalence in the general American population has been reported to range from 3.1% doctor-diagnosed multiple chemical sensitivity in Atlanta, Georgia (N=1,582)12 to 6.3% doctor-diagnosed chemical sensitivity in a large California survey (N=4,046).13
Many more people experience less severe sensitivities. Self-reports of heightened sensitivity (feeling ill) on exposure to "everyday " chemicals in American populations ranges from 11% of 1,057 participants in a US national survey 14 and 16% in California,13 to 33% in rural North Carolina.15 It is unclear to what extent people experiencing less severe intolerances are at an increased risk of developing full-blown, debilitating environmental sensitivities. However, recent studies have revealed genetic links to sensitivities,16-22 and biochemical differences between people with sensitivities and "control" populations.23 Clinical experience shows that increasing chemical exposures are associated with increasing symptoms and reports of sensitivity spreading to more incitants.3,24