Medically unexplained illnesses:
study reveals impacts of illnesses

UPdate Summer 2007

For the first time, Statistics Canada has released information on the numbers of Canadian adults who have been diagnosed with multiple chemical sensitivity (MCS), chronic fatigue syndrome (CFS), and fibromyalgia, along with information about the effects these illnesses have on people’s lives. The three diseases are grouped under the heading of MUPS, medically unexplained physical symptoms. Over a million Canadians, 5% of the population over the age of 12, have been diagnosed with at least one of the three illnesses. 1.3% of the population suffers from chronic fatigue syndrome, 1.5% from fibromyalgia, and 2.4% from multiple chemical sensitivity.
Chronic fatigue syndrome 1.3%
Fibromyalgia 1.5%
Multiple chemical sensitivity 2.4%


Women were twice as likely as men to report each of the three conditions. The numbers increase with age. In the 12-24 year old age group only 1.6% of people reported having one or more of these illnesses. In the 45-64 year age group, rates rose to 6.9%.

People with all three illnesses were dependent on others for help in basic activities of daily life to a far greater degree than the general population. Over one quarter of the respondents, twenty-seven percent, required help with activities such as preparing meals, doing everyday housework, getting to appointments and running errands. Eight percent reported that they needed assistance with activities such as bathing, dressing, eating taking medication and moving about inside the house. In the general population, 7% of people need some help while 2% need help with basic activities. This demonstrates the need for support services such as home care for people living with CFS, MCS and fibromyalgia.

The research revealed that living with chronic fatigue, fibromyalgia or chemical sensitivity significantly affects people’s sense of well being. Twenty three percent were dissatisfied with their lives, compared with 8 percent of the general population. Fifteen percent (compared with 4% in the general population) considered their mental health as fair or poor. Substantial proportions of people with MUPS had a negative perception of their physical health. Researchers also found that more people with MUPS suffered from major depressive disorder, panic disorder, social anxiety disorder, agoraphobia or bi-polar 1 disorder than among the general population. The report notes, “Some research suggests that the stress of having unexplained symptoms may lead to mental health problems - in many cases MUPS precedes psychiatric symptoms.”

Data was drawn from the 2002-3 Canadian Community Health Survey, which sampled 130,000 people across the country.

The study does not reflect the actual numbers of people who live with CFS, MCS and fibromyalgia. It reflects only the numbers of people who have been diagnosed with these illnesses. All three disease are likely to be under diagnosed for a variety of reasons, among them lack of medical training in identifying the diseases, as well as lack of training in how to treat patients who have these illnesses.

In recognition of this problem, the US Center for Disease Control launched a major publicity and education campaign in 2006 to improve recognition and diagnosis of CFS among physicians and the general public.

In relation to MCS, three US surveys have found that the number of people who reported being allergic or unusually sensitive to everyday chemicals was between 4 and 8 times greater than the number who had been diagnosed with chemical sensitivity.

A 1999 survey conducted by the New Mexico Department of Health, (Voorhees), found 16 percent reported being sensitive to chemicals, while only 2% had been diagnosed with MCS. Two percent reported losing a job or career because of the illness. A California Department of Health study of California adults [Neutra, Kreutzer and Lashuay,1999] found that 15.9% reported being allergic or unusually sensitive to everyday chemicals, and 6.3% had been diagnosed with chemical sensitivity. A study in Atlanta, Georgia (Caress and Steinemann, 2003) found that 12.6% of people in the Atlanta metropolitan area reported that they were “unusually sensitive to everyday chemicals like those in household cleaning products, perfume, detergents, insect spray and things like that. ” Close to 3% had been medically diagnosed.