Study type: Epidemiological study (observational study)

Comparing non-specific physical symptoms in environmentally sensitive patients: prevalence, duration, functional status and illness behavior. epidem.

Published in: J Psychosom Res 2014; 76 (5): 405-413

Aim of study (acc. to author)

A health survey of adults in the Netherlands was combined with the electronic medical records to assess non-specific physical symptoms in people with general environmental sensitivity (GES) and idiopathic environmental intolerance attributed to electromagnetic fields (IEI-EMF) and to determine differences in functional status and illness behavior.

Further details

To assess IEI-EMF, the participants were asked whether they were sensitive to mobile phone base stations, mobile phones, wireless internet or to electrical devices (e.g. domestic appliances).
A list of nine items (chemical substances, smells in general and in relation to scented detergents, noise, light, various materials, color, temperature changes and cold or warm environment) was used to assess general environmental sensitivity (GES) (also called idiopathic environmental intolerance (IEI).
Functional status was assessed by general practitioners-registered prevalence of prescriptions related to painkillers, tranquilizers (benzodiazepines) and antidepressants. For general health status and psychological distress, participants completed the General Health subscale of the RAND-36 Health Survey questionnaire. Sleep quality was assessed using a 10-item version of the Groningen Sleep Quality Scale.

Endpoint/type of risk estimation

Type of risk estimation:

Exposure

Assessment

Population

Study size

Type Value
Total 13,007
Participants 5,933
Evaluable 5,789
Statistical analysis method:

Conclusion (acc. to author)

Overall, 202 (3.5%) participants and 514 (8.8%) participants met the criteria for the IEI-EMF and GES group respectively, while the rest of the participants (n=5073) formed the control group. Seventy-seven (38%) of participants in the IEI-EMF group also met the criteria for GES.
There was a higher prevalence of symptoms and medication prescriptions and longer symptom duration among people with sensitivities. Moreover, participants with GES were about twice as likely to consult alternative therapy compared to the control group; those with IEI-EMF were more than three times as likely. Increasing number and duration of self-reported non-specific physical symptoms were associated with functional impairment, illness behavior, negative symptom perceptions and prevalence of GP-registered non-specific physical symptoms in the examined groups.
Even after adjustment for medical and psychiatric morbidity, environmentally sensitive individuals experienced poorer health, increased illness behavior and more severe non-specific physical symptoms. The number and duration of self-reported non-specific physical symptoms are important components of symptom severity and are associated with characteristics similar to those of non-specific physical symptoms in primary care.
The authors conclude that the substantial overlap between the sensitive groups strengthens the notion that different types of sensitivities might be part of one, broader environmental illness.

Study funded by

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