What initiates chemical intolerance (CI)?

Toxic molds, fossil fuels, antibiotics linked to chemical intolerance.


Chemical Intolerance (CI) is a growing global public health issue characterized by symptoms such as fatigue, headaches, weakness, rash, mood changes, musculoskeletal pain, gastrointestinal and respiratory issues, and difficulties with attention and concentration, often referred to as “brain fog.”

The study, led by researchers from The University of Texas Health Science Center at San Antonio, discovered that longer antibiotic courses were linked to an increased risk of CI.

The new study found that the odds of respondents reporting CI nearly tripled with each additional initiating exposure.

The new study explains the two-stage disease process known as TILT (toxicant-induced loss of tolerance). The survey asked 10,981 people to state their self-perceptions about the events that began the downward spiral through TILT and into chemical intolerance.

Senior author Claudia S. Miller, MD, MS. Miller, the physician-researcher who first proposed TILT in 1996, is professor emerita of family and community medicine at the health science center (also called UT Health San Antonio), said, “TILT can develop rapidly, for instance, after a pesticide exposure, or gradually if someone is working or living in a setting such as a moldy building.” 

He said, “Initiating events commonly go unrecognized and unreported, leaving triggers and symptoms as the only documented components. This has thwarted our understanding of the actual causes of TILT.”

The Personal Exposure Inventory, an 80-question online survey, was completed by participants. It includes information about people’s medical conditions and personal exposures, such as antibiotic use.

Miller created the Quick Environmental Exposure and Sensitivity Inventory (QEESI) 25 years ago to measure chemical intolerance. Mold was stated as the initial event by 17.5% of respondents who met the criterion, making it the most frequently mentioned initiating event on the Personal Exposure Inventory. 

Biostatistician Raymond F. Palmer, Ph.D., co-author of the paper and professor of family and community medicine at UT Health San Antonio, said, “In recent years, global warming has led to more rainfall, floods, hurricanes, roof leaks and water intrusion, resulting in increased mold growth indoors.” 

Mold was followed by pesticide exposure (mentioned by 13.8% of respondents), medical/surgical treatments (12.6%), remodeling/new building (12.0%), fires/combustion products (7.2%), and breast implants (1.8%), in that order.

The researcher said, “Our search for the underlying causes of CI represents a much-needed addition to the CI/TILT literature, whose principal focus has been on triggers that elicit CI symptoms from day to day with no attempt to determine what initiated TILT.” 

She said, “Taken together, our data support the idea that the person who reports multiple symptoms, multiple intolerances, and recurrent infections, as well as a history of exposure events, is sharing a cohesive narrative, one that points to physiological (as opposed to psychosomatic) explanations of their oft-confusing complaints.” 

In the end, The researchers encourage practitioners who visit patients with medically unexplained symptoms to consider giving the QEESI. 

Miller said, “TILTed’ individuals who report brain fog, memory, mood, and concentration difficulties often receive referrals to psychiatrists, psychologists, or social workers who explore their psychosocial environments but do not ask about changes in their actual — physical and chemical — environments, If initiating exposures such as pesticides, toxic mold, implants, and combustion products are not stopped, sensitivities can spiral out of control.”

The researcher concluded that future prevention initiatives for CI/TILT should focus on reducing exposures to pollutants from pesticide usage, new construction, and mold despite the difficulty in avoiding specific directions.

The Marilyn Brachman Hoffman Foundation and Marilyn Hoffman’s funded this study.

Journal Reference:

  1. Claudia S. Miller, David Kattari, et al. What initiates chemical intolerance? Findings from a large population-based survey of U.S. adults. Environmental Sciences Europe. DOI: 10.1186/s12302-023-00772-x
- Advertisement -

Latest Updates