NIEHS News, October, 2004

[Guest guest]

This is taken from the NIEHS News, October 2004

National Meeting Breaks the Mold

As the 2004 hurricane season nears its end after an unprecedented run of

flooding and other water damage, attention is turning once again to the health

effects of toxic mold infestation. Exposure to mold in residential, public, and

commercial buildings is thought to have caused health problems ranging from

bleeding lungs to hair loss--even to death. But debate continues over many

key questions, such how to best treat exposed individuals. In an effort to push

through questions that still constrain the field, participants at the June

2004 National Meeting on Mold-Related Health Effects: Clinical, Remediation

Worker Protection, and Biomedical Research Issues established a consensus on

mold-related health effects and discussed clinical recommendations and a future

research agenda for the evaluation, diagnosis, treatment, and management of

these health problems. Public health menace. Stachybotrys chartarum

hyphae is just one of many toxic molds whose spores can cause serious adverse

health effects when inhaled.

image credit: Dennis Kunkel Microscopy

The meeting was aimed at an interdisciplinary cross-section of policy makers,

researchers, engineers, advocacy group members, and clinicians. Sponsors

included the NIEHS, the Society for Occupational and Environmental Health, the

Association of Occupational and Environmental Clinics, the s Hopkins

Bloomberg School of Public Health, the Urban Public Health Program of Hunter

College, the University of Medicine and Dentistry of New Jersey School of Public

Health, and the NIH Office of Rare Diseases.

A Gamut of Questions

Outstanding research questions on the health effects of mold exposure run a

broad gamut. Do airborne fungi produce known or unknown compounds that

modulate immunity? Does co-exposure to multiple molds and other allergens

occur, and

how, and with what effect? Does mold exposure produce neurophysiologic and

neurobehavioral abnormalities in children? And how can we best develop

registries to chronicle exposures to mold and fungi?

One leading question is whether exposure to high levels of allergens in

buildings triggers new-onset allergies. Some clinicians at the meeting had

examined individual cases in which mold-contaminated environments appeared to

have

caused new-onset adult asthma, but population-based research is needed to

confirm these findings. Exposure in children seems to cause other respiratory

tract disorders besides allergies. These include rhinosinusitis, cognitive and

developmental effects, psychological effects, and other nonimmunologic health

effects.

To study mold-related health effects, standard assessment tools such as

clinical questionnaires for tracking symptoms and effects are needed, as are

exposure assessment indicators. To date, questionnaires have proven valuable in

assessing population response to abatement. But there are no good, clinically

useful biological markers of exposure for nonallergic health outcomes,

contended Clifford , director of the occupational medicine residency

program

at the Bloomberg School of Public Health. Participants recommended that

diagnostic testing be symptom-based and that exploratory tests for

neurobehavioral, neurologic, immunologic, and allergic effects be developed.

Direct and indirect measures should be further developed and validated, said

J. , an industrial researcher in fungal allergens and toxins at

Carleton University. Markers of early biological effects might be related to

cumulative exposures in moist or contaminated environments. Key questions

presented by Michigan State University food scientist Pestka included

whether toxicokinetics and tissue concentrations in animals correlate with in

vitro effects, and whether airborne exposure data or human tissue levels

correlate with thresholds for immune effects in animals. Participants produced

a

detailed list of research questions, which participants prioritized through a

survey after the meeting. The list will be available in a meeting report due

out this winter.

The Public Health Perspective

Without a consensus on specific aspects of mold-related health effects, the

primary concern from a public health perspective is that affected people need

to be treated and returned to a safe environment. In addition, the mold and

the conditions that led to it need to be corrected.

It is difficult to measure people's exposures to molds, fungi, and their

constituents and metabolic products from different sources. For example, many

molds and fungi produce mycotoxins that further complicate health effects by

acting in a synergistic fashion. Current techniques are limited in their

sensitivity and what they can measure, especially given the wide distribution of

fungi and complex aspects of growth and metabolism. Factoring in cumulative

exposures and all clinically relevant exposures is beyond current capabilities.

In general, large integrated samples are needed for accurate exposure

assessment.

" The bottom line, " explained , " is that indoor exposure [involves] much

more than just fungal material--it's a lot of stuff. " And from a public

health point of view, he said, what's most important is mitigating and treating

the exposure. He acknowledged that the details--for example, knowing the

biologically active agent or the specific spore present--may make a difference

for policy makers, lawyers, and others.

Once a mold problem is identified, exposed individuals should first be

removed from the exposure. Then they should receive treatment depending on

symptoms and diagnosis using the tools of evidence-based medicine. Participants

noted that treatment for cumulative and toxic exposures should be further

researched; doctors do not currently advise prophylactic treatment based on

known

exposure alone, although symptoms, of course, are treated. The effectiveness of

health and remediation interventions also needs probing. It is also

important to clearly communicate with exposed populations after interventions

to let

them know what the exposure means to their health and how to best manage it,

said.

Yet even after abatement, added, some individuals may be

symptomatic. " It's important for everybody to realize there is not a one hundred

percent fix for [mold contamination and exposure], and this is a message that

needs

to go to the clinical world as well as the policy world. "

Cleanup and Prevention

Many issues remain to be resolved around sampling. Generally, participants

agreed that for home abatements, sampling is likely not worth the expense, and

it makes more sense financially to just solve the problem. In large buildings

(particularly office environments), on the other hand, sampling may be

useful to pinpoint the source of exposure, both for legal reasons and for

cleanup

purposes.

But many remain skeptical of sampling's ultimate utility. " Sampling does

little to add to the diagnosis, management, or correction of the problem, " said

Gregg Recer, a research scientist with the New York State Department of

Health. And in practice, determining when a building is safe for individuals

who

experienced mold-related health problems remains a thorny issue. Most experts

agree that visual and olfactory inspection by a competent authority with

appropriate personal protective equipment before and after abatement is the best

strategy.

Work is also needed in developing better guidance for maintenance and

remediation workers. There are no standards or requirements for training, said

Klitzman, an urban public health professor at Hunter College. Some outfits

offer certification, she said, but no hands-on experience--a component that

experts at the conference felt was vital.

For now, there is a general consensus that, at a minimum, workers need some

type of respiratory protection and gloves. " We can come up with general

guidelines, but there's no one-size-fits-all approach, " Klitzman said.

" Professional experience and professional judgment are really paramount here. "

Most of the existing guidance doesn't cover in sufficient detail other

categories of workers who may work in an exposed area on a regular basis, such

as

maintenance workers, construction workers, teachers, and office workers.

Participants will compile new guidance for all groups of workers as a product of

the meeting. As Ted Outwater, a public health educator in the NIEHS Division

of Extramural Research and Training, concluded, " We're into this because we

view workers as our first line of environmental defense. "

As with many environmental threats, preventing exposure is key for mold; in

this case, prevention largely involves correcting moisture problems and

housekeeping deficiencies. Participants agreed that remediation goals should

include addressing underlying moisture problems, removing or cleaning moldy and

damaged materials, protecting workers and occupants, and using containment

procedures appropriate for the conditions. Remediation techniques depend on

moisture source, condition of the structure and furnishings, building materials,

location of mold contamination, presence of additional contaminants, and

effects on operations (for example, whether a business will have to be closed

down

for weeks).

" We have to think very carefully about [performing] outcome studies, " said

. " At this point we certainly know enough that we have to correct the

problem. And figuring out which part of the problem is most important to

correct and what that question means for population health is an important

research question. " At the same time, he said, we need to understand how those

corrective interventions pay off in terms of public health.

Wakefield