The new report issued from the Institute of Medicine of the National Academies states that scientific evidence links mold and other factors related to damp conditions in homes and buildings to asthma symptoms in some people with the chronic disorder, as well as to coughing, wheezing and upper respiratory tract symptoms in otherwise healthy people.

However, the available evidence does not support an association between either indoor dampness or mold and the wide range of other health complaints that have been ascribed to them, the report says. Given the frequent occurrence of moisture problems in buildings and their links to respiratory problems, excessive indoor dampness should be addressed through a broad range of public health initiatives and changes in how buildings are designed, constructed and maintained, said the committee that wrote the report.

"An exhaustive review of the scientific literature made it clear to us that it can be very hard to distinguish the health effects of exposure to mold from all the other factors that may be influencing health in the typical indoor environment," said committee chairwoman Noreen Clark, dean, school of public health, University of Michigan, Ann Arbor. "That said, we were able to find sufficient evidence that certain respiratory problems, including symptoms in asthmatics who are sensitive to mold, are associated with exposure to mold and damp conditions. Even though the available evidence does not link mold or other factors associated with building moisture to all the serious health problems that some attribute to them, excessive indoor dampness is a widespread problem that warrants action at the local, state and national levels."

Excessive dampness influences whether mold as well as bacteria, dust mites and other such agents are present and thrive indoors. Moreover, wetness may cause chemicals and particles to be released from building materials. Many studies of health effects possibly related to indoor dampness do not distinguish the specific health effects of different biological or chemical agents.

Through its careful review of the available scientific studies, the committee found sufficient evidence to conclude that mold and damp conditions are associated with asthma symptoms in asthmatics who are sensitive to mold, and to coughing, wheezing and upper respiratory tract symptoms in otherwise healthy people. However, the evidence did not meet the strict scientific standards needed to establish a clear, causal relationship. An uncommon ailment known as hypersensitivity pneumonitis also is associated with indoor mold exposure in genetically susceptible people. Damp conditions and all they entail may be associated with the onset of asthma, as well as shortness of breath and lower respiratory illness in otherwise healthy children, although the evidence is less certain in these circumstances. Likewise, the presence of visible mold indoors may be linked to lower respiratory tract illness in children, but the evidence is not as strong in this case.

The committee found very few studies that have examined whether mold or other factors associated with indoor dampness are linked to fatigue, neuropsychiatric disorders or other health problems that some people have attributed to fungal infestations of buildings. The little evidence that is available does not support an association, but because of the dearth of well-conducted studies and reliable data, the committee could not rule out the possibility.

The study indicated moisture and mold problems stem from building designs, construction and maintenance practices, and building materials in which wetness lingers. Technical information describing how to control dampness already exists, but architects, engineers, building contractors, facility managers and maintenance staff do not always apply this knowledge, the report says.

Research on various means to prevent or eliminate excessive dampness—including educational initiatives and building renovations or design changes—should be undertaken to find out which are effective. While there is universal agreement that promptly fixing leaks and cleaning up spills or standing water substantially reduces the potential for mold growth, there is little evidence that shows which forms of moisture control or prevention work best at reducing health problems associated with dampness, the report notes.

The committee had insufficient information to recommend either an appropriate level of dampness reduction or a safe level of exposure to organisms and chemicals linked to dampness, but called for studies that compare various ways to limit moisture or eliminate mold and to evaluate whether the interventions improve occupants' health.

The study was sponsored by the Centers for Disease Control and Prevention. The Institute of Medicine is a private, nonprofit institution that provides health policy advice under a congressional charter granted to the National Academy of Sciences.

Some steps homeowners can take to avoid or reduce mold in the home include keeping the humidity level in the house below 40 percent and making sure a home has adequate ventilation and exhaust fans in the kitchen and bathroom. Mold inhibitors can be added to paint, and bathrooms should be cleaned with mold-killing products. It is also recommended that homeowners do not put carpet in bathrooms.

Keeping an eye out for moisture in the home is the first step in mold prevention, and taking care of any mold or moisture problem right away is important to avoid future issues. Realtors are a good source of information and can provide details about mold disclosure as it relates to buying or selling a home.